Dynamic Ti3+ and In3+ dual active sites on In2TiO5 to enhance visible-light-driven gas-phase photocatalytic CO2 reduction

Abstract

Amorphous materials offer novel and cooperative active sites that challenge the limits of heterogeneous crystalline catalysts. This work represents an initial development of a feasible amorphous photocatalyst for CO2 photoreduction. We optimise the bandgap and crystal structure of amorphous In2TiO5 to facilitate the conversion of CO2 to CH4. The XAFS analysis identifies Ti3+ as the active site. The reaction between H2O and In3+ produces protons that lower the oxidation state of In3+ to In2+. Moreover, adding 2D nanolayers of MoSe2 to In2TiO5 increases CH4 production from 4.14 to 6.15 µmol/g. We report the effect of multiphoton flux and find that it leads to a 1.28-fold increase in CH4 production. The combined in situ DRIFTS and DFT analyses elucidate underlying chemical pathways in photocatalytic CO2 reduction. © 2023 Elsevier B.V.