Two-Dimensional Self-assembly of Unconventional fcc Ru<sub>3</sub>Ir Nanocrystals for Efficient and Robust Acidic Water Oxidation
Jinchang Fan, Yajing Mu, Xin Ge, Lei Zhang, Weiwei Li, Hongliang Dong, Dewen Wang, Wei Zhang, Jingyuan Ma, Weitao Zheng, Xiaoqiang Cui
Abstract
Acidic oxygen evolution reaction (OER) catalysts face the fundamental challenge of the trade-off between activity and durability that has not yet been well addressed. Herein, we integrate high activity of nanoparticles and good stability of bulk materials into a “macro-nano” catalyst through two-dimensional self-assembling of unconventional fcc phase Ru 3 Ir nanocrystals. Such catalysts deliver a low overpotential of 190 mV at 10 mA cm –2 and stably maintain this over 400 h or 10,000 potential cycles for acidic OER, surpassing previously reported metallic-based catalysts. Operando X-ray absorption spectroscopy and DFT calculations reveal that the high activity is derived from self-reconstructed surface Ru 3 IrO x species during OER, which are electronically modulated by the fcc-Ru 3 Ir substrate and lower the energy barrier of the potential-determining O* → OOH* step. Control experiments reveal that two-dimensional self-assembled structures significantly enhance the corrosion resistance ability of 2D fcc-Ru 3 Ir by inhibiting the excessive dissolution of surface Ru 3 IrO x species during the OER process. This nano-to-macro strategy may provide a guideline for designing efficient and robust catalysts for acidic OER and beyond.