Strontium-induced phase, energy band and microstructure regulation in Ba 1− x Sr x TiO 3 photocatalysts for boosting visible-light photocatalytic activity

A polyacrylamide gel method has been developed for fabrication of Ba 1− x Sr x TiO 3 (BST, x = 0.1–0.5) photocatalysts. When x = 0.1–0.2, the BST photocatalyst is in a tetragonal phase, and when x is other value, the BST photocatalyst is in a cubic phase. The microstructure of BST photocatalysts changes from an irregular polyhedron in the tetragonal phase to cuboid in the cubic phase. The change of the phase structure makes the color parameter b * value of BST photocatalysts change from negative to positive, and the E g value and photocatalytic activity increase with the increase of the x value. The optimum catalyst content, drug concentration, pH value and illumination time for the degradation of tetracycline hydrochloride (TC-HCl) by BST photocatalysts were 1 g L −1 , 20 mg L −1 , 6.77 and 120 min, respectively. The degradation pathway of TC-HCl and the toxicity of the intermediate products were also analyzed. This technique of phase structure, microstructure, energy band engineering and photocatalytic activity regulation is helpful for the development of other similar photocatalysts.