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Dual-atom catalytic sites on conductive substrates offer a promising opportunity for accelerating the kinetics of multistep hydrogen and oxygen evolution reactions (HER and OER, respectively). Using MXenes as substrates is a promising strategy for depositing those dual-atom electrocatalysts, if the efficient surface anchoring strategy ensuring metal-substrate interactions and sufficient mass loading is established. We introduce a surface-modification strategy of MXene substrates by preadsorbing L-tryptophan molecules, which enabled attachment of dual-atom Co/Ni electrocatalyst at the surface of Ti3C2Tx by forming N-Co/Ni-O bonds, with mass loading reaching as high as 5.6 wt %. The electron delocalization resulting from terminated O atoms on MXene substrates, N atoms in L-tryptophan anchoring moieties, and catalytic metal atoms Co and Ni provides an optimal adsorption strength of intermediates and boosts the HER and OER kinetics, thereby notably promoting the intrinsic activity of the electrocatalyst. CoNi-Ti3C2Tx electrocatalyst displayed HER and OER overpotentials of 31 and 241 mV at 10 mA cm-2, respectively. Importantly, the CoNi-Ti3C2Tx electrocatalyst also exhibited high operational stability for both OER and HER over 100 h at an industrially relevant current density of 500 mA cm-2. Our study provided guidance for constructing dual-atom active metal sites on MXene substrates to synergistically enhance the electrochemical efficiency and stability of the energy conversion and storage systems.

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  This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Nano, copyright © 2024 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsnano.3c09639

Keyword: dual-atom electrocatalyst, MXene substrate, oxygen evolution reaction, hydrogen evolution reaction, anchor L-tryptophan molecules

Date published: 2024-02-06

Publisher: American Chemical Society (ACS)

Journal:

• ACS Nano (ISSN: 1936086X) vol. 18 issue. 5 p. 4256-4268

Funding:

• National Natural Science Foundation of China U23A200767
• National Natural Science Foundation of China 52177220
• Hong Kong Scholar Program XJ2020001
• Qatar Research Development and Innovation Council ARG01-0524-230315

Manuscript type: Author's version (Accepted manuscript)

MDR DOI: https://doi.org/10.48505/nims.4686

First published URL: https://doi.org/10.1021/acsnano.3c09639

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Updated at: 2025-01-25 08:30:15 +0900

Published on MDR: 2025-01-25 08:30:16 +0900