Self-assembly of tungstophosphoric acid/acidified carbon nitride hybrids with enhanced visible-light-driven photocatalytic activity for the degradation of imidacloprid and acetamiprid

In this paper, a novel efficient hybrid photocatalyst consisting of tungstophosphoric acid (HPW) and acidified carbon nitride (ACN) was successfully prepared. HPW and ACN interact through hydrogen bonding interactions to improve the photocatalytic activity of the HPW/ACN composite by means of enhanced photogenerated hole-electron separation efficiency. Graphitic carbon nitride was treated with a mixture of concentrated nitric acid and sulfuric acid to obtain porous ACN. The composite photocatalyst was then prepared by self-assembly of acidified carbon nitride and HPW under acidic conditions. The characterization results of HPW/ACN indicated the successful introduction of HPW and the effective interaction between HPW and ACN. Based on photocatalytic degradation experiments, it was concluded that HPW could act as the photogenerated electron trapping agent, providing adsorption sites as well as photocatalytic redox reaction sites. Moreover, the HPW/ACN showed excellent performance in the degradation of imidacloprid and acetamiprid under visible light irradiation (lambda > 400 nm). The results of photocatalytic degradation revealed that the degradation rate constant of HPW/ACN (0.0058 min(-1)) was 16 times higher than that of ACN (3.55 x 10(-4) min(-1)) in the photocatalytic degradation of imidacloprid and that the photocatalytic degradation rate constant of HPW/ACN (0.0017 min(-1)) was 30 times higher than that of ACN (5.64 x 10(-5) min(-1)) in degrading acetamiprid.