Hydrogen-induced Ptσ+–O–Ti4+–(H–oxygen vacancy) interfacial sites in Pt/TiO2 for enhanced low-temperature CO oxidation

Understanding reconstructed interfacial sites is crucial for enhancing the catalytic conversion efficiency, as these sites can facilitate reactant adsorption, transformation, and desorption. Herein, we report an unconventional interfacial structure of Pt σ + –O–Ti 4+ –H δ + –oxygen vacancy (OV), in which atomic hydrogen binds to Ti 4+ sites via a charge-compensation mechanism involving subsurface OVs. This restructuring induced by hydrogen creates electron-rich Pt centers and interfacial oxygen, resulting in spatial elongation of the Pt–O and O–Ti bonds. This Pt σ + –O site, stabilized by –Ti 4+ –(H–OV), promotes the activation of CO adsorption/interfacially absorbed oxygen and interfacial lattice oxygen, effectively coupling the Langmuir-Hinshelwood and Mars-van Krevelen pathways. These sites facilitate the rapid CO 2 formation and desorption. Consequently, this system achieves complete CO conversion at 120 °C with an ultralow Pt loading of 0.17 wt% (even in the presence of 0.005% SO 2 and 10% vol H 2 O) and a 59-fold increase in turnover frequency compared to the control sample lacking this interfacial structure.