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Karin Oiwa, Ryuki Tsuji, Rimpei Ueno, Jinyu Li, Linghui Li, Myu Kawase, Keita Nakayama, Natsumi Noguchi, Susmita Roy, Osamu Oki, [Ryotaro Sakakibara](https://orcid.org/0000-0001-7150-2831), [Ken Sakaushi](https://orcid.org/0000-0003-4797-9087), [Masashi Miyakawa](https://orcid.org/0000-0002-0838-8156), [Takashi Taniguchi](https://orcid.org/0000-0002-1467-3105), Takahiro Kondo

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[Hydrophilicity as a Key Factor in Enhancing Oxygen Evolution Reaction on Rhombohedral Boron Monosulfide/Ni-Foam Electrodes with Carbon Material](https://mdr.nims.go.jp/datasets/d71be42d-fdda-4ec5-9b0e-56e6b1e9ee23)

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Hydrophilicity as a Key Factor in Enhancing Oxygen Evolution Reaction on Rhombohedral Boron Monosulfide/Ni-Foam Electrodes with Carbon MaterialHydrophilicity as a Key Factor in Enhancing Oxygen EvolutionReaction on Rhombohedral Boron Monosulfide/Ni-Foam Electrodeswith Carbon MaterialKarin Oiwa,# Ryuki Tsuji,# Rimpei Ueno, Jinyu Li, Linghui Li, Myu Kawase, Keita Nakayama,Natsumi Noguchi, Susmita Roy, Osamu Oki, Ryotaro Sakakibara, Ken Sakaushi, Masashi Miyakawa,Takashi Taniguchi, and Takahiro Kondo*Cite This: ACS Appl. Energy Mater. 2025, 8, 15186−15195 Read OnlineACCESS Metrics & More Article Recommendations *sı Supporting InformationABSTRACT: In this study, we systematically investigated the impact ofcarbon support properties on the oxygen evolution reaction (OER) activity ofrhombohedral boron monosulfide (r-BS), a two-dimensional catalystcomposed solely of main group elements. Specifically, we examined the effectsof crystallinity (crystallite size), defect density (Raman ID/IG ratio), andwettability (water contact angle) for four carbon materials: graphene, graphite,carbon black, and multiwalled carbon nanotube (MWCNT). A large numberof independent r-BS/carbon material/Ni-foam electrodes were fabricated, andthe average current density at 1.8 V vs RHE was evaluated through statisticalanalysis. The OER activity followed the order: graphene ≈ graphite > carbonblack > MWCNT. However, no clear correlation was found with crystallite sizeor ID/IG ratio. In contrast, the contact angle showed a clear inverse relationshipwith OER activity, with measured values of 0, 55, 99, and 113° for graphene,graphite, carbon black, and MWCNT, respectively. The graphene-based composite showed the highest current density, althoughwith large variability. In contrast, the graphite-based composite demonstrated similarly high activity with significantly betterreproducibility. These findings highlight that the hydrophilicity of the carbon support, which governs the detachment of oxygen gasbubbles from the electrode surface, is a dominant factor in high-current-density OER performance. Overall, this study underscoresthe importance of contact angle engineering as a practical design principle for optimizing nonprecious-metal-based catalyst−supportcomposites.KEYWORDS: oxygen evolution reaction, water splitting, water electrolysis, wettability, boron sulfide■ INTRODUCTIONAchieving a sustainable society has brought increasing globalattention to hydrogen as a clean energy carrier.1−3 Amongvarious hydrogen production methods, water electrolysispowered by surplus renewable electricity�such as solar andwind�offers a highly stable and environmentally friendlyapproach.4,5Water electrolysis consists of two half-reactions: thehydrogen evolution reaction (HER) and the oxygen evolutionreaction (OER). While HER proceeds via a two-electrontransfer process, OER involves a more complex four-electronpathway. As a result, OER is kinetically sluggish and typicallybecomes the rate-determining step, limiting the overall energyefficiency of electrolysis.6,7To address this, precious metal-based catalysts such asruthenium oxide (RuOx) and Iridium oxide (IrOx) have beenextensively studied for their excellent OER activity.8−10However, their high cost and scarcity remain significantbarriers to large-scale deployment. Therefore, the developmentof high-performance, nonprecious-metal-based OER electro-catalysts using earth-abundant elements is urgently needed.11,12In recent years, numerous active nonprecious-metal catalystshave been reported.13−16 Our group has focused onrhombohedral boron monosulfide (r-BS), a layered materialcomposed solely of main group elements, as a promising OERcatalyst.17−19 r-BS features a two-dimensional structure formedby a 1:1 atomic ratio of boron and sulfur.20,21 Notably, r-BShas demonstrated enhanced OER performance in alkalinemedia when combined with graphene as a conductivesupport.17,18 This finding highlights the critical influence ofsupport materials on overall catalytic activity and emphasizesReceived: July 8, 2025Revised: October 3, 2025Accepted: October 7, 2025Published: October 13, 2025Articlewww.acsaem.org© 2025 The Authors. Published byAmerican Chemical Society15186https://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−15195This article is licensed under CC-BY-NC-ND 4.0Downloaded via 123.226.1.36 on November 4, 2025 at 06:19:39 (UTC).See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Karin+Oiwa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ryuki+Tsuji"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Rimpei+Ueno"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Jinyu+Li"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Linghui+Li"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Myu+Kawase"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Keita+Nakayama"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Natsumi+Noguchi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Natsumi+Noguchi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Susmita+Roy"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Osamu+Oki"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ryotaro+Sakakibara"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ken+Sakaushi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Masashi+Miyakawa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Takashi+Taniguchi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Takashi+Taniguchi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Takahiro+Kondo"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/showCitFormats?doi=10.1021/acsaem.5c02078&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?goto=articleMetrics&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?goto=recommendations&?ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?goto=supporting-info&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=tgr1&ref=pdfhttps://pubs.acs.org/toc/aaemcq/8/20?ref=pdfhttps://pubs.acs.org/toc/aaemcq/8/20?ref=pdfhttps://pubs.acs.org/toc/aaemcq/8/20?ref=pdfhttps://pubs.acs.org/toc/aaemcq/8/20?ref=pdfwww.acsaem.org?ref=pdfhttps://pubs.acs.org?ref=pdfhttps://pubs.acs.