Highly active La2O3/Ti1−xBxO2 visible light photocatalysts prepared under supercritical conditions

La2O3/Ti1−xBxO2 nanocrystals are prepared under supercritical conditions in which the La2O3 is present in a separate phase adsorbed by TiO2 while B-dopants are incorporated into TiO2 lattice via TiOB bond. During degradation of methylene blue under visible irradiation, the as-prepared photocatalyst exhibits higher activity than the undoped TiO2, the La2O3/TiO2, the Ti1−xBxO2, and even the La2O3/Ti1−xBxO2 obtained via direct calcinations, showing synergetic promoting effects from the supercritical treatment, the La2O3 and the B-dopant. The B-doping extends light absorbance to visible region while the La2O3 could enhance the surface area and also capture the photoelectrons, leading to the lower recombination between photoelectrons and holes. Supercritical treatment results in well-crystallized anatase and high surface area, which facilitate the light absorbance, the adsorption of organic substrate, and the separation of photoelectrons from holes, leading to the enhanced quantum yield. Meanwhile, supercritical treatment may strengthen the interactions of the La2O3 and the B-dopants with TiO2, leading to enhanced promoting effects.