Ti/ZnO–Fe2O3 composite: Synthesis, characterization and application as a highly efficient photoelectrocatalyst for methanol from CO2 reduction

In this paper, Ti/ZnO–Fe2O3 composite derived from Ti/Schiff base intercalated ZnFe layered double hydroxides was used as thin film electrode in CO2 photoelectroreduction. The influence of molar ratio of Ti/Fe and calcination temperature, which would affect the composites' physicochemical property and the photoelectrocatalytic performance for CO2 reduction, were investigated in detail. The characterization results from XRD, SEM, TEM, UV-vis and BET showed that Ti/ZnO–Fe2O3 composite with flower–like crystal from had small particle sizes, narrow band gap and excellent textural properties. The final product of CO2 photoelectroreduction was methanol and the intermediates were formic acid and formaldehyde. The methanol field reached at 0.773 mmol/cm2 after 3 h reaction with 0.5 V voltage by Ti/ZnO–Fe2O3 composite with Ti/Fe = 1, calcined at 800 °C. In addition, the CO2 photoelectroreduction pathway and the reason for highly efficient photoelectrocatalytic activity of the composite were also discussed.