Optimizing Hydrogen and Hydroxyl Adsorption over Ru/WO2.9 Metal/Metalloid Heterostructure Electrocatalysts for Highly Efficient and Stable Hydrogen Oxidation Reactions in Alkaline Media

The development of high-performance, stable and platinum-free electrocatalysts for the hydrogen oxidation reaction (HOR) in alkaline media is crucial for the commercial application of anion exchange membrane fuel cells (AEMFCs). Ruthenium, as an emerging HOR electrocatalyst with a price advantage over platinum, still needs to solve the problems of low intrinsic activity and easy oxidation. Herein, Ru nanoparticles are anchored on the oxygen-vacancy-rich metalloid WO_2.9 by interfacial engineering to create abundant and efficient Ru and WO_2.9 interfacial active sites for accelerated HOR in alkaline media. Ru/WO_2.9/C displays excellent catalytic activity with mass activity (8.29 A mg_NM ^-1) and specific activity (1.32 mA cm_NM ^-2), which are 2.5/3.3 and 21.8/8.3 times that of PtRu/C and Pt/C, respectively. Moreover, Ru/WO_2.9/C exhibits excellent CO tolerance and operational stability. Experimental and theoretical studies reveal that the improved charge transfer from Ru to WO_2.9 in the metal/metalloid heterostructure significantly tune the electronic structure of Ru sites and optimize the hydrogen binding energy (HBE) of Ru. While, WO_2.9 provides abundant hydroxyl adsorption sites. Therefore, the equilibrium adsorption of hydrogen and hydroxyl at the interface of Ru/WO_2.9 will be realized, and the oxidation of metal Ru would be avoided, thereby achieving excellent HOR activity and durability.