{001}/{101} facets co-exposed TiO_2 microsheet arrays with Lanthanum doping for enhancing photocatalytic CO_2 reduction

摘要

{001}/{101} facets co-exposed TiO_2 microsheet arrays with Lanthanum doping were prepared by a one-step hydrothermal method. The crystal structure, morphology, photoelectrochemical properties and photocatalytic CO_2 reduction performance of La-doped TiO_2 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 La_2O_3 particles loaded on TiO_2 MSAs with high La dopant. Combining various characterizations and tests, it indicates that the dopant of La enhances photocatalytic activity of TiO_2 MSAs by increasing optical absorption, transportation of photoinduced electrons, and effective absorption of CO_2. The photocatalytic CO_2 reduction main product was CO on La-doped TiO_2 MSAs, and CO yield of TiO_2 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 TiO_2 MSAs. Furthermore, the mechanism of La doping for enhanced photocatalytic CO_2 reduction of TiO_2 MSAs is proposed.