{001}/{101} facets co-exposed TiO2 microsheet arrays with Lanthanum doping for enhancing photocatalytic CO2 reduction

Abstract

{001}/{101} facets co-exposed TiO2 microsheet arrays with Lanthanum doping were prepared by a one-step hydrothermal method. The crystal structure, morphology, photoelectrochemical properties and photocatalytic CO2 reduction performance of La-doped TiO2 MSAs were investigated in detail. The results show that La mainly exists as Ti–O–La bonds through La atoms substituted the Ti atoms with low La dopant. The formation of Ti–O–La bonds also leads to the generation of oxygen vacancies for balancing the charge. However, the La exists as La2O3 particles loaded on TiO2 MSAs with high La dopant. Combining various characterizations and tests, it indicates that the dopant of La enhances photocatalytic activity of TiO2 MSAs by increasing optical absorption, transportation of photoinduced electrons, and effective absorption of CO2. The photocatalytic CO2 reduction main product was CO on La-doped TiO2 MSAs, and CO yield of TiO2 MSAs doped with 1.0% mol La reaches 102 μmol g−1 h−1, which is greatly improved compared to 83.72 μmol g−1 h−1 of pure TiO2 MSAs. Furthermore, the mechanism of La doping for enhanced photocatalytic CO2 reduction of TiO2 MSAs is proposed.