Photocatalytic degradation of imidacloprid by composite catalysts H3PW12O40/La-N-TiO2 under visible light.

Catalysts H3PW12O40/La-N-TiO2 were prepared and characterized by FT-IR, N2 adsorption-desorption analysis, SEM and UV-Vis diffuse reflection spectrum (DRS). It was demonstrated that Keggin structure of H3PW12O40 retained in composite materials by the FT-IR test; After doping La-N, the BET surface area of them is nearly 2 times as that of pure TiO2; the SEM images of the catalysts revealed that they were consist of relatively uniform spherical grains with good dispersion; UV-Vis DRS showed the photoresponse performance of the prepared composites for the visible light area were improved after doping La and N. The prepared composites were used as photocatalysts in degradation of