Ligand-induced reaction mechanism regulation on Sr/Nb2O5 for high-efficiency selective photocatalytic NO oxidation

Developing highly efficient photocatalysts that selectively convert NO pollutants to NO₃¯ while storing metabolic nitrogen for crops remains a great challenge. Simultaneously, there is a dearth of research investigating the relationship between the chemical environment and the activity of catalytic sites. Herein, an efficient impregnation approach to access atomically dispersed Sr single atoms supported on Nb₂O₅ is reported; meanwhile, various ligands (-Cl, -Br, -OH) are employed to customize the local structure. The results show that Cl-Sr/Nb₂O₅ exhibits excellent catalytic performance in eliminating NO, which is significantly superior to other catalysts. The introduction of Sr atom and ligand increases the energy barrier of NO₂ formation, thus improving the selectivity of converting NO to NO₃¯. This study highlights the importance of precisely designing the catalytic site at the atomic level, and the obtained insights may serve as a valuable guide for developing future catalyst designs.