Controllable Synthesis And Performance Of Visible-light-responsive BiVO₄ Photocatalysts

Photocatalytic oxidation technology has good activity and wide application prospects in the degradation of organic pollutants such as tetracycline hydrochloride（TH）.BiVO₄is a kind of better semiconductor photocatalysts with visible light response.In this paper,BiVO₄photocatalysts with excellent morphology and visible light photocatalytic performance were prepared controllably by improving the synthetic method.The main contents are as followed:BiVO₄ nanophotocatalysts were prepared by solvothermal method and high-temperature calcination with bacitracin as a biological template.The synthesized BiVO₄nanomaterials were tested and characterized.In the process of biomimetic synthesis,bacitracin induced the formation of spherical particles by controlling the growth and aggregation of BiVO₄grains.The process of template calcination caused a certain amount of C doping.The effects of calcination temperature,the amount of bacitracin and the amount of Bi（NO₃）₃and NH₄VO₃on the photocatalytic activity of BiVO₄were investigated.Under the optimal reaction conditions,the prepared BiVO₄had excellent photocatalytic activity under visible light,and the degradation efficiency of TH reached 98.2%within 1 h.This was mainly because the spherical BiVO₄photocatalysts had large specific surface area and narrow band gap,which accelerated the separation of photo-generated carriers to a certain extent.The growth mechanism of spherical BiVO₄photocatalysts synthesized with bacitracin as a template and the mechanism of photocatalytic degradation of TH under visible light were speculated.Porous olive-like BiVO₄ photocatalysts were prepared by solvothermal method using glycerol and water as solvents,and the obtained photocatalysts were characterized and analyzed.During the solvothermal process,glycerol had a certain induction effect on the growth and aggregation of BiVO₄grains,and BiVO₄nanoparticles with porous olive-like morphology were synthesized.Under the optimal reaction conditions,the degradation rate of TH within 1 h was 91.1%under visible light.This was mainly due to its large specific surface area,narrow band gap and abundant surface oxygen defects,which made it easier to separate photo-generated electrons and holes.A heterojunction between the BiVO₄materials and g-C₃N₄materials was constructed.The BiVO₄/g-C₃N₄heterojunction accelerated electron conduction,thus enhanced photocatalytic performance.99.0%of TH can be degraded within 1 h under visible light.The growth mechanism of porous olive-like BiVO₄photocatalysts prepared by using glycerol and water as solvents and the mechanism of photocatalytic degradation of TH under visible light were proposed.