Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), EPFL-ISIC-LSCI, BCH 3305, Lausanne CH 1015, Switzerland.
Nat Commun. 2016 Aug 9;7:12324. doi: 10.1038/ncomms12324.
Efficient oxygen-evolution reaction catalysts are required for the cost-effective generation of solar fuels. Metal selenides have been reported as promising oxygen-evolution catalysts; however, their active forms are yet to be elucidated. Here we show that a representative selenide catalyst, nickel selenide, is entirely converted into nickel hydroxide under oxygen-evolution conditions. This result indicates that metal selenides are unstable during oxygen evolution, and the in situ generated metal oxides are responsible for their activity. This knowledge inspired us to synthesize nanostructured nickel iron diselenide, a hitherto unknown metal selenide, and to use it as a templating precursor to a highly active nickel iron oxide catalyst. This selenide-derived oxide catalyses oxygen evolution with an overpotential of only 195 mV for 10 mA cm(-2). Our work underscores the importance of identifying the active species of oxygen-evolution catalysts, and demonstrates how such knowledge can be applied to develop better catalysts.
高效的氧析出反应催化剂对于经济有效地生成太阳能燃料是必需的。金属硒化物已被报道为很有前途的氧析出催化剂；然而，其活性形式仍有待阐明。在这里，我们表明，一种代表性的硒化物催化剂，即硒化镍，在氧析出条件下完全转化为氢氧化镍。这一结果表明，金属硒化物在氧析出过程中是不稳定的，而原位生成的金属氧化物是其活性的原因。这一认识启发我们合成了纳米结构的镍铁二硒化物，这是一种迄今未知的金属硒化物，并将其用作一种模板前体，以制备一种高活性的镍铁氧化物催化剂。这种硒化物衍生的氧化物在 10 mA cm(-2)的电流密度下，仅需 195 mV 的过电势即可催化氧析出反应。我们的工作强调了确定氧析出催化剂的活性物种的重要性，并展示了如何将这方面的知识应用于开发更好的催化剂。
