Pb‐Modified Ultrathin RuCu Nanoflowers for Active, Stable, and CO‐resistant Alkaline Electrocatalytic Hydrogen Oxidation

Abstract CO poisoning of Pt group metal (PGM) catalysts is a chronic problem for hydrogen oxidation reaction (HOR), the anodic reaction of hydroxide exchange membrane fuel cell (HEMFC) for converting H 2 to electric energy in sustainable manner. We demonstrate here an ultrathin Ru‐based nanoflower modified with Pb (PbRuCu NF) as an active, stable, and CO‐resistant catalyst for alkaline HOR. Mechanism studies show that the presence of Pb can weaken the adsorption of *H, strengthen *OH adsorption to facilitate CO oxidation, as a result of significantly enhanced HOR activity and improved CO tolerance. Furthermore, in situ electrochemical attenuated total reflection surface‐enhanced infrared absorption spectroscopy (ATR‐SEIRAS) suggests that Pb acts as oxygen‐rich site to regulate the behavior of the linear CO adsorption. The optimized Pb 1.04 ‐Ru 92 Cu 8 /C displays a mass activity and specific activity of 1.10 A mg Ru −1 and 5.55 mA cm −2 , which are ≈10 and ≈31 times higher than those of commercial Pt/C. This work provides a facile strategy for the design of Ru‐based catalyst with high activity and strong CO‐resistance for alkaline HOR, which may promote the fundamental researches on the rational design of functional catalysts.