Facile fabrication of tetragonal scheelite (t-s) BiVO4/g-C3N4 composites with enhanced photocatalytic performance

A novel ellipsoidal (t-s) BiVO4 modified g-C3N4 composite photocatalyst was fabricated via a facile two-step synthesis strategy in the assistance of ultrasonic and magnetic stirring method. In this typical process, (t-s) BiVO4 was prepared by using a modified polyol method, and the coupling process of (t-s) BiVO4 with g-C3N4 was executed after ultrasonic treatment in the ethanol system. The photocatalytic activity of the as-obtained composites was evaluated by monitoring the degradation process of Rhodamine B (RhB) under the simulated sunlight irradiation. The results revealed that the highest degradation efficiency can reach up to 97.7% in 120 min when the mass ratio of (t-s) BiVO4 and g-C3N4 came to be 1:16. And the optimum degradation rate was 0.03088 min(-1), which was 4.6 and 47.5 times faster than that of the bare g-C3N4 and (t-s) BiVO4, respectively. The trapping experiments were conducted to verify that h(+) and secondary-O-2-radicals were the main active species in the photocatalytic process. The enhanced photocatalytic performance can be attributed to the synergetic effect of the heterojunction formed at the interface of g-C3N4 and (t-s) BiVO4, which resulted in the enlarged optical absorption range and improved separation ability of photo-induced carriers.