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://www.acsaem.org?ref=pdfhttps://www.acsaem.org?ref=pdfhttps://acsopenscience.org/researchers/open-access/https://creativecommons.org/licenses/by-nc-nd/4.0/https://creativecommons.org/licenses/by-nc-nd/4.0/https://creativecommons.org/licenses/by-nc-nd/4.0/https://creativecommons.org/licenses/by-nc-nd/4.0/https://creativecommons.org/licenses/by-nc-nd/4.0/the importance of rational design in catalyst−supportarchitectures for optimizing OER performance.A carbon support for OER electrocatalysis must meet severalkey requirements: (1) high surface area, (2) high electricalconductivity, and (3) appropriate wettability (hydrophilicity).Each of these factors plays a distinct role in determining theoverall catalytic performance.1) A high surface area is essential to suppress theaggregation of catalyst particles, thereby enhancingtheir dispersion and exposing more active sites.22,23This contributes directly to improving OER activity.2) Electrical conductivity is also critical, especially forsemiconductor catalysts such as r-BS.24 Because thesematerials have limited intrinsic conductivity, a con-ductive carbon support is necessary to ensure efficientcharge transport during electrolysis.25,263) More recently, surface wettability has emerged as acrucial factor. It influences the detachment behavior ofoxygen bubbles formed during OER. Poor wettabilitycan cause gas bubbles to adhere to the electrode surface,blocking active sites and reducing the effective reactionarea.27,28 This leads to increased transport resistance anddeteriorated performance, particularly under highcurrent conditions.Recent studies across various material systems haveunderscored the significance of the balance between hydro-philicity and hydrophobicity.29−36 In particular, the interactionbetween wettability and bubble dynamics is becomingrecognized as a key determinant of OER efficiency.A recent systematic review by Li et al. highlighted thatmicro/nanostructuring of electrode surfaces to achieve super-aerophobicity can break the three-phase contact line. Thisdrastically reduces bubble departure diameters (to ∼ 50 μm),enabling up to a 60% increase in current density andsignificantly lowering overpotential under high-current oper-ation, even with the same catalyst.28Iwata et al. reported that controlling wettability by graduallycoating porous Ni foam with polytetrafluoroethylene (PTFE)changed the oxygen bubble detachment size from 200 μm to4.5 mm. As a result, bubble coverage increased from 0.001 to0.4, and activation overpotential rose from nearly 0 mV to ∼30 mV. These findings provided clear quantitative evidencelinking wettability to transport loss.37In carbon-based systems, Kirti et al. engineered a carbon−polymer composite electrode by tuning surface roughness andbiphasic wettability. They adjusted the contact angle from 48°(hydrophilic) to 92° (hydrophobic), which dramaticallydecreased the Tafel slope from 147 to 47 mV dec−1 andimproved the sustainability of steady-state current throughmore efficient bubble release.38However, the influence of wettability on the OERperformance of catalyst−support composites composed ofcarbon materials and active catalysts has not been systemati-cally explored. In this study, we selected four representativecarbon materials�graphene, graphite, carbon black, andmultiwalled carbon nanotube (MWCNT)�as supports forthe OER catalyst r-BS. Each r-BS−carbon composite wasimmobilized on a Ni-foam substrate, and their electrochemicalperformance was evaluated with careful assessment ofreproducibility.Electrochemical measurements showed that r-BS supportedon graphene and graphite exhibited significantly higher OERactivity, while carbon black and MWCNT-based compositesshowed reduced performance. Importantly, a clear correlationwas observed between OER activity and the wettability of thecarbon support, as quantified by contact angle measurements.These findings indicate that the wettability of the supportsurface plays a critical role in facilitating the detachment ofoxygen gas bubbles during OER, thereby influencing catalyticefficiency. Thus, surface hydrophilicity emerges as a key designparameter in the development of efficient catalyst−supportcomposites for water electrolysis.■ RESULTS AND DISCUSSIONWe first characterized the structural properties of the carbonmaterials used in this study: graphene, graphite, carbon black,and MWCNT. Figure 1 shows the X-ray diffraction (XRD)patterns of these materials.For both graphene and graphite, a sharp diffraction peakcorresponding to the (002) plane was observed around 26°,indicating a well-ordered layered graphitic structure.39,40 Incontrast, carbon black exhibited no distinct diffraction peaks,suggesting an amorphous or highly disordered structure.41 TheXRD pattern of MWCNT also displayed a peak near 26°,corresponding to the (002) plane, as well as a smaller peakattributed to the 100 plane. These features reflect itsmultilayered tubular structure derived from stacked graphenesheets.42Crystallite sizes were estimated from the 002 peak using theScherrer equation.43 The resulting values were 40.7 nm forgraphite, 24.6 nm for graphene, and 4.2 nm for MWCNT. Thelarge crystallite size of graphite, along with its sharp diffractionpeak, indicates a highly ordered layer structure. Grapheneshowed a moderate crystallite size, consistent with its few-layermorphology and expected high dispersibility. MWCNTexhibited the smallest crystallite size, likely due to theirshort-range stacking and structural heterogeneity. For carbonblack, the lack of a well-defined peak prevented estimation ofcrystallite size.Next, the Raman spectra of the carbon materials wereanalyzed, as shown in Figure 2. All samples exhibitedcharacteristic D and G bands in the region of 1300−1600cm−1 (Figure 2a), typical of carbon-based materials. The GFigure 1. XRD patterns of carbon materials.ACS Applied Energy Materials www.acsaem.org Articlehttps://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−1519515187https://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig1&ref=pdfwww.acsaem.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asband (∼1580 cm−1) corresponds to the in-plane vibrationalmode of sp2-bonded carbon atoms, associated with graphiticdomains and used as an indicator of structural order. Incontrast, the D band (∼1350 cm−1) arises from lattice defectsor disorder and reflects the degree of structural imperfectionsin the material.44−47Graphene and graphite displayed sharp and intense G bands,indicative of their high crystallinity and low defect density. Incontrast, carbon black and MWCNT showed D bands ofcomparable or even greater intensity than their G bands,suggesting a higher concentration of defects and greaterstructural disorder. Additionally, MWCNT exhibited a clear2D band near ∼ 2700 cm−1, consistent with the presence ofmultilayer graphene-like structures.47To quantify the degree of disorder, the intensity ratio of theD to G bands (ID/IG) was calculated for each material (Figure2b).48 The results showed a distinct trend: graphene (0.47) <graphite (0.54) < MWCNT (0.99) < carbon black (1.14).These values confirm that graphene and graphite possess well-ordered, low-defect structures, whereas carbon black andMWCNT exhibit higher defect densities. Notably, the high ID/IG ratio of carbon black is consistent with its amorphousnature, as also indicated by the XRD analysis.Taken together, the XRD and Raman spectroscopy resultsreveal clear differences in the structural order and defect levelsamong the four carbon materials. These intrinsic characteristicsare expected to influence interfacial properties with r-BS andpotentially impact the performance of the composite electrodesin OER.Next, composite electrodes were fabricated using r-BSsupported on various carbon materials. The r-BS + carbonmaterial catalyst inks were prepared following a previouslyreported method,17,18 with graphene, graphite, carbon black,and MWCNT used as the respective carbon supports (Scheme1a).To achieve uniform deposition of these inks onto Ni-foamsubstrates, several modified protocols were evaluated based onexisting literature (Figure S2; details provided in theSupporting Information, Experimental Methods). Among thetested methods, the most effective approach involvedsonicating the ink followed by gentle manual shaking (Scheme1b). This method resulted in the most homogeneous andefficient loading of the catalyst onto the Ni-foam surface, asconfirmed by optical imaging (Figure S3 and S4), andexhibited the highest OER activity among the tested protocols(Figure S5).Accordingly, this sonication−shake deposition method wasadopted as the standard procedure for fabricating all catalyst-coated electrodes in this study.Transmission electron microscopy (TEM) was conducted toinvestigate the morphology of r-BS composites prepared withFigure 2. (a) Raman shifts spectra and (b) ID/IG ratio of carbonmaterials.Scheme 1. (a) Schematic Illustration of the Preparation Procedure for r-BS + Carbon Materials in Ethanol with Nafion Binder;(b) Schematic Illustration of r-BS + Carbon Material/Ni-Foam (Connected to a Nickel Wire via Spot Welding)ACS Applied Energy Materials www.acsaem.org Articlehttps://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−1519515188https://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig2&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=sch1&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=sch1&ref=pdfwww.acsaem.