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

Abstract

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.

Highly Dispersed K- and Pd-Comodified Fe Catalyst for CO2 Hydrogenation to Higher Alcohols

“…It is worth noting that when the reduction temperature is raised to 350 °C, the CO adsorption signals almost disappear over 0.3K-1Pd/Fe 2 O 3 and 1Pd/Fe 2 O 3 catalysts. The alloying effect can downshift the Pd d-band center for mitigating electron backdonation of the Pd d-orbital to the CO π*-orbital, which consequently weakens the CO adsorption. − The above results confirm the formation of the PdFe alloy in a reducing atmosphere.…”

CO-Tolerant Hydrogen Oxidation Electrocatalysts for Low-Temperature Hydrogen Fuel Cells

“…(g) Relationship diagram between Pt 5 d -band centers of different model catalysts and corresponding CO adsorption energy. Reprinted with permission from ref . Copyright 2023, American Chemical Society.…”

“…When solely applied, the regulation of those strategies to the PGM electronic structure and d -band center is limiting, and the CO adsorption is usually still much stronger than H 2 . In view of this, our group for the first time proposed a cascade electron back-donation mitigating strategy by combining alloying and SMSI effects to synergistically boost the CO-tolerance of Pt-based catalysts (Figure e) . The Fe–N–C supported PtNiMo alloy NPs (PtNiMo/Fe–N–C) showed considerable CO-tolerance in 1000 ppm CO/H 2 .…”

V–O Species-Doped Carbon Frameworks Loaded with Ru Nanoparticles as Highly Efficient and CO-Tolerant Catalysts for Alkaline Hydrogen Oxidation

“…Moreover, introducing oxyphilic atoms into graphene can also enhance Ru–support interactions, facilitating electron transfer between Ru and the substrate and further regulating the Ru electronic structure . This might alleviate CO adsorption on Ru and enhance the CO tolerance of the catalysts . In addition, the finely constructed oxyphilic sites on the carbon framework can adsorb a large amount of OH – , creating a locally negatively charged region around Ru, preventing OH – in the electrolyte solution from occupying the hydrogen adsorption sites on Ru, facilitating the HOR process and improving the stability of Ru. , …”