Lv Qingqing, Liu Di, Zhu Wei, Zhuang Zhongbin
State Key Lab of Organic-Inorganic Composites and Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Department of Pharmaceutical Engineering, School of Life and Health Sciences, HuZhou College, Huzhou, 313000, China.
Chemistry. 2024 Jul 2;30(37):e202400838. doi: 10.1002/chem.202400838. Epub 2024 Jun 14.
The hydroxide exchange membrane fuel cells (HEMFCs) are promising but lack of high-performance anode hydrogen oxidation reaction (HOR) electrocatalysts. The platinum group metals (PGMs) have the HOR activity in alkaline medium two to three orders of magnitude lower than those in acid, leading to the high required PGMs amount on anode to achieve high HEMFC performance. The mechanism study demonstrates the hydrogen binding energy of the catalyst determines the alkaline HOR kinetics, and the adsorbed OH and water on the catalyst surface promotes HOR. Iridium (Ir) has a unique advantage for alkaline HOR due to its similar hydrogen binding energy to Pt and enhanced adsorption of OH. However, the HOR activity of Ir/C is still unsatisfied in practical HEMFC applications. Further fine tuning the adsorption of the intermediate on Ir-based catalysts is of great significance to improve their alkaline HOR activity, which can be reasonably realized by structure design and composition regulation. In this concept, we address the current understanding about the alkaline HOR mechanism and summarize recent advances of Ir-based electrocatalysts with enhanced alkaline HOR activity. We also discuss the perspectives and challenges on Ir-based electrocatalysts in the future.
氢氧化物交换膜燃料电池（HEMFCs）前景广阔，但缺乏高性能的阳极氢氧化反应（HOR）电催化剂。铂族金属（PGMs）在碱性介质中的HOR活性比在酸性介质中低两到三个数量级，这导致在阳极需要大量的PGMs才能实现高的HEMFC性能。机理研究表明，催化剂的氢结合能决定了碱性HOR动力学，并且催化剂表面吸附的OH和水促进了HOR。铱（Ir）因其与Pt相似的氢结合能和增强的OH吸附而在碱性HOR方面具有独特优势。然而，在实际的HEMFC应用中，Ir/C的HOR活性仍不尽人意。进一步微调基于Ir的催化剂上中间体的吸附对于提高其碱性HOR活性具有重要意义，这可以通过结构设计和组成调控合理实现。在本概念中，我们阐述了目前对碱性HOR机理的理解，并总结了具有增强碱性HOR活性的基于Ir的电催化剂的最新进展。我们还讨论了未来基于Ir的电催化剂的前景和挑战。
