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Enhancing the durability of catalysts is of critical significance to industrialize green hydrogen production. Herein, a novel active site in situ refreshing strategy is proposed and demonstrated to fabricate highly active and ultra‐durable hydrogen evolution reaction (HER) electro‐catalytic material by HER activation. Briefly, a composite catalytic material is synthesized, which features Ni(PO3)2 active sites being embedded inside the amorphous Mo compound matrix (named NiMoO‐P). The Mo compound matrix undergoes gradual dissolution during HER followed by a dynamic equilibrium between the dissolution and deposition of the amorphous matrix. This process promotes the continuous exposure of insoluble Ni(PO3)2 and Ni2P partially converted from Ni (PO3) 2 in situ on the surface during HER activation. Thus, activated catalyst exhibits excellent HER performance featuring an extremely high current density of 1500 mA cm−2 at a rather low overpotential of 340 mV, and more attractively, an ultra‐long durability for hydrogen evolution for at least 1000 h at an industrial‐applicable current density of 900 mA cm−2. The mechanisms for the especially high HER performance are attributed to the exposure and continuous refreshing of Ni(PO3)2 and the in situ formed Ni2P during the HER process based on the DFT calculations and quasi‐in situ Raman spectroscopic monitoring. [ABSTRACT FROM AUTHOR]

A novel Zn−Fe flow battery featuring an Fe3+ reduction reaction (Fe3+RR)‐coupled zinc oxidation, and an Fe2+ oxidation reaction (Fe2+OR)‐coupled hydrogen evolution reaction (HER) system as well, was established. This battery is capable of driving two Fe2+OR‐coupled HER systems in series based on the above Fe2+/Fe3+ cycling, for efficient self‐powered hydrogen evolution. Meanwhile, this Fe2+/Fe3+ cycling enables the preparation of a multifunctional catalyst, Pt‐3@SXNS (siloxene nanosheet), by the Fe2+OR‐promoted dispersion of Pt nanoparticles on SXNS; alternatively, this support could be obtained by Fe3+RR‐assisted exfoliation using Fe3+ from the anolyte of Fe2+OR‐coupled HER. The Pt‐3@SXNS catalyst exhibits excellent catalytic activities toward Fe3+RR in the Zn−Fe flow battery, HER, and Fe2+OR in the electrolyzer, which is attributed to the strong electronic interaction between Pt and Si. This work offers a new strategy for energy storage and low‐cost hydrogen production from acidic wastewater. [ABSTRACT FROM AUTHOR]

A novel Zn−Fe flow battery featuring an Fe3+ reduction reaction (Fe3+RR)‐coupled zinc oxidation, and an Fe2+ oxidation reaction (Fe2+OR)‐coupled hydrogen evolution reaction (HER) system as well, was established. This battery is capable of driving two Fe2+OR‐coupled HER systems in series based on the above Fe2+/Fe3+ cycling, for efficient self‐powered hydrogen evolution. Meanwhile, this Fe2+/Fe3+ cycling enables the preparation of a multifunctional catalyst, Pt‐3@SXNS (siloxene nanosheet), by the Fe2+OR‐promoted dispersion of Pt nanoparticles on SXNS; alternatively, this support could be obtained by Fe3+RR‐assisted exfoliation using Fe3+ from the anolyte of Fe2+OR‐coupled HER. The Pt‐3@SXNS catalyst exhibits excellent catalytic activities toward Fe3+RR in the Zn−Fe flow battery, HER, and Fe2+OR in the electrolyzer, which is attributed to the strong electronic interaction between Pt and Si. This work offers a new strategy for energy storage and low‐cost hydrogen production from acidic wastewater. [ABSTRACT FROM AUTHOR]