Engineering high-density microcrystalline boundary with V-doped RuO2 for high-performance oxygen evolution in acid
Han Wu, Zhanzhao Fu, Jiangwei Chang, Zhongjian Hu, Jiansheng Li, Siyang Wang, Jingkun Yu, Xue Yong, Geoffrey I. N. Waterhouse, Zhiyong Tang, Junbiao Chang, Siyu Lu, Junbiao Chang, Siyu Lu
Abstract
Designing efficient acidic oxygen evolution catalysts for proton exchange membrane water electrolyzers is challenging due to a trade-off between activity and stability. In this work, we construct high-density microcrystalline grain boundaries (GBs) with V-dopant in RuO2 matrix (GB-V-RuO2). Our theoretical and experimental results indicate this is a highly active and acid-resistant OER catalyst. Specifically, the GB-V-RuO2 requires low overpotentials of 159, 222, and 300 mV to reach 10, 100, and 1500 mA cm-2geo in 0.5 M H2SO4, respectively. Operando EIS, ATR-SEIRAS FTIR and DEMS measurements reveal the importance of GBs in stabilizing lattice oxygen and thus inhibiting the lattice oxygen mediated OER pathway. As a result, the adsorbate evolution mechanism pathway becomes dominant, even at high current densities. Density functional theory analyses confirm that GBs can stabilize V dopant and that the synergy between them modulates the electronic structure of RuO2, thus optimizing the adsorption of OER intermediate species and enhancing electrocatalyst stability. Our work demonstrates a rational strategy for overcoming the traditional activity/stability dilemma, offering good prospects of developing high-performance acidic OER catalysts. Designing efficient and stable acidic oxygen evolution catalysts is challenging. Here, the authors construct high-density grain boundaries in V-doped RuO2 to tune its electronic structure and boost stability, addressing the activity/stability trade-off in proton exchange membrane water electrolyzers.