Re-Looking into the Active Moieties of Metal X-ides (X- = Phosph-, Sulf-, Nitr-, and Carb-) Toward Oxygen Evolution Reaction |
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Authors: | Ruipeng Luo Zhengyi Qian Lixin Xing Chunyu Du Geping Yin Shenlong Zhao Lei Du |
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Affiliation: | 1. School of Chemistry and Chemical Engineering, Harbin Institute of Technology, Harbin, 150001 China;2. School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales, 2006 Australia |
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Abstract: | Non-precious metal-based catalysts for oxygen evolution reaction (OER) have been extensively studied, among which the transition metal X-ides (including phosph-ides, sulf-ides, nitr-ides, and carb-ides) materials are emerging as promising candidates to replace the benchmark Ir/Ru-based materials in alkaline media. However, it is controversial whether the metal Xides host the real active sites since these metal Xides are thermodynamically unstable under a harsh OER environment—it has been reported that the initial metal Xides can be electrochemically oxidized and transformed into corresponding oxides and (oxy)hydroxides. Therefore, the metal Xides are argued as “pre-catalysts”; the electrochemically formed oxides and (oxy)hydroxides are believed as the real active moieties for OER. Herein, the recent advances in understanding the transformation behavior of metal Xides during OER are re-looked; importantly, hypotheses are provided to understand why the electrochemically formed oxides and (oxy)hydroxides catalysts derived from metal Xides are superior for OER to the as-prepared metal oxides and (oxy)hydroxides catalysts. |
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Keywords: | active sites metal xides non-precious metal catalysts oxygen evolution reaction pre-catalysts |
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