Assembling Ultrasmall Copper‐Doped Ruthenium Oxide Nanocrystals into Hollow Porous Polyhedra: Highly Robust Electrocatalysts for Oxygen Evolution in Acidic Media

Abstract Here, a facile and novel strategy for the preparation of Cu‐doped RuO 2 hollow porous polyhedra composed of ultrasmall nanocrystals through one‐step annealing of a Ru‐exchanged Cu‐BTC derivative is reported. Owing to the optimized surface configuration and altered electronic structure, the prepared catalyst displays a remarkable oxygen evolution reaction (OER) performance with low overpotential of 188 mV at 10 mA cm −2 in acidic electrolyte, an ultralow Tafel slope of 43.96 mV dec −1 , and excellent stability in durability testing for 10 000 cycles, and continuous testing of 8 h at a current density of 10 mA cm −2 . Density functional theory calculations reveal that the highly unsaturated Ru sites on the high‐index facets can be oxidized gradually and reduce the energy barrier of rate‐determining steps. On the other hand, the Cu dopants can alter the electronic structures so as to further improve the intrinsic OER activity.