Preparation of Two‐Dimensional Bi‐doped RuO 2 Nanosheets for High‐performance Acidic Oxygen Evolution Reaction

Although ruthenium‐based oxide (RuO 2 ) is an active catalyst for the acidic oxygen evolution reaction (OER), it suffers from lattice oxygen oxidation and dissolution of active sites under high current densities or prolonged operation, leading to a tradeoff between stability and activity. These limitations hinder its large‐scale application and impede the commercialization of proton exchange membrane water electrolyzers (PEMWE). Recent studies have demonstrated that doping with transition metals can effectively modulate the electronic structure of RuO 2 and enhance its catalytic properties. In this study, we introduced bismuth (Bi) atoms at varying ratios into the RuO 2 lattice via a sol–gel method, successfully synthesizing a series of Bi x Ru 1‐ x O 2 ( x = 0.02, 0.03, 0.05, 0.07) catalysts. Among these, the Bi 0.02 Ru 0.98 O 2 nanocatalyst exhibited outstanding performance, requiring an overpotential of only 171 mV to achieve a current density of 10 mA cm −2 in acidic OER, significantly lower than that of commercial RuO 2 . Moreover, it demonstrated exceptional stability, maintaining activity over 24 h of continuous operation.