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

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 (Had) and hydroxyl (OHad). To address this concern, a strongly coupled multisite electrocatalyst with highly active cluster-scale ruthenium-tungsten oxide (Ru-WOx) interface, which could eliminate the competitive adsorption phenomenon and achieve high coverage of OHad and Had at Ru and WOx domains, respectively, is designed. The experimental and theoretical results demonstrate that WOx domain functions as a proton sponge to perpetually accommodate the activated hydrogen species that spillover from the adjacent Ru domain, and the resulting WO-Had species are readily coupled with Ru-OHad 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−2 with a low anode catalyst loading of 0.05 mgRu cm−2 and outstanding durability (negligible voltage decay over 80-h operation at 500 mA cm−2). This work offers completely new insights into understanding the alkaline HOR mechanism and designing advanced anode catalysts for AEMFCs.