Recent Advances in Photocatalytic Systems and Selectivity Control Mechanisms

Fossil fuel overuse intensifies energy and environmental crises, underscoring the urgency for renewable energy. Photocatalysis converts solar to chemical energy, showing promise in biomass valorization. As a key platform compound, glucose oxidation yields high-value products. This review systematically summarizes recent advances in photocatalytic glucose oxidation, with a focus on catalyst design and selectivity control mechanisms. Metal-based systems (e.g., TiO₂, ZnO, SnO₂) leverage crystallographic phase engineering, noble metal modification (Pt, Au), and defect engineering to enhance visible-light absorption and carrier separation. For instance, Pt/TiO₂ achieves 84.3% selectivity for glucaric acid via oxygen vacancy mediation, while Au/ZnO reduces the C2-C3 cleavage barrier to 0.45 eV, boosting lactic acid selectivity to 38%. Carbon nitride (g-C₃N₄)-based catalysts exhibit tunable bandgaps and high stability; oxygen-doped ultrathin g-C₃N₄ achieves 89.7% lactic acid yield via superoxide radical (O₂ ^-) pathways. Composite systems (e.g., Zn_xCd_1-xS) enable simultaneous H₂ evolution and lactic acid production (87% selectivity) through phase-boundary engineering. Key mechanisms include ligand-to-metal charge transfer, Schottky junctions, and single-atom catalysis, which regulate reactive oxygen species (·OH, O₂ ^-, ¹O₂) for site-specific oxidation. Challenges remain in scalability and energy efficiency, but integrated design strategies offer promising routes toward sustainable biomass refining.