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

摘要

The ability to create highly active and CO-tolerant platinum-free catalyststoward alkaline hydrogen oxidation reaction (HOR) represents a significantendeavor to enable commercialization of alkaline fuel cells. This, however,remains a grand challenge. Herein, a robust defective-carbon-supported Rucatalyst (denoted as Ru@C) is crafted to achieve efficient and CO-tolerantHOR in alkaline media via delicately tailoring interfacial chemistry of catalyst.Notably, the degree of defects in the carbon support is the key to tune theinterface chemistry. An integrated experimental and density functional theorycalculations study demonstrates that the favorable interfacial chemicalinteraction between Ru and carbon support controlled by the covalentlybonded Ru─O─C redistributes the d electrons of Ru and downshiftsits d-bandcenter, which in turn weakens the hydrogen adsorption and suppresses theRu 4d→CO 2 * back donation. Consequently, the optimized Ru@C catalystrenders a 6.6-fold enhancement in mass activity (@25 mV) for alkaline HORover the conventional Ru/C counterpart, which also outperforms thestate-of-the-art catalysts. Intriguingly, the catalyst can tolerate 20 000 ppmCO, far exceeding that of commercial Pt/C and PtRu/C catalysts. This workelucidates the correlation between precisely tailored interfacial chemistry andHOR performance, and is expected to further enlighten the design ofadvanced catalysts.