Lebedev Dmitry, Ezhov Roman, Heras-Domingo Javier, Comas-Vives Aleix, Kaeffer Nicolas, Willinger Marc, Solans-Monfort Xavier, Huang Xing, Pushkar Yulia, Copéret Christophe
Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1-5, CH-8093 Zurich, Switzerland.
Department of Physics and Astronomy, Purdue University, West Lafayette, Indiana 47907, United States.
ACS Cent Sci. 2020 Jul 22;6(7):1189-1198. doi: 10.1021/acscentsci.0c00604. Epub 2020 Jul 1.
Heterogeneous catalysts in the form of atomically dispersed metals on a support provide the most efficient utilization of the active component, which is especially important for scarce and expensive late transition metals. These catalysts also enable unique opportunities to understand reaction pathways through detailed spectroscopic and computational studies. Here, we demonstrate that atomically dispersed iridium sites on indium tin oxide prepared via surface organometallic chemistry display exemplary catalytic activity in one of the most challenging electrochemical processes, the oxygen evolution reaction (OER). X-ray absorption studies revealed the formation of Ir=O intermediate under OER conditions with an Ir-O distance of 1.83 Å. Modeling of the reaction mechanism indicates that Ir=O is likely a catalyst resting state, which is subsequently oxidized to Ir enabling fast water nucleophilic attack and oxygen evolution. We anticipate that the applied strategy can be instrumental in preparing and studying a broad range of atomically dispersed transition metal catalysts on conductive oxides for (photo)electrochemical applications.
负载型原子分散金属形式的多相催化剂能够最有效地利用活性成分，这对于稀缺且昂贵的晚期过渡金属尤为重要。这些催化剂还为通过详细的光谱和计算研究来理解反应途径提供了独特的机会。在此，我们证明，通过表面有机金属化学方法制备的氧化铟锡上的原子分散铱位点，在最具挑战性的电化学过程之一——析氧反应（OER）中表现出优异的催化活性。X射线吸收研究表明，在OER条件下形成了Ir=O中间体，Ir-O距离为1.83 Å。反应机理建模表明，Ir=O可能是催化剂的静止状态，随后被氧化为Ir，从而使水能够快速进行亲核攻击并析氧。我们预计，所应用的策略有助于制备和研究用于（光）电化学应用的、在导电氧化物上的多种原子分散过渡金属催化剂。