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asvarious carbon materials, including graphene, graphite, carbonblack, and MWCNT (Figure 3a). In the TEM images, r-BSappears as darker contrast domains, while the carbon supportstypically appear as lighter or more translucent backgroundstructures. Distinct differences in dispersion behavior wereobserved depending on the type of carbon support. These darkr-BS domains are broadly and relatively uniformly spreadacross the planar carbon sheet structures for graphene andgraphite, indicating good dispersion and close surface contact.In contrast, for carbon black and MWCNT, r-BS domains tendto localize in clusters or adhere along curved or entangledstructures, showing a less uniform spatial distribution andsuggesting a more heterogeneous interfacial interaction. Theseresults indicate that the nature of the carbon supportsignificantly affects the dispersion and interfacial morphologyof the r-BS catalyst. For reference, a RuO2 + graphenecomposite was also examined, and a similar distribution ofRuO2 particles on the graphene surface was confirmed (FigureS6a).In addition, optical microscopy was used to assess themacroscopic surface morphology of the r-BS + carbonmaterial/Ni-foam composite electrodes (Figure 3b). Althoughvariations in visual color tone were observed depending on thecarbon material�potentially indicating differences in apparentloading�the black catalyst inks were generally well distributedacross the Ni-foam substrate. This confirms that uniformcoating was achieved regardless of the carbon type. A similarhomogeneous distribution was also observed for the RuO2 +graphene/Ni-foam electrode (Figure S6b), further supportingthe reproducibility of the coating process.To evaluate the elemental distribution on the surface of thecomposite electrodes, scanning electron microscopy (SEM)combined with energy-dispersive X-ray (EDX) mapping wasperformed (Figure S7). The EDX maps revealed the presenceof C, O, S, and Ni elements across the electrode surface.Notably, the widespread distribution of sulfur confirmed thatthe r-BS component was uniformly deposited over the Ni-foamsubstrate. These results are consistent with the opticalmicroscopy observations and support the conclusion that auniform catalyst coating was successfully achieved for allelectrode samples.Electrochemical measurements were carried out using theprepared r-BS + carbon material/Ni-foam electrodes as theworking electrodes. A standard three-electrode cell config-uration was assembled, as illustrated in Figure S8. Linear sweepvoltammetry (LSV) was conducted to evaluate the OERperformance of each sample. The LSV results for all electrodeconfigurations are shown in Figure S9.To ensure statistical robustness, 27 independent electrodeswere fabricated and measured under each condition. Among allsamples, the pristine Ni-foam exhibited the lowest currentdensity, reflecting its minimal catalytic activity toward OER(Figure S9a). In contrast, the benchmark catalyst, RuO2 +graphene/Ni-foam, displayed an earlier onset of current,indicating its superior intrinsic activity (Figure S9b).For the r-BS-based composite electrodes, the choice ofcarbon support significantly influenced the electrochemicalperformance. In particular, r-BS supported on graphene andgraphite exhibited markedly higher current densities comparedto those supported on carbon black or MWCNT (Figure S9c−f).Figure 4 summarizes the OER performance of r-BS + carbonmaterial/Ni-foam electrodes, based on the LSV data. Figure 4apresents the average LSV curves derived from the multiplemeasurements shown in Figure S9, offering a comparativeoverview of the representative electrochemical behavior foreach electrode.In Figure 4b, the current densities at 1.8 V vs RHE for allindividual samples are displayed as violin plots. Thisvisualization captures not only the mean values but also thedistribution, variability, and reproducibility of the data�making it a central indicator for evaluating OER performancein this study.Figure 3. (a) TEM images of r-BS + carbon materials (graphene,graphite, carbon black, and MWCNT). (b) Optical microscopeimages of r-BS + carbon material/Ni-foam.Figure 4. Comparison of the (a) average LSV curves and (b) current density at 1.8 V vs RHE for r-BS + carbon material/Ni-foam.ACS Applied Energy Materials www.acsaem.org Articlehttps://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−1519515189https://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig3&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig4&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig4&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig4&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig4&ref=pdfwww.acsaem.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asThe violin plots reveal that the r-BS composites supportedon graphene and graphite delivered the highest currentdensities. Notably, the graphite-supported electrode showeda narrower distribution, reflecting superior reproducibility andstability. In contrast, the graphene-supported electrodeachieved the highest peak performance but exhibited greatervariability among samples. The carbon black-supportedelectrode showed moderate activity, while the MWCNT-based composite displayed the lowest current density amongthe tested materials.These results clearly indicate that the choice of carbonsupport significantly affects not only the absolute OERperformance, but also its reproducibility.The RuO2 + graphene/Ni-foam electrode exhibited an earlyonset of current, indicating efficient OER initiation at lowerpotentials (Figure 4a). However, its final current density at 1.8V vs RHE was lower than that of the r-BS-based composites(Figure 4b), suggesting limited performance in the high-potential region. This trend is consistent with our previousreports, where r-BS-based electrodes outperformed RuO2-based systems.17,18To provide a clear comparison, the key electrochemicalparameters of all tested electrodes, including overpotential at10 mA cm−2, current density at 1.8 V vs RHE, and Tafel slope,are summarized in Table S1. This table highlights the distinctdifferences among the carbon-supported r-BS composites andreference electrodes.In addition, to benchmark the performance of r-BS +carbon/Ni-foam electrodes against previously reported sulfide-based OER catalysts, we compiled the overpotential and Tafelslope values from the literature together with our results(Table S2). This comparison confirms that the r-BS-basedcomposites investigated here exhibit competitive activityrelative to other representative metal sulfide systems.It should be noted that the overall OER activities observedin this study are lower than those reported previously.17,18 Thisdiscrepancy is likely attributed to suboptimal electrodepreparation, particularly the lack of optimization in surfacewettability (as discussed later) and drying conditions, whichmay have limited the intrinsic performance of electrocatalysts.For a more comprehensive