Research Progress on Photocatalytic Reduction of CO2 by Modified Layered Double Hydroxides

The use of solar energy and semiconductor photocatalysts to reduce carbon dioxide (CO2) into high-value fuels and chemicals is a promising approach to alleviate the current energy crisis and climate change. Layered double hydroxides (LDHs) are a special two-dimensional anionic clay material with a brucite-like structure. They have excellent properties such as adjustable layer cation types, interlayer anion types, and layer ratio. LDHs have been widely used in catalytic fields such as carbon dioxide reduction, water splitting, and ammonia synthesis, and are considered safe and green new photocatalysts. In recent years, researchers have conducted in-depth studies on the photocatalytic CO2 reduction performance of hydrotalcite-like materials and have made certain progress. However, the low carrier mobility and low light utilization efficiency of pure LDHs greatly limit their catalytic reaction ability and further applications. More and more scientists are exploring methods based on regulating the structure of LDHs to improve the conversion efficiency and light utilization of products, such as changing the layer composition of LDHs, introducing vacancies in LDH structures, or coupling different types of semiconductors to construct heterojunctions. This article first summarizes the development history and structural properties of LDHs; Secondly, the mechanism of photocatalytic reduction of carbon dioxide was summarized; Thirdly, the application of LDH-based materials in photocatalytic reduction of CO2 was classified and summarized. Although LDH-based photocatalysts have made significant progress in the field of photocatalytic reduction of CO2, further exploration is still needed to investigate their photocatalytic active sites, mechanisms of action, synergistic mechanisms between components, and interfacial reaction mechanisms.