Engineering Ru-RuO2 interface with regulated hydroxyl adsorption towards efficient and CO-tolerant hydrogen oxidation reaction

Owning to the similar hydrogen binding strength and lower price, Ru is considered as a promising substitute for Pt towards hydrogen oxidation reaction (HOR). However, the unoptimized intermediate adsorption on metallic Ru site makes Ru/C inferior to Pt/C benchmark in terms of lower HOR activity as well as CO tolerance. Herein, we developed a novel competitive adsorption strategy through the construction of Ru-RuO2 interface to enhance alkaline HOR performance and CO tolerance simultaneously. Specifically, the competitive adsorption of OH* between Ru and RuO2 could alleviate the strong affinity of OH* on Ru, which would promote both alkaline HOR and CO oxidation significantly. Besides, the engineered interface structure optimized hydrogen binding energy (HBE) via electronic modulation effect as well. Benefitting from these attributes, the as-designed Ru-RuO2/C catalyst exhibits remarkable HOR performance with a mass activity of 2.50 A mg-1 @ 50 mV, which is 10 and 5 times higher than that of Ru/C and commercial Pt/C, respectively. More strikingly, Ru-RuO2/C performs unprecedented anti-poisoning capacity towards CO, with only a small decrease of 6.9 % in the limiting current density in the presence of 30,000 ppm CO, far surpassing the commercial Pt/C catalyst. This work not only provides a cost-effective and robust HOR catalyst in alkaline media, but also opens up a new avenue to tailor the adsorption-desorption properties of intermediates on heterogenous electrocatalyst.