Cluster-Scale Multisite Interface Reinforces Ruthenium-Based Anode Catalysts for Alkaline Anion Exchange Membrane Fuel Cells.

Zheng, Xiaozhong; Zhang, Shuxin; Zheng, Xinying; Zhuang, Zhongbin; Gao, Mingxia; Liu, Yongfeng; Pan, Hongge; Sun, Wenping · Adv Mater · 2025

basic_science · Level V

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Abstract

Ruthenium (Ru) is a more cost-effective alternative to platinum anode catalysts for alkaline anion-exchange membrane fuel cells (AEMFCs), but suffers from severe competitive adsorption of hydrogen (H<sub>ad</sub>) and hydroxyl (OH<sub>ad</sub>). To address this concern, a strongly coupled multisite electrocatalyst with highly active cluster-scale ruthenium-tungsten oxide (Ru-WO<sub>x</sub>) interface, which could eliminate the competitive adsorption phenomenon and achieve high coverage of OH<sub>ad</sub> and H<sub>ad</sub> at Ru and WO<sub>x</sub> domains, respectively, is designed. The experimental and theoretical results demonstrate that WO<sub>x</sub> domain functions as a proton sponge to perpetually accommodate the activated hydrogen species that spillover from the adjacent Ru domain, and the resulting WO-H<sub>ad</sub> species are readily coupled with Ru-OH<sub>ad</sub> at the heterointerface to finish the hydrogen oxidation reaction with faster kinetics via the thermodynamically favorable Tafel-Volmer mechanism. The AEMFC delivers a high peak power density of 1.36 W cm<sup>-2</sup> with a low anode catalyst loading of 0.05 mg<sub>Ru</sub> cm<sup>-2</sup> and outstanding durability (negligible voltage decay over 80-h operation at 500 mA cm<sup>-2</sup>). This work offers completely new insights into understanding the alkaline HOR mechanism and designing advanced anode catalysts for AEMFCs.