Article B-site substitution-induced band edge shifts in perovskite-type Cu(Nb,Ta)O3 solid solutions for visible-light-driven hydrogen evolution

Haocong Wang ; Chihiro Takahashi ; Xuemeng Guo ; Shunya Okada ; Hajime Suzuki ORCID ; Daiming Tang SAMURAI ORCID ; Wei Yi ORCID ; Ikuya Yamada ; Xiaojuan Liu ORCID ; Ryu Abe ORCID ; Koji Fujita ORCID

Wang_JMC_2025.pdf
Download file (949 KB)
Download as zip (854 KB)
Collection

Citation
Haocong Wang, Chihiro Takahashi, Xuemeng Guo, Shunya Okada, Hajime Suzuki, Daiming Tang, Wei Yi, Ikuya Yamada, Xiaojuan Liu, Ryu Abe, Koji Fujita. B-site substitution-induced band edge shifts in perovskite-type Cu(Nb,Ta)O3 solid solutions for visible-light-driven hydrogen evolution. Journal of Materials Chemistry C. 2025, 13 (39), 20146-20155. https://doi.org/10.1039/d5tc02066b

Description:

(abstract)

The rational design of photocatalysts with precise bandgap and band-edge control is crucial for achieving the visible-light-driven conversion of solar to hydrogen. This study demonstrates a novel strategy for band-edge engineering through B-site cation substitution and symmetry evolution in Cu (3d10)-based perovskites. Substitution of Ta5+ (5d0) for Nb5+ (4d0) in CuNbO3 induces sequential phase transitions (Pc–R3c–R[3 with combining macron]c), accompanied by systematic bandgap modulation from 1.57 to 2.23 eV. The R[3 with combining macron]c CuTaO3 phase exhibits a much higher conduction band (−0.90 V vs. standard hydrogen electrode) than the H+/H2 potential and a slightly lower valence band than the O2/H2O potential. Visible-light-driven hydrogen evolution occurs efficiently on CuTaO3 with Ru cocatalyst, in the presence of S2−/SO32− sacrificial agents. Our experiments and first-principles calculations reveal that the Ta-for-Nb-substitution widens the bandgap by lowering the valence band maximum via weakened Cu–O hybridization, while simultaneously elevating the conduction band minimum via Ta 5d orbital contributions. The inherent bandgap-narrowing tendency of structural evolution from polar Pc to centrosymmetric R[3 with combining macron]c symmetry is attenuated by Ta substitution-induced elongation of Cu–O bonds. The interplay between B-site cation engineering and symmetry-induced electronic degeneration establishes a materials design paradigm for visible-light-driven photocatalysis, demonstrating how to enable targeted bandgap optimization by coupling orbital-level modifications and phase transition.

Rights:

Keyword: hydrogen evolution, perovskite, substitution-induced band edge shifts

Date published: 2025-08-14

Publisher: Royal Society of Chemistry (RSC)

Journal:

  • Journal of Materials Chemistry C (ISSN: 20507526) vol. 13 issue. 39 p. 20146-20155

Funding:

  • Mitsubishi Foundation
  • Izumi Science and Technology Foundation
  • Japan Society for the Promotion of Science F21750
  • Japan Society for the Promotion of Science JP21H04619
  • Japan Society for the Promotion of Science JP22K04686
  • Japan Society for the Promotion of Science JP22KF0195
  • Japan Society for the Promotion of Science JP23K23043
  • Japan Society for the Promotion of Science JP24K21688
  • Iwatani Naoji Foundation
  • Nippon Sheet Glass Foundation for Materials Science and Engineering

Manuscript type: Author's version (Submitted manuscript)

MDR DOI: https://doi.org/10.48505/nims.6001

First published URL: https://doi.org/10.1039/d5tc02066b

Related item:

Other identifier(s):

Contact agent:

Updated at: 2025-12-12 16:30:04 +0900

Published on MDR: 2025-12-12 16:26:08 +0900

Filename Size
Filename Wang_JMC_2025.pdf (Thumbnail)
application/pdf 		Size 949 KB Detail