Rational design of BixFeyVO4/g-C3N4 heterojunction for photocatalytic reduction of Cr(VI)

Abstract

High visible light utilization and rapid charge separation are of great importance for environmental photocatalysis. Single photocatalyst always suffers from high recombination of photogenerated electron-hole pairs and low redox ability. Elemental doping and heterojunction construction are effective approaches to improve the photocatalytic performance. Herein, we designed and synthesized a novel BixFeyVO4/g-C3N4 (BFC) binary heterojunction via facile coprecipitation followed by calcination processes. The doping of Fe endows BiVO4 with narrower bandgap, which boosts its light response and redox ability. The construction of heterojunction facilitates charge separation that makes BFC heterojunction displaying much higher photocatalytic activity than those of single semiconductors. The highest Cr(VI) photoreduction rate (k) of BFC binary heterojunction is 78 (45) times of BiVO4 (FeVO4). Additionally, the binary heterojunction can still maintain high photoreduction efficiency (98%) of Cr(VI) even after five cycling tests showing excellent photocatalytic stability. This research provides novel idea for synergistic application of doping and heterojunction in environmental photocatalysis.