Shi Hongda, Yang Yang, Meng Pin, Yang Jiahe, Zheng Wei, Wang Pengcheng, Zhang Yunlong, Chen Xingyan, Cheng Zhiyu, Zong Cichang, Wang Dongdong, Chen Qianwang
Hefei National Research Center for Physical Sciences at the Microscale and Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China.
The High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, China.
J Am Chem Soc. 2024 Jun 5. doi: 10.1021/jacs.4c03622.
The activity of Ru-based alkaline hydrogen oxidation reaction (HOR) electrocatalysts usually decreases rapidly at potentials higher than 0.1 V ( a reversible hydrogen electrode (RHE)), which significantly limits the lifetime of fuel cells. It is found that this phenomenon is caused by the overadsorption of the O species due to the overcharging of Ru nanoparticles at high potentials. Here, MnO(OH) clusters-modified Ru nanoparticles (MnO(OH)@Ru/C) were prepared to promote charge transfer from overcharged Ru nanoparticles to MnO(OH) clusters. MnO(OH)@Ru/C exhibits high HOR activity and stability over a wide potential range of 0-1.0 V. Moreover, a hydroxide exchange membrane fuel cell with a MnO(OH)@Ru/C anode delivers a high peak power density of 1.731 W cm, much superior to that of a Pt/C anode. X-ray absorption fine structure (XAFS) analysis and density functional theory (DFT) calculations reveal that Mn in MnO(OH) clusters could receive more electrons from overcharged Ru at higher potentials and significantly decrease the overadsorption of the O species on Ru, thus permitting the HOR on Ru to proceed at high potentials. This study provides guidance for the design of alkaline HOR catalysts without activity decay at high potentials.
钌基碱性氢氧化反应（HOR）电催化剂的活性通常在高于0.1 V（可逆氢电极（RHE））的电位下迅速降低，这显著限制了燃料电池的寿命。研究发现，这种现象是由于在高电位下钌纳米颗粒过度充电导致O物种过度吸附所致。在此，制备了MnO(OH)簇修饰的钌纳米颗粒（MnO(OH)@Ru/C），以促进从过度充电的钌纳米颗粒到MnO(OH)簇的电荷转移。MnO(OH)@Ru/C在0-1.0 V的宽电位范围内表现出高HOR活性和稳定性。此外，具有MnO(OH)@Ru/C阳极的氢氧化物交换膜燃料电池提供了1.731 W cm的高峰值功率密度，远优于Pt/C阳极。X射线吸收精细结构（XAFS）分析和密度泛函理论（DFT）计算表明，MnO(OH)簇中的Mn在较高电位下可以从过度充电的Ru接收更多电子，并显著降低O物种在Ru上的过度吸附，从而使Ru上的HOR在高电位下进行。本研究为设计在高电位下无活性衰减的碱性HOR催化剂提供了指导。
