In situ hydrothermal etching fabrication of CaTiO3 on TiO2 nanosheets with heterojunction effects to enhance CO2 adsorption and photocatalytic reduction

Abstract

Solar-driven carbon dioxide (CO₂) reduction with water is an important and attractive approach for converting CO₂ to fuel and chemicals. Developing intimate heterostructure photocatalysts is essential for efficient solar energy conversion. Here, we fabricated an efficient CaTiO₃/TiO₂ heterostructure composite by simple in situ hydrothermal etching of {001} facet-exposed TiO₂ nanosheets with saturated calcium hydroxide solution. CaTiO₃/TiO₂ not only possesses an intimate contact heterostructure due to its matching band structures and similar crystal structures but also has enhanced-surface basicity to facilitate CO₂ adsorption and activation for the CO₂ conversion. Under irradiation, the CaTiO₃/TiO₂ sample greatly enhances photocatalytic CO₂ reduction and shows CO production (11.72 μmol g⁻¹ h⁻¹) 5.6 times higher than that of bare TiO₂ nanosheets. The excellent photocatalytic performance of the CaTiO₃/TiO₂ heterostructures is attributed to the intimate construction of CaTiO₃ on TiO₂ nanosheets to facilitate the separation of photogenerated charges and the basicity of CaTiO₃ to provide more abundant active sites for CO₂ adsorption. This study provides fundamental guidance for the rational design of efficient heterostructure photocatalysts for an outstanding photocatalytic CO₂ reduction performance.