Decoupling CO and H2 Oxidation Pathways via Junction-Confined FeO-Pt for Efficient Preferential CO Oxidation

Abstract Competitive H2 oxidation severely limits CO2 selectivity (typically <50%) during preferential CO oxidation (CO-PROX) on Pt catalysts. While metal–oxide interfaces can potentially circumvent this trade-off, constructing architectures that spatially decouple CO and H2 activation remains challenging. Here, we report a junction-confined FeO-Pt/SiO2 catalyst in which FeO species selectively decorate Pt nanoparticles, creating well-defined and closely contacted interfacial sites. Unlike randomly distributed FeO in conventional catalysts, this configuration enables electron redistribution from Pt to FeO, as revealed by Bader charge analysis. This electronic effect preserves strong CO adsorption on Pt (required for CO activation) while dramatically enhancing O2 activation at the interface. Consequently, CO oxidation proceeds via a dominant low-barrier interfacial pathway (0.20 eV), while weakened H2 adsorption at the FeO–Pt junction mitigates competitive H2 oxidation under H2-rich conditions. The catalyst achieves >70% CO2 selectivity at complete CO conversion over 80–160 °C and maintains stability for 100 h without noticeable deactivation under H2-rich conditions. This work demonstrates that precise spatial organization of metal–oxide interfaces can effectively decouple competitive reaction pathways, offering a generalizable strategy for designing selective oxidation catalysts beyond CO-PROX.