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

Competitive H 2 oxidation severely limits CO 2 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 H 2 activation remains challenging. Here, we report a junction-confined FeO-Pt/SiO 2 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 O 2 activation at the interface. Consequently, CO oxidation proceeds via a dominant low-barrier interfacial pathway (0.20 eV), while weakened H 2 adsorption at the FeO–Pt junction mitigates competitive H 2 oxidation under H 2 -rich conditions. The catalyst achieves >70% CO 2 selectivity at complete CO conversion over 80–160 ° C and maintains stability for 100 h without noticeable deactivation under H 2 -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.