Surface phase of TiO2 modified with La2O3 and its effect on the photocatalytic H2 evolution

Abstract TiO 2 nanoparticles modified with La 2 O 3 were prepared by an impregnation method using anatase TiO 2 support (La 2 O 3 /TiO 2 ) or amorphous Ti(OH) 4 support (La 2 O 3 /Ti(OH) 4 ). The bulk and surface crystalline phases of La 2 O 3 /TiO 2 (or La 2 O 3 /Ti(OH) 4 ) have been characterized by X-ray powder diffraction (XRD) and UV Raman spectroscopy. Besides, morphology and particle size of La 2 O 3 /TiO 2 and La 2 O 3 /Ti(OH) 4 samples have been determined by TEM (transmission electron microscope) and Brunauer–Emmett–Teller (BET), respectively. It is found that the phase transformation and increase of the particle size of TiO 2 can be more effectively inhibited in the La 2 O 3 /TiO 2 than in the La 2 O 3 /Ti(OH) 4 . Photocatalytic experiments indicated that the La 2 O 3 /TiO 2 (or La 2 O 3 /Ti(OH) 4 ) samples with surface anatase phase have the similar overall photocatalytic activities. Moreover, it is found that the high crystallinity of surface anatase phase is benefit for the high photocatalytic activity of TiO 2 modified with La 2 O 3 .