evaluation of the catalyticperformance, we performed electrochemical impedance spec-troscopy (EIS), double-layer capacitance (Cdl), and electro-chemically active surface area (ECSA) measurements. TheNyquist plots (Figure S13) reveal differences in charge-transferresistance among the composites. In particular, the r-BS +graphene/Ni-foam electrode exhibited the smallest onset andsemicircle diameter, corresponding to the lowest solutionseries resistance and charge-transfer resistance, respectively,while the r-BS + MWCNT/Ni-foam electrode showed thelargest onset and semicircle, indicating sluggish interfacialkinetics.Cyclic voltammetry in the non-Faradaic region (Figure S14)was used to estimate Cdl, and the resulting ECSA values wereobtained from the slope of ΔJ versus scan rate (Figure S15). Asshown in Figure S15, the carbon black-based electrodedisplayed the largest ΔJ and consequently the highest apparentECSA, while graphene- and graphite-supported electrodesexhibited much smaller values. This result clearly indicates thatelectrochemically accessible surface area alone cannot explainthe observed differences in OER activity. Therefore, weconsidered that other surface-related properties must beinvolved, and turned our attention to wettability as a possibledecisive factor.In addition to these activity-related factors, we alsoexamined the durability of the r-BS + carbon/Ni-foamelectrodes (Figure S16). Although all samples retained activityover 8000 s, the CP curves revealed that the r-BS compositesoperated at lower potentials than the RuO2 electrode,indicating that their catalytic activity was sufficientlymaintained. The CA profiles showed gradual current variationsover time, but overall the r-BS-based electrodes preservedstable operation throughout the test period.Next, we investigated the wettability of the electrodesurfaces, as it is considered one of the key factors influencingthe performance differences among the carbon supports.Figure 5a shows the contact angles measured at 0.1 s afterthe deposition of a water droplet on the surface of each r-BS +carbon material/Ni-foam electrode. The pristine Ni-foam andthe r-BS + MWCNT/Ni-foam electrode exhibited significanthydrophobicity, with contact angles of 118.4° and 112.6°,respectively. In contrast, the electrodes with graphite, carbonblack, and MWCNT supports showed contact angles of 55.4°,98.6°, and 112.6°, respectively, indicating that wettability variesconsiderably depending on the type of carbon support.Figure 5. (a) Contact angle images captured at 0.1 s after water droplet deposition onto r-BS + carbon material/Ni-foam during wettability tests.(b) Contact angle variation over time.ACS Applied Energy Materials www.acsaem.org Articlehttps://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−1519515190https://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig5&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig5&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig5&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig5&ref=pdfwww.acsaem.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asNotably, the r-BS + graphene/Ni-foam electrode demon-strated a contact angle of 0°, indicating complete hydro-philicity, with the water droplet spreading immediately acrossthe surface. The RuO2 + graphene/Ni-foam electrode alsoexhibited moderate wettability, with a contact angle of 83.4°.Figure 5b presents the time-dependent variation in contactangle over 20 s after droplet deposition. For all electrodesexcept the graphene-based one, a slight decrease in contactangle was observed over time. However, the relative order ofwettability remained largely unchanged throughout themeasurement period. These results confirm that the initialcontact angle serves as a reliable indicator of overall surfacewettability.Figure 6 illustrates the relationship between the contactangle and the average current density at 1.8 V vs RHE for eachr-BS + carbon material/Ni-foam electrode. The dashed line inthe plot represents the fitted trend based on the measured datafor r-BS-based electrodes, excluding the RuO2 + graphene/Ni-foam benchmark.Overall, a clear inverse correlation was observed: electrodeswith smaller contact angles (i.e., more hydrophilic surfaces)exhibited higher OER current densities. This trend stronglysuggests a direct influence of surface wettability on electro-catalytic performance.In particular, the graphene-supported electrode demonstra-ted complete hydrophilicity with a contact angle of 0° andsimultaneously achieved the highest current density. Incontrast, the Ni-foam and MWCNT-based electrodes showedlarge contact angles exceeding 110°, along with significantlylower current densities. Graphite and carbon black electrodesexhibited intermediate wettability and performance, indicatinga continuous dependence of OER activity on surfacehydrophilicity.These findings clearly confirm that the “additional factors”suggested by the ECSA analysis are directly related to surfacewettability. These results demonstrate that wettability is notmerely a surface property but plays a direct role in determiningOER activity. It likely affects both the detachment efficiency ofevolved oxygen gas bubbles and the accessibility of hydroxideions to the catalyst surface. In particular, highly hydrophilicsurfaces facilitate rapid O2 bubble release, thereby maintainingactive catalytic sites and enabling sustained, efficient oxygenevolution.Figure 7a and 7b show the electrode surfaces after waterelectrolysis. Figure 7a presents the pristine Ni-foam electrode,while Figure 7b displays the r-BS + MWCNT/Ni-foamelectrode following electrolysis in water. In the case of Ni-foam, oxygen bubbles generated during electrolysis detachedrelatively quickly, and no significant bubble accumulation wasobserved on the surface. By contrast, the MWCNT-supportedelectrode exhibited a large number of residual oxygen bubblesthat remained adhered to the electrode surface.Figure 7c provides a schematic illustration of the r-BS +MWCNT/Ni-foam electrode structure and bubble behavior.The MWCNT layer forms a microscopically rough surface onthe Ni-foam, imparting a water-repellent nature due to the so-called “lotus effect.”49−52 This micro texture leads to a highdegree of surface hydrophobicity.As a result of this strong hydrophobicity, oxygen bubblesgenerated during the OER tend to adhere tightly to theelectrode surface rather than detaching efficiently. This bubbleaccumulation can temporarily block active sites on the catalystsurface and hinder the supply of hydroxide ions, both of whichcontribute to a decline in OER performance.These findings suggest that surface wettability significantlyinfluences bubble detachment behavior during OER. Con-sequently, controlling the wettability of electrode surfaces is animportant strategy for optimizing catalytic performance inelectrochemical systems.Finally, the representative physicochemical properties of thecarbon materials used in this study are discussed in terms ofthe relationship with their OER performance. As summarizedin Table 1, electrical conductivity, specific surface area, andedge density have traditionally been employed as keyindicators for evaluating the effectiveness of catalyst supportsin literature.53−56 In this work, we extended this analysis byexperimentally determining the crystallite size (via XRD), theID/IG ratio (via Raman spectroscopy, as an inverse indicator ofcrystallinity), and the water contact angle (at 0.1 s) tosystematically evaluate their relationship with OER perform-ance.In addition, we attempted to obtain the BET surface area ofthe r-BS + carbon composites. However, as a representativecase, the BET analysis of the r-BS + graphene/Ni-foamelectrode yielded a negative specific surface area value,indicating that the nitrogen adsorption