Zn2SnxTi1–xO4 Continuous Solid-Solution Photocatalyst for Efficient Photocatalytic CO2 Conversion into Solar Fuels

Abstract

Solid-solution materials exhibit promising photocatalytic performance for complete photocatalytic conversion of carbon dioxide (CO2) and water (H2O) into solar fuels and oxygen (O2). In this study, Zn2SnxTi1–xO4 (0 ≤ x ≤ 1) solid-solution photocatalysts with an inverse spinel structure were prepared using the molten-salt-assisted method. The Zn2SnxTi1–xO4 solid-solution photocatalyst effectively enhanced CO2 photoreduction due to the increase in optical excitation centers, including SnO4 tetrahedrons, ZnO6, and TiO6 octahedrons. Numerous photoexcited centers generated sufficient photogenerated carriers to increase the overall redox reaction rate of H2O and CO2. In situ Fourier transform infrared spectroscopy analysis revealed that the distortion of the structural unit of the Zn2SnxTi1–xO4 solid solution not only improved the separation of photogenerated charges but also promoted the activation of CO2 molecules on the catalyst surface. Moreover, the reduction in the effective mass of photogenerated carriers in the Zn2SnxTi1–xO4 solid solution enables their fast migration, which results in excellent carrier movement. This synergistic effect leads to enhanced photoactivity of Zn2SnxTi1–xO4 for CO2 reduction.