Titanosilicates enhance carbon dioxide photocatalytic reduction

Abstract

In this study, we aimed to correlate the structural properties of mesoporous zeolites with their photo catalytic performance. We prepared three types of titanosilicate zeolite photocatalysts and characterized them in detail. Titanosilicate photocatalysts showed significantly higher selectivity to CO2 reduction products, i.e., CH4 and CO, than a commercial TiO2, P25. Among them, the photocatalysts TS-1-V and Lam-TS 1, which consist of unit-cell-thick nanosheets with MFI zeolite topology, had the highest photoreduction quantum efficiency. The TPD-CO2 results showed that Lam-TS-1 and TS-1-V samples have stronger interactions with both CO2 and H2O than TS-1-C. Furthermore, the amount of CO2 chemisorbed/ desorbed on Lam-TS-1 and TS-1-V was higher, indicating a higher number of interaction sites. Therefore, the key factors in photocatalytic CO2 reduction with titanosilicate catalysts are not only the strength and number of CO2 adsorption sites but also the hydrophilicity of the photocatalysts, which strongly affects their efficiency and selectivity.