was too low for reliabledetermination (Figure S17). This outcome is likely because thecatalyst was deposited only on the outer surface of the Ni-foamwithout forming a sufficiently porous structure. Nevertheless,since electrochemical reactions predominantly occur at theFigure 6. Plot of the relationship between contact angle and averagecurrent density at 1.8 V vs RHE for r-BS + carbon material/Ni-foamelectrodes. The dashed line represents the fit result. Error bars for thecurrent density indicate the standard deviation derived from the dataplotted in Figure 4b.Figure 7. Photographs of sample surfaces after water electrolysis. (a)Ni-foam and (b) r-BS + MWCNT/Ni-foam. Schematic image of O2bubbles that do not detach due to the hydrophobicity of the samplesurface. (c) Schematic illustration of O2 bubbles that do not detachdue to the hydrophobicity of the sample surface.ACS Applied Energy Materials www.acsaem.org Articlehttps://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−1519515191https://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig6&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig6&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig6&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig6&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig7&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig7&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig7&ref=pdfhttps://pubs.acs.org/doi/10.1021/acsaem.5c02078?fig=fig7&ref=pdfwww.acsaem.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-aselectrode surface, the absence of bulk porosity is not expectedto hinder OER activity. For reference, literature values of thespecific surface area for each carbon material are summarizedin Table 1.Graphene exhibited moderate crystallinity (24.6 nm), a lowdefect density (ID/IG = 0.47), and complete hydrophilicity(contact angle = 0°), resulting in the highest OER currentdensity among all materials tested. Graphite also demonstratedhigh crystallinity (40.7 nm), a relatively low defect density(0.54), and moderate wettability (55.4°), achieving thesecond-highest OER activity. However, graphite showed betterreproducibility in OER performance compared to graphene.Carbon black, despite its high surface area and edge density,showed low crystallinity (ID/IG = 1.14) and poor wettability(contact angle = 98.6°). Consequently, it exhibited onlymoderate OER performance, likely limited by its hydrophobicnature.MWCNTs had the smallest crystallite size (4.2 nm),relatively high defect density (ID/IG = 0.99), and are knownfor their high electrical conductivity. However, they displayedthe highest contact angle (112.6°), indicating strong hydro-phobicity, and recorded the lowest OER activity.These results suggest that while electronic and structuralproperties of the carbon materials do influence OERperformance to some extent, wettability�particularly underhigh-current-density conditions�plays a dominant role bycontrolling oxygen bubble detachment behavior and maintain-ing reaction continuity.This insight highlights the critical importance of surfacewettability control as a new and effective design parameter foroptimizing catalyst−support composites, beyond conventionalmaterial property comparisons. For instance, introducinghydrophilic modifiers to defect-free yet hydrophobic materialssuch as MWCNTs could offer a promising strategy�leveraging their inherent electrical conductivity and corrosionresistance while simultaneously improving oxygen bubblerelease through enhanced surface wettability. This compositeapproach may enable the design of advanced catalyst systemsthat synergistically integrate structural stability with improvedgas transport dynamics.■ CONCLUSIONSIn this study, we selected rhombohedral boron monosulfide (r-BS), a two-dimensional catalyst composed solely of main-group elements, as a model system. We fabricated a largenumber of composite electrodes by integrating r-BS with fourcarbon supports�graphene, graphite, carbon black, andmultiwalled carbon nanotube (MWCNT)�that differ insurface wettability. Structural analysis, conductivity measure-ments, and water contact angle evaluations were conducted tosystematically examine the correlation between these materialproperties and oxygen evolution reaction (OER) performance.When evaluated at 1.8 V vs RHE, r-BS compositessupported on graphene and graphite exhibited the highestaverage current densities, followed by carbon black andMWCNT. The contact angles measured at 0.1 s were 0° forgraphene, 55° for graphite, 99° for carbon black, and 113° forMWCNT. A clear correlation was observed between thecontact angle and the OER current density.This behavior, which cannot be explained solely bydifferences in surface area or electrical conductivity, clearlydemonstrates that the hydrophilicity of the support�governing the detachment of oxygen gas bubbles�is thedominant factor in high-current-density OER performance.Therefore, surface modification and support selection basedon contact angle should be regarded as a top-priority strategyfor the rational design and optimization of nonprecious-metal-based catalyst−support composites.■ ASSOCIATED CONTENT*sı Supporting InformationThe Supporting Information is available free of charge athttps://pubs.acs.org/doi/10.1021/acsaem.5c02078.Experimental methods, supplementary text, Figures S1−S17, and Tables S1 and S2 (PDF)■ AUTHOR INFORMATIONCorresponding AuthorTakahiro Kondo − Department of Materials Science, Instituteof Pure and Applied Sciences, University of Tsukuba,Tsukuba, Ibaraki 305-8573, Japan; Hydrogen BorideResearch Center, Tsukuba Institute of Advanced Research,University of Tsukuba, Tsukuba, Ibaraki 305-8577, Japan;Research Center for Energy and Environmental Materials,National Institute for Materials Science, Tsukuba, Ibaraki305-0044, Japan; The Advanced Institute for MaterialsResearch, Tohoku University, Sendai, Miyagi 980-8577,Japan; orcid.org/0000-0001-8457-9387;Email: takahiro@ims.tsukuba.ac.jpAuthorsKarin Oiwa − Graduate School of Science and Technology,University of Tsukuba, Tsukuba, Ibaraki 305-8574, JapanRyuki Tsuji − Department of Materials Science, Institute ofPure and Applied Sciences, University of Tsukuba, Tsukuba,Ibaraki 305-8573, Japan; Hydrogen Boride Research Center,Tsukuba Institute of Advanced Research, University ofTsukuba, Tsukuba, Ibaraki 305-8577, JapanRimpei Ueno − Hydrogen Boride Research Center, TsukubaInstitute of Advanced Research, University of Tsukuba,Tsukuba, Ibaraki 305-8577, JapanTable 1. Summary of Physicochemical Properties of Carbon Materials Used in This Studyaliterature values experimental valuescarbon materials electrical conductivity (S/cm) surface area (m2/g) qualitative edge density crystallite size (nm) ID/IG ratio contact angle at 0.1 s (°)graphene 103−107 1000−3000 moderate 24.6 0.47 0°graphite 101−102 1−10 moderate 40.7 0.54 55.4°carbon black 102−103 10−1000 high n.d. 1.14 98.6°MWCNT 104−105 100−500 low 4.2 0.99 112.6°aLiterature values include electrical conductivity, surface area, and qualitative edge density.53−56 Experimental values include crystallite size (fromXRD), ID/IG ratio (from Raman spectroscopy), and water contact angle at 0.1 s.ACS Applied Energy Materials www.acsaem.org Articlehttps://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−1519515192https://pubs.acs.org/doi/10.1021/acsaem.5c02078?goto=supporting-infohttps://pubs.acs.org/doi/suppl/10.1021/acsaem.5c02078/suppl_file/ae5c02078_si_001.pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Takahiro+Kondo"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0001-8457-9387mailto:takahiro@ims.tsukuba.ac.jphttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Karin+Oiwa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ryuki+Tsuji"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Rimpei+Ueno"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Jinyu+Li"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfwww.acsaem.