Tailoring Interfacial Chemistry of Defective Carbon-Supported Ru Catalyst Toward Efficient and CO-Tolerant Alkaline Hydrogen Oxidation Reaction

The ability to create highly active and CO-tolerant platinum-free catalysts toward alkaline hydrogen oxidation reaction (HOR) represents a significant endeavor to enable commercialization of alkaline fuel cells. This, however, remains a grand challenge. Herein, a robust defective-carbon-supported Ru catalyst (denoted as Ru@C) is crafted to achieve efficient and CO-tolerant HOR in alkaline media via delicately tailoring interfacial chemistry of catalyst. Notably, the degree of defects in the carbon support is the key to tune the interface chemistry. An integrated experimental and density functional theory calculations study demonstrates that the favorable interfacial chemical interaction between Ru and carbon support controlled by the covalently bonded RuOC redistributes the d electrons of Ru and downshiftsits d-band center, which in turn weakens the hydrogen adsorption and suppresses the Ru 4d -> CO 2 pi* back donation. Consequently, the optimized Ru@C catalyst renders a 6.6-fold enhancement in mass activity (@25 mV) for alkaline HOR over the conventional Ru/C counterpart, which also outperforms the state-of-the-art catalysts. Intriguingly, the catalyst can tolerate 20 000 ppm CO, far exceeding that of commercial Pt/C and PtRu/C catalysts. This work elucidates the correlation between precisely tailored interfacial chemistry and HOR performance, and is expected to further enlighten the design of advanced catalysts.