Synergistically Mitigating Electron Back-Donation by Single-Atomic Fe–N–C and Alloying to Boost CO-Tolerance of Pt in Hydrogen Oxidation

Developing CO-tolerant Pt-based catalysts for the hydrogen oxidation reaction (HOR) is critical for the commercialization of fuel cells and thus receiving increasing interest. Although it is known that weakening the CO adsorption on Pt can improve CO tolerance, efficient strategies are still needed. Inspired by theoretical simulations, we propose here a cascade strategy to synergistically mitigate electron back-donation of Pt 5d → CO 2π* by introducing single-atomic Fe–N–C substrate and alloying, which significantly boosts the CO-tolerance of Pt-based HOR catalysts. The obtained PtNiMo/Fe–N–C can maintain above 80% HOR current density after 2000 s in 1000 ppm CO/H2, substantially outperforming control catalysts and ranking among the state-of-the-art catalysts. The in situ surface-enhanced infrared adsorption spectroscopy validates that the effectively weakened CO adsorption contributes to improved CO tolerance. This strategy opens up opportunities for designing advanced HOR catalysts with desired CO tolerance.