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-asJinyu Li − Hydrogen Boride Research Center, TsukubaInstitute of Advanced Research, University of Tsukuba,Tsukuba, Ibaraki 305-8577, JapanLinghui Li − Hydrogen Boride Research Center, TsukubaInstitute of Advanced Research, University of Tsukuba,Tsukuba, Ibaraki 305-8577, JapanMyu Kawase − Hydrogen Boride Research Center, TsukubaInstitute of Advanced Research, University of Tsukuba,Tsukuba, Ibaraki 305-8577, JapanKeita Nakayama − Hydrogen Boride Research Center,Tsukuba Institute of Advanced Research, University ofTsukuba, Tsukuba, Ibaraki 305-8577, JapanNatsumi Noguchi − Hydrogen Boride Research Center,Tsukuba Institute of Advanced Research, University ofTsukuba, Tsukuba, Ibaraki 305-8577, JapanSusmita Roy − Department of Materials Science, Institute ofPure and Applied Sciences, University of Tsukuba, Tsukuba,Ibaraki 305-8573, JapanOsamu Oki − Department of Materials Science, Institute ofPure and Applied Sciences, University of Tsukuba, Tsukuba,Ibaraki 305-8573, Japan; Hydrogen Boride Research Center,Tsukuba Institute of Advanced Research, University ofTsukuba, Tsukuba, Ibaraki 305-8577, JapanRyotaro Sakakibara − Research Center for MaterialsNanoarchitectonics, National Institute for Materials Science,Tsukuba, Ibaraki 305-0044, Japan; orcid.org/0000-0001-7150-2831Ken Sakaushi − Department of Materials Science, Institute ofPure and Applied Sciences, University of Tsukuba, Tsukuba,Ibaraki 305-8573, Japan; Research Center for Energy andEnvironmental Materials, National Institute for MaterialsScience, Tsukuba, Ibaraki 305-0044, Japan; orcid.org/0000-0003-4797-9087Masashi Miyakawa − Research Center for MaterialsNanoarchitectonics, National Institute for Materials Science,Tsukuba, Ibaraki 305-0044, Japan; orcid.org/0000-0002-0838-8156Takashi Taniguchi − Research Center for MaterialsNanoarchitectonics, National Institute for Materials Science,Tsukuba, Ibaraki 305-0044, Japan; orcid.org/0000-0002-1467-3105Complete contact information is available at:https://pubs.acs.org/10.1021/acsaem.5c02078Author Contributions#K.O. and R.T. contributed equally to this work.NotesThe authors declare no competing financial interest.■ ACKNOWLEDGMENTSThis work was supported by JST A-step Program Japan (grantno. JPMJTR22T4), JSPS KAKENHI (grant nos.JP21H00015:B01, JP21H05012, JP22K18964, JP23H01843,JP23K26536, JP24H02204, and JP25K22213), GteX ProgramJapan (grant nos. JPMJGX23H2 and JPMJGX23H1), andSumitomo Electric Industries, Ltd. The authors gratefullyacknowledge Keisuke Shinoda (NIMS) for his support withthe TEM observations.■ REFERENCES(1) Staffell, I.; Scamman, D.; Velazquez Abad, A.; Balcombe, P.;Dodds, P. E.; Ekins, P.; Shah, N.; Ward, K. R. The Role of Hydrogenand Fuel Cells in the Global Energy System. Energy Environ. Sci. 2019,12, 463−491.(2) Kovac,̌ A.; Paranos, M.; Marcius,̌ D. Hydrogen in EnergyTransition: A Review. Int. J. Hydrogen Energy 2021, 46 (16), 10016−10035.(3) Dincer, I. Hydrogen 1.0: A New Age. Int. J. Hydrogen Energy2023, 48 (43), 16143−16147.(4) Oliveira, A. M.; Beswick, R. R.; Yan, Y. A Green HydrogenEconomy for a Renewable Energy Society. Curr. Opin. Chem. Eng.2021, 33, No. 100701.(5) Amin, M.; Shah, H. H.; Fareed, A. G.; Khan, W. U.; Chung, E.;Zia, A.; Rahman Farooqi, Z. U.; Lee, C. Hydrogen Productionthrough Renewable and Non-Renewable Energy Processes and TheirImpact on Climate Change. Int. J. Hydrogen Energy 2022, 47 (77),33112−33134.(6) Wang, X.; Zhong, H.; Xi, S.; Lee, W. S. V.; Xue, J. Understandingof Oxygen Redox in the Oxygen Evolution Reaction. Adv. Mater.2022, 34 (50), No. 2107956.(7) Xie, X.; Du, L.; Yan, L.; Park, S.; Qiu, Y.; Sokolowski, J.; Wang,W.; Shao, Y. Oxygen Evolution Reaction in Alkaline Environment:Material Challenges and Solutions. Adv. Funct. Mater. 2022, 32 (21),No. 2110036.(8) Qin, R.; Chen, G.; Feng, X.; Weng, J.; Han, Y. Ru/Ir-BasedElectrocatalysts for Oxygen Evolution Reaction in Acidic Conditions:From Mechanisms, Optimizations to Challenges. Adv. Sci. 2024, 11(21), No. 2309364.(9) Spöri, C.; Briois, P.; Nong, H. N.; Reier, T.; Billard, A.; Kühl, S.;Teschner, D.; Strasser, P. Experimental Activity Descriptors forIridium-Based Catalysts for the Electrochemical Oxygen EvolutionReaction (OER). ACS Catal. 2019, 9 (8), 6653−6663.(10) Tsuji, R.; Koshino, Y.; Masutani, H.; Haruyama, Y.; Niibe, M.;Suzuki, S.; Nakashima, S.; Fujisawa, H.; Ito, S. Water ElectrolysisUsing Thin Pt and RuOx Catalysts Deposited by a Flame-AnnealingMethod on Pencil-Lead Graphite-Rod Electrodes. ACS Omega 2020,5 (11), 6090−6099.(11) Shi, Q.; Zhu, C.; Du, D.; Lin, Y. Robust Noble Metal-BasedElectrocatalysts for Oxygen Evolution Reaction. Chem. Soc. Rev. 2019,48, 3181−3192.(12) Wu, Z. P.; Lu, X. F.; Zang, S. Q.; Lou, X. W. Non-Noble-Metal-Based Electrocatalysts toward the Oxygen Evolution Reaction. Adv.Funct. Mater. 2020, 30 (15), No. 1910274.(13) Chen, Y.; Li, Q.; Lin, Y.; Liu, J.; Pan, J.; Hu, J.; Xu, X. BoostingOxygen Evolution Reaction by FeNi Hydroxide-Organic FrameworkElectrocatalyst toward Alkaline Water Electrolyzer. Nat. Commun.2024, 15 (1), 7278.(14) Rafiq, M.; Harrath, K.; Feng, M.; Li, R.; Woldu, A. R.; Chu, P.K.; Hu, L.; Lu, F.; Yao, X. NixB/Mo0.8B3 Nanorods Encapsulated by aBoron-Rich Amorphous Layer for Universal PH Water Splitting at theAmpere Level. Adv. Energy. Mater. 2024, 14 (45), No. 2402866.(15) Zahran, Z. N.; Mohamed, E. A.; Tsubonouchi, Y.; Ishizaki, M.;Togashi, T.; Kurihara, M.; Saito, K.; Yui, T.; Yagi, M. ElectrocatalyticWater Splitting with Unprecedentedly Low Overpotentials by NickelSulfide Nanowires Stuffed into Carbon Nitride Scabbards. EnergyEnviron. Sci. 2021, 14 (10), 5358−5365.(16) Arcas, R.; Koshino, Y.; Mas-Marzá, E.; Tsuji, R.; Masutani, H.;Miura-Fujiwara, E.; Haruyama, Y.; Nakashima, S.; Ito, S.; Fabregat-Santiago, F. Pencil Graphite Rods Decorated with Nickel and Nickel-Iron as Low-Cost Oxygen Evolution Reaction Electrodes. Sustain.Energy Fuels 2021, 5 (15), 3929−3938.(17) Li, L.; Hagiwara, S.; Jiang, C.; Kusaka, H.; Watanabe, N.; Fujita,T.; Kuroda, F.; Yamamoto, A.; Miyakawa, M.; Taniguchi, T.; Hosono,H.; Otani, M.; Kondo, T. Boron Monosulfide as an Electrocatalyst forthe Oxygen Evolution Reaction. Chem. Eng. J. 2023, 471, No. 144489.(18) Li, L.; Watanabe, N.; Jiang, C.; Yamamoto, A.; Fujita, T.;Miyakawa, M.; Taniguchi, T.; Hosono, H.; Kondo, T. Developmentof a Highly Stable Nickel-Foam-Based Boron Monosulfide−GrapheneElectrocatalyst with a High Current Density for the Oxygen EvolutionReaction. Sci. Technol. Adv. Mater. 2023, 24 (1), No. 2277681.ACS Applied Energy Materials www.acsaem.org Articlehttps://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−1519515193https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Linghui+Li"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Myu+Kawase"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Keita+Nakayama"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Natsumi+Noguchi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Susmita+Roy"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Osamu+Oki"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ryotaro+Sakakibara"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0001-7150-2831https://orcid.org/0000-0001-7150-2831https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Ken+Sakaushi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0003-4797-9087https://orcid.org/0000-0003-4797-9087https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Masashi+Miyakawa"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0002-0838-8156https://orcid.org/0000-0002-0838-8156https://pubs.acs.org/action/doSearch?field1=Contrib&text1="Takashi+Taniguchi"&field2=AllField&text2=&publication=&accessType=allContent&Earliest=&ref=pdfhttps://orcid.org/0000-0002-1467-3105https://orcid.org/0000-0002-1467-3105https://pubs.acs.org/doi/10.1021/acsaem.5c02078?ref=pdfhttps://doi.org/10.1039/C8EE01157Ehttps://doi.org/10.1039/C8EE01157Ehttps://doi.org/10.1016/j.ijhydene.2020.11.256https://doi.org/10.1016/j.ijhydene.2020.11.256https://doi.org/10.1016/j.ijhydene.2023.01.124https://doi.org/10.1016/j.coche.2021.100701https://doi.org/10.1016/j.coche.2021.100701https://doi.org/10.1016/j.ijhydene.2022.07.172https://doi.org/10.1016/j.ijhydene.2022.07.172https://doi.org/10.1016/j.ijhydene.2022.07.172https://doi.org/10.1002/adma.202107956https://doi.org/10.1002/adma.202107956https://doi.org/10.1002/adfm.202110036https://doi.org/10.1002/adfm.202110036https://doi.org/10.1002/advs.202309364https://doi.org/10.1002/advs.202309364https://doi.org/10.1002/advs.202309364https://doi.org/10.1021/acscatal.9b00648?