Boosting O2 activation and substrate adsorption over single-atom Zr-doped Pt/CeO2 for enhanced glucose oxidation to glucaric acid.

CeO2 is widely employed in heterogeneous catalysis due to its excellent oxygen storage and release capacity. However, enhancing oxygen adsorption and activation as well as substrate adsorption capability in aqueous-phase to optimize catalytic oxidation performance remains a significant challenge. Herein, a Pt/Zr-CeO2 catalyst was prepared via a single-atom doping strategy. Characterization revealed that Zr atoms were successfully incorporated into the CeO2 lattice, markedly increasing the oxygen vacancy concentration and enhancing the surface Lewis acidity. This dual modulation not only creates abundant sites for molecular oxygen activation but also facilitates efficient adsorption of aldehyde and hydroxyl groups of glucose. Mechanistic studies indicate that the enhanced oxygen vacancies promote the generation of superoxide radicals (O2-). These radicals are further converted into peroxide species (O22-) under aqueous conditions and induce the formation of hydroxyl radicals (OH), which synergistically activate CH and OH bonds of glucose. The synergy between oxygen vacancies and Lewis acid sites enables the highly selective production of glucaric acid under mild conditions. Meanwhile, the catalyst exhibits excellent stability during cycling tests, with no obvious deactivation. This study demonstrates that single-atom Zr doping is an effective strategy for modulating the defect chemistry and surface acidity of CeO2-based catalysts, providing new insights into the design of high-performance oxidation catalysts for biomass valorization.