Decoupling fast hydrogen oxidation reaction on a tandem electrocatalyst.

Guo, Wei; Zhao, Guoqiang; Sun, Ziang; Zhang, Bingxing; Xin, Dongyue; Gao, Mingxia; Liu, Yongfeng; Zhuang, Zhongbin et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

The hydrogen oxidation reaction (HOR) shows fast kinetics in proton exchange membrane fuel cells (PEMFCs), and has not drawn intense attention. Here, we propose a tandem electrocatalysis concept, decoupling HOR on two independent active sites for accelerated kinetics. As a proof-of-concept application, a Ru-based tandem HOR catalyst is designed, with Ru nanoclusters decorated with Pt single atoms. Experimental and theoretical studies suggest that H<sub>2</sub> dissociation occurs at Ru sites, and then the produced H species migrate to Pt sites followed by the desorption of H<sup>+</sup>. The strong Ru-H interaction promotes the H<sub>2</sub> dissociation step, while the optimum Pt-H interaction ensures the fast desorption, thereby substantially enhancing the HOR kinetics. In H<sub>2</sub>-O<sub>2</sub> fuel cells, this catalyst enables a peak power density of 1.91 W cm<sup>-2</sup> and a high anodic mass activity of 23.12 A mg<sup>-1</sup> at 0.9 V<sub>iR-free</sub> with an ultralow noble metal loading of 5 μg cm<sup>-2</sup>. This work advances the development of low-cost anode catalysts for fuel cells and provides more insight into understanding hydrogen electrocatalysis.