Photocatalytic reduction of CO2 on Cu2O-loaded Zn-Cr layered double hydroxides

A series of Cu2O-loaded Zn-Cr layered double hydroxides (LDHs) was prepared via an in situ reduction process from Cu-Zn-Cr ternary LDHs and applied to the photoreduction of CO2. The formation of Cu2O nanoparticles and the preservation of the LDH structure was confirmed by X-ray diffraction and transmission electron microscopy. Among the loaded LDHs, the 0.1Cu(2)O@Zn1.8Cr LDH exhibited optimal activity for the conversion of CO2 into CO in pure water and was superior to both the corresponding Cu-Zn-Cr ternary LDH and pristine Zn2Cr LDHs. In addition, the production of CO was further promoted by increasing the solubility of CO2 using a nano-bubble solution instead of pure water. The loaded Cu2O nanoparticles probably function as effective electron traps, promoting charge separation and providing active sites for CO2 reduction.