DyVO4/boron-doped g-C3N4 composite photocatalytic materials with enhanced visible-light purification properties

Novel DyVO4/boron-doped graphitic carbon nitride (DyVO4/g-C3N4B) composite photocatalytic materials were successfully fabricated by a facile heating method, and their crystal structure, morphology, light absorption properties were analyzed by various technologies. With the increases of DyVO4 content, the visible-light photocatalytic properties of DyVO4/g-C3N4B catalysts first increase and then decrease, and the 5.7% DyVO4/g-C3N4B catalyst with a proper DyVO4 content-shows the highest photocatalytic purification performance. Its NO conversion ratio is > 1.6 time higher than that of DyVO4, g-C3N4B and g-C3N4B. And its Cr(VI) reduction ratio is 2.6, 2.1 and 1.8 times higher than that of DyVO4, g-C3N4B and g-C3N4B, respectively. The obviously enhanced visible-light purification properties of 5.7% DyVO4/g-C3N4B are mainly ascribed to the fact that proper DyVO4 modified g-C3N4B promotes the efficient separation of photo-generated electron-hole pairs by the band alignment between g-C3N4B and DyVO4, as well as contributes to the narrowest band gap and the best photo-response in 420-700 nm region. Moreover, 5.7% DyVO4/g-C3N4B also shows enough catalytic stability as evidenced by the four recycling experiments. This work provides some useful insights to design and synthesize a series of novel and highly efficient g-C3N4-based composite photocatalytic materials for environmental purification applications.