Heterophase junction engineering-induced Co spin-state modulation of CoSe2 for large-current hydrogen evolution reaction

Xu, BC, Miao, YP, Mao, MQ, Li, DL, Xie, S, Jin, WH, Xiao, S, Wen, J, Abd-Allah, Z ORCID: https://orcid.org/0000-0003-1016-014X, Liu, ZT, Peng, X and Chu, PK (2024) Heterophase junction engineering-induced Co spin-state modulation of CoSe2 for large-current hydrogen evolution reaction. Rare Metals, 43 (6). pp. 2660-2670. ISSN 1001-0521

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Abstract

Efficient electrocatalysts are vital to large-current hydrogen production in commercial water splitting for green energy generation. Herein, a novel heterophase engineering strategy is described to produce polymorphic CoSe2 electrocatalysts. The composition of the electrocatalysts consisting of both cubic CoSe2 (c-CoSe2) and orthorhombic CoSe2 (o-CoSe2) phases can be controlled precisely. Our results demonstrate that junction-induced spin-state modulation of Co atoms enhances the adsorption of intermediates and accelerates charge transfer resulting in superior large-current hydrogen evolution reaction (HER) properties. Specifically, the CoSe2-based heterophase catalyst with the optimal c-CoSe2 content requires an overpotential of merely 240 mV to achieve 1,000 mA·cm−2 as well as a Tafel slope of 50.4 mV·dec−1. Furthermore, the electrocatalyst can maintain a large current density of 1,500 mA·cm−2 for over 320 h without decay. The results reveal the advantages and potential of heterophase junction engineering pertaining to design and fabrication of low-cost transition metal catalysts for large-current water splitting.