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acscatal.9b00648?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acscatal.9b00648?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsomega.0c00074?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsomega.0c00074?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsomega.0c00074?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1039/C8CS00671Ghttps://doi.org/10.1039/C8CS00671Ghttps://doi.org/10.1002/adfm.201910274https://doi.org/10.1002/adfm.201910274https://doi.org/10.1038/s41467-024-51521-4https://doi.org/10.1038/s41467-024-51521-4https://doi.org/10.1038/s41467-024-51521-4https://doi.org/10.1002/aenm.202402866https://doi.org/10.1002/aenm.202402866https://doi.org/10.1002/aenm.202402866https://doi.org/10.1039/D1EE00509Jhttps://doi.org/10.1039/D1EE00509Jhttps://doi.org/10.1039/D1EE00509Jhttps://doi.org/10.1039/D1SE00351Hhttps://doi.org/10.1039/D1SE00351Hhttps://doi.org/10.1016/j.cej.2023.144489https://doi.org/10.1016/j.cej.2023.144489https://doi.org/10.1080/14686996.2023.2277681https://doi.org/10.1080/14686996.2023.2277681https://doi.org/10.1080/14686996.2023.2277681https://doi.org/10.1080/14686996.2023.2277681www.acsaem.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as(19) Hagiwara, S.; Kuroda, F.; Kondo, T.; Otani, M. ElectrocatalyticMechanisms for an Oxygen Evolution Reaction at a RhombohedralBoron Monosulfide Electrode/Alkaline Medium Interface. ACS Appl.Mater. Interfaces 2023, 15 (43), 50174−50184.(20) Sasaki, T.; Takizawa, H.; Uheda, K.; Endo, T. High PressureSynthesis of Binary B-S Compounds. Phys. Status Solidi B 2001, 223(1), 29−33.(21) Kusaka, H.; Ishibiki, R.; Toyoda, M.; Fujita, T.; Tokunaga, T.;Yamamoto, A.; Miyakawa, M.; Matsushita, K.; Miyazaki, K.; Li, L.;Shinde, S. L.; Lima, M. S. L.; Sakurai, T.; Nishibori, E.; Masuda, T.;Horiba, K.; Watanabe, K.; Saito, S.; Miyauchi, M.; Taniguchi, T.;Hosono, H.; Kondo, T. Crystalline Boron Monosulfide Nanosheetswith Tunable Bandgaps. J. Mater. Chem. A 2021, 9 (43), 24631−24640.(22) Sun, S.; Li, H.; Xu, Z. J. Impact of Surface Area in Evaluation ofCatalyst Activity. Joule 2018, 2 (6), 1024−1027.(23) Wu, T.; Han, M. Y.; Xu, Z. J. Size Effects of Electrocatalysts:More Than a Variation of Surface Area. ACS Nano 2022, 16 (6),8531−8539.(24) Watanabe, N.; Miyazaki, K.; Toyoda, M.; Takeyasu, K.; Tsujii,N.; Kusaka, H.; Yamamoto, A.; Saito, S.; Miyakawa, M.; Taniguchi,T.; Aizawa, T.; Mori, T.; Miyauchi, M.; Kondo, T. RhombohedralBoron Monosulfide as a P-Type Semiconductor. Molecules 2023, 28(4), 1896.(25) Zou, S.; Burke, M. S.; Kast, M. G.; Fan, J.; Danilovic, N.;Boettcher, S. W. Fe (Oxy)Hydroxide Oxygen Evolution ReactionElectrocatalysis: Intrinsic Activity and the Roles of ElectricalConductivity, Substrate, and Dissolution. Chem. Mater. 2015, 27(23), 8011−8020.(26) Zhao, X.; Zhang, H.; Yan, Y.; Cao, J.; Li, X.; Zhou, S.; Peng, Z.;Zeng, J. Engineering the Electrical Conductivity of Lamellar Silver-Doped Cobalt(II) Selenide Nanobelts for Enhanced OxygenEvolution. Angew. Chem., Int. Ed. 2017, 56 (1), 328−332.(27) Dastafkan, K.; Li, Y.; Zeng, Y.; Han, L.; Zhao, C. EnhancedSurface Wettability and Innate Activity of an Iron Borate Catalyst forEfficient Oxygen Evolution and Gas Bubble Detachment. J. Mater.Chem. A 2019, 7 (25), 15252−15261.(28) Li, M.; Xie, P.; Yu, L.; Luo, L.; Sun, X. Bubble Engineering onMicro-/Nanostructured Electrodes for Water Splitting. ACS Nano2023, 17 (23), 23299−23316.(29) Li, Y.; Zhao, C. Enhancing Water Oxidation Catalysis on aSynergistic Phosphorylated NiFe Hydroxide by Adjusting CatalystWettability. ACS Catal. 2017, 7 (4), 2535−2541.(30) Wang, R.; Jiang, W.; Xia, D.; Liu, T.; Gan, L. Improving theWettability of Thin-Film Rotating Disk Electrodes for ReliableActivity Evaluation of Oxygen Electrocatalysts by Triggering OxygenReduction at the Catalyst-Electrolyte-Bubble Triple Phase Bounda-ries. J. Electrochem. Soc. 2018, 165 (7), F436−F440.(31) Liu, G.; Wu, Y.; Wang, M.; Yao, R.; Li, N.; Zhao, Y.; Zhao, F.;Li, J. Phosphate Ions-Functionalized and Wettability-Tuned NickelFerrite for Boosted Oxygen Evolution Performance. Int. J. HydrogenEnergy 2019, 44 (49), 26992−27000.(32) Fujimura, T.; Hikima, W.; Fukunaka, Y.; Homma, T. Analysisof the Effect of Surface Wettability on Hydrogen Evolution Reactionin Water Electrolysis Using Micro-Patterned Electrodes. Electrochem.commun. 2019, 101, 43−46.(33) Kim, J.; Jung, S. M.; Lee, N.; Kim, K. S.; Kim, Y. T.; Kim, J. K.Efficient Alkaline Hydrogen Evolution Reaction Using Super-aerophobic Ni Nanoarrays with Accelerated H2 Bubble Release.Adv. Mater. 2023, 35 (52), No. 2305844.(34) Jiang, W.; Huang, X.; Ke, W.; Sheng, L.; Li, J. J.; Zhu, F.;Cheng, W.; Zhang, Z.; Lao, Y.; Chen, Y. Tuning Wettability of Nickel-Based Electrode by Micro-Nano Surface Structure to Boost OERCatalysis. J. Alloys Compd. 2023, 965, No. 171367.(35) Shao, X.; Li, D.; Zhou, A.; Zhu, L.; Du, Y.; Li, B.; Zhang, Y.;Cao, L.; Yang, J. Superhydrophilic CoMoO4 with High OxygenVacancy for Outstanding Alkaline OER. Int. J. Hydrogen Energy 2024,58, 1284−1294.(36) Zhu, F.; Wen, X.; Li, X.; Wang, Y.; Shao, K.; Shen, S.; Zhao, X.Tuning the Wettability of Binary Alloy Electrodes to Promote OERCatalysis in Alkaline Media by Group Distribution Ratio. ACS Appl.Energy Mater. 2025, 8 (2), 1210−1219.(37) Iwata, R.; Zhang, L.; Wilke, K. L.; Gong, S.; He, M.; Gallant, B.M.; Wang, E. N. Bubble Growth and Departure Modes on Wettable/Non-Wettable Porous Foams in Alkaline Water Splitting. Joule 2021,5 (4), 887−900.(38) Kirti; Nandha, N.; Singh, P. S.; Srivastava, D. N. ImprovedOER Performance on the Carbon Composite Electrode throughTailored Wettability. ACS Appl. Energy Mater. 2021, 4 (9), 9618−9626.(39) Li, Z. Q.; Lu, C. J.; Xia, Z. P.; Zhou, Y.; Luo, Z. X-RayDiffraction Patterns of Graphite and Turbostratic Carbon. Carbon2007, 45 (8), 1686−1695.(40) Bogachuk, D.; Tsuji, R.; Martineau, D.; Narbey, S.; Herterich, J.P.; Wagner, L.; Suginuma, K.; Ito, S.; Hinsch, A. Comparison ofHighly Conductive Natural and Synthetic Graphites for Electrodes inPerovskite Solar Cells. Carbon 2021, 178, 10−18.(41) Pawlyta, M.; Rouzaud, J. N.; Duber, S. Raman Micro-spectroscopy Characterization of Carbon Blacks: Spectral Analysisand Structural Information. Carbon 2015, 84 (1), 479−490.(42) Singh, D. K.; Iyer, P. K.; Giri, P. K. Diameter Dependence ofInterwall Separation and Strain in Multiwalled Carbon NanotubesProbed by X-Ray Diffraction and Raman Scattering Studies. Diam.Relat. Mater. 2010, 19 (10), 1281−1288.(43) He, K.; Chen, N.; Wang, C.; Wei, L.; Chen, J. Method forDetermining Crystal Grain Size by X-Ray Diffraction. Cryst. Res.Technol. 2018, 53 (2), No. 1700157.(44) Malard, L. M.; Pimenta, M. A.; Dresselhaus, G.; Dresselhaus,M. S. Raman Spectroscopy in Graphene. Phys. Rep. 2009, 473 (5−6),51−87.(45) Reich, S.; Thomsen, C. Raman Spectroscopy of Graphite.Philos. Trans. R. Soc., A 2004, 362 (1824), 2271−2288.