水氧化反应(或析氧反应,OER)在通过水分解的绿色制氢中起着至关重要的作用,电化学CO2还原,和固氮。四电子和四质子转移OER过程涉及多个反应中间体和基本步骤,导致动力学缓慢;因此,高过电位是驱动反应所必需的。在不同的水分解电解槽中,质子交换膜式电解槽具有更大的优势,但其阳极催化剂仅限于铱基材料。铱催化剂由于其对酸性OER的平衡活性和稳定性,近年来得到了广泛的研究,并取得了许多令人兴奋的进展迹象。在这次审查中,介绍了水溶液中铱物种的表面和块状Pourbaix图。铱基催化剂,包括金属或氧化物,无定形或结晶,单晶,原子分散或纳米结构,和OER的铱化合物,然后详细阐述。活跃网站的最新进展,反应中间体,反应动力学,并总结了基本步骤。最后,讨论了铱酸性OER催化剂的未来研究方向。
The water oxidation reaction (or oxygen evolution reaction, OER) plays a critical role in green hydrogen production via water splitting, electrochemical CO2 reduction, and nitrogen fixation. The four-electron and four-proton transfer OER process involves multiple reaction intermediates and elementary steps that lead to sluggish kinetics; therefore, a high overpotential is necessary to drive the reaction. Among the different water-splitting electrolyzers, the proton exchange membrane type electrolyzer has greater advantages, but its anode catalysts are limited to iridium-based materials. The iridium catalyst has been extensively studied in recent years due to its balanced activity and stability for acidic OER, and many exciting signs of progress have been made. In this review, the surface and bulk Pourbaix diagrams of iridium species in an aqueous solution are introduced. The iridium-based catalysts, including metallic or oxides, amorphous or crystalline, single crystals, atomically dispersed or nanostructured, and iridium compounds for OER, are then elaborated. The latest progress of active sites, reaction intermediates, reaction kinetics, and elementary steps is summarized. Finally, future research directions regarding iridium catalysts for acidic OER are discussed.