The role of oxygen vacancies on Pt/NaInO2 catalyst in improving formaldehyde oxidation at ambient condition

Abstract In order to gain an understanding of the role of oxygen vacancy in enhancing gaseous formaldehyde oxidation, mesoporous NaInO2 compounds were synthesized with different amount of oxygen vacancies while maintaining similar BET surface area. The NaInO2 compounds were designed as the support for platinum (Pt) nanoparticles loaded catalytic oxidation, exhibiting the best performance with a formaldehyde degradation ratio of 96.11%. Interfacial lattice mismatch was considered as the cause of oxygen vacancies and simulated by density functional theory (DFT). Special bridged bidentate species were observed in Pt/NaInO2 with oxygen vacancies during HCHO oxidation using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Based on our observations we propose, for the first time, that superoxide (O2 −) is the effective species that oxidizes formaldehyde, while oxygen vacancies provide pathways to transport O2 − from Pt nanoparticles to support surface thus offering more active sites for the reaction to take place.