(46) Tsuji, R.; Masutani, H.; Haruyama, Y.; Niibe, M.; Suzuki, S.;Honda, S. I.; Matsuo, Y.; Heya, A.; Matsuo, N.; Ito, S. WaterElectrolysis Using Flame-Annealed Pencil-Graphite Rods. ACSSustain. Chem. Eng. 2019, 7 (6), 5681−5689.(47) Bokobza, L.; Bruneel, J. L.; Couzi, M. Raman SpectroscopicInvestigation of Carbon-Based Materials and Their Composites.Comparison between Carbon Nanotubes and Carbon Black. Chem.Phys. Lett. 2013, 590, 153−159.(48) Dresselhaus, M. S.; Jorio, A.; Souza Filho, A. G.; Saito, R.Defect Characterization in Graphene and Carbon Nanotubes UsingRaman Spectroscopy. Philos. Trans. R. Soc., A 2010, 368 (1932),5355−5377.(49) Marmur, A. The Lotus Effect: Superhydrophobicity andMetastability. Langmuir 2004, 20 (9), 3517−3519.(50) Wang, P.; Zhao, T.; Bian, R.; Wang, G.; Liu, H. RobustSuperhydrophobic Carbon Nanotube Film with Lotus Leaf MimeticMultiscale Hierarchical Structures. ACS Nano 2017, 11 (12), 12385−12391.(51) Yamamoto, M.; Nishikawa, N.; Mayama, H.; Nonomura, Y.;Yokojima, S.; Nakamura, S.; Uchida, K. Theoretical Explanation of theLotus Effect: Superhydrophobic Property Changes by Removal ofNanostructures from the Surface of a Lotus Leaf. Langmuir 2015, 31(26), 7355−7363.(52) Liu, Y.; Tang, J.; Wang, R.; Lu, H.; Li, L.; Kong, Y.; Qi, K.; Xin,J. H. Artificial Lotus Leaf Structures from Assembling CarbonNanotubes and Their Applications in Hydrophobic Textiles. J. Mater.Chem. 2007, 17 (11), 1071−1078.(53) Garg, R.; Rastogi, S. K.; Lamparski, M.; De La Barrera, S. C.;Pace, G. T.; Nuhfer, N. T.; Hunt, B. M.; Meunier, V.; Cohen-Karni,T. Nanowire-Mesh-Templated Growth of Out-of-Plane Three-Dimensional Fuzzy Graphene. ACS Nano 2017, 11 (6), 6301−6311.(54) Ikram, R.; Jan, B. M.; Pervez, S. A.; Papadakis, V. M.; Ahmad,W.; Bushra, R.; Kenanakis, G.; Rana, M. Recent Advancements of N-Doped Graphene for Rechargeable Batteries: A Review. Crystals 2020,10 (12), 1080.ACS Applied Energy Materials www.acsaem.org Articlehttps://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−1519515194https://doi.org/10.1021/acsami.3c10548?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsami.3c10548?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsami.3c10548?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1002/1521-3951(200101)223:1<29::AID-PSSB29>3.0.CO;2-Ohttps://doi.org/10.1002/1521-3951(200101)223:1<29::AID-PSSB29>3.0.CO;2-Ohttps://doi.org/10.1039/D1TA03307Ghttps://doi.org/10.1039/D1TA03307Ghttps://doi.org/10.1016/j.joule.2018.05.003https://doi.org/10.1016/j.joule.2018.05.003https://doi.org/10.1021/acsnano.2c04603?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsnano.2c04603?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.3390/molecules28041896https://doi.org/10.3390/molecules28041896https://doi.org/10.1021/acs.chemmater.5b03404?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.chemmater.5b03404?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.chemmater.5b03404?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1002/anie.201609080https://doi.org/10.1002/anie.201609080https://doi.org/10.1002/anie.201609080https://doi.org/10.1039/C9TA03346Ghttps://doi.org/10.1039/C9TA03346Ghttps://doi.org/10.1039/C9TA03346Ghttps://doi.org/10.1021/acsnano.3c08831?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsnano.3c08831?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acscatal.6b03497?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acscatal.6b03497?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acscatal.6b03497?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1149/2.0371807jeshttps://doi.org/10.1149/2.0371807jeshttps://doi.org/10.1149/2.0371807jeshttps://doi.org/10.1149/2.0371807jeshttps://doi.org/10.1149/2.0371807jeshttps://doi.org/10.1016/j.ijhydene.2019.08.132https://doi.org/10.1016/j.ijhydene.2019.08.132https://doi.org/10.1016/j.elecom.2019.02.018https://doi.org/10.1016/j.elecom.2019.02.018https://doi.org/10.1016/j.elecom.2019.02.018https://doi.org/10.1002/adma.202305844https://doi.org/10.1002/adma.202305844https://doi.org/10.1016/j.jallcom.2023.171367https://doi.org/10.1016/j.jallcom.2023.171367https://doi.org/10.1016/j.jallcom.2023.171367https://doi.org/10.1016/j.ijhydene.2024.01.338https://doi.org/10.1016/j.ijhydene.2024.01.338https://doi.org/10.1021/acsaem.4c02717?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsaem.4c02717?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1016/j.joule.2021.02.015https://doi.org/10.1016/j.joule.2021.02.015https://doi.org/10.1021/acsaem.1c01692?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsaem.1c01692?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsaem.1c01692?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1016/j.carbon.2007.03.038https://doi.org/10.1016/j.carbon.2007.03.038https://doi.org/10.1016/j.carbon.2021.01.022https://doi.org/10.1016/j.carbon.2021.01.022https://doi.org/10.1016/j.carbon.2021.01.022https://doi.org/10.1016/j.carbon.2014.12.030https://doi.org/10.1016/j.carbon.2014.12.030https://doi.org/10.1016/j.carbon.2014.12.030https://doi.org/10.1016/j.diamond.2010.06.003https://doi.org/10.1016/j.diamond.2010.06.003https://doi.org/10.1016/j.diamond.2010.06.003https://doi.org/10.1002/crat.201700157https://doi.org/10.1002/crat.201700157https://doi.org/10.1016/j.physrep.2009.02.003https://doi.org/10.1098/rsta.2004.1454https://doi.org/10.1021/acssuschemeng.8b04688?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acssuschemeng.8b04688?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1016/j.cplett.2013.10.071https://doi.org/10.1016/j.cplett.2013.10.071https://doi.org/10.1016/j.cplett.2013.10.071https://doi.org/10.1098/rsta.2010.0213https://doi.org/10.1098/rsta.2010.0213https://doi.org/10.1021/la036369u?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/la036369u?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsnano.7b06371?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsnano.7b06371?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsnano.7b06371?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.langmuir.5b00670?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.langmuir.5b00670?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acs.langmuir.5b00670?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1039/B613914Khttps://doi.org/10.1039/B613914Khttps://doi.org/10.1021/acsnano.7b02612?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.1021/acsnano.7b02612?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://doi.org/10.3390/cryst10121080https://doi.org/10.3390/cryst10121080www.acsaem.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-as(55) Mirzaeian, M.; Abbas, Q.; Ogwu, A.; Hall, P.; Goldin, M.;Mirzaeian, M.; Jirandehi, H. F. Electrode and Electrolyte Materials forElectrochemical Capacitors. Int. J. Hydrogen Energy 2017, 42 (40),25565−25587.(56) Ishii, T.; Kaburagi, Y.; Yoshida, A.; Hishiyama, Y.; Oka, H.;Setoyama, N.; Ozaki, J. I.; Kyotani, T. Analyses of Trace Amounts ofEdge Sites in Natural Graphite, Synthetic Graphite and High-Temperature Treated Coke for the Understanding of Their CarbonMolecular Structures. Carbon 2017, 125, 146−155.ACS Applied Energy Materials www.acsaem.org Articlehttps://doi.org/10.1021/acsaem.5c02078ACS Appl. Energy Mater. 2025, 8, 15186−1519515195https://doi.org/10.1016/j.ijhydene.2017.04.241https://doi.org/10.1016/j.ijhydene.2017.04.241https://doi.org/10.1016/j.carbon.2017.09.049https://doi.org/10.1016/j.carbon.2017.09.049https://doi.org/10.1016/j.carbon.2017.09.049https://doi.org/10.1016/j.carbon.2017.09.049www.acsaem.org?ref=pdfhttps://doi.org/10.1021/acsaem.5c02078?urlappend=%3Fref%3DPDF&jav=VoR&rel=cite-ashttps://www.cas.org/solutions/biofinder-discovery-platform?utm_campaign=GLO_ACD_STH_BDP_AWS&utm_medium=DSP_CAS_PAD&utm_source=Publication_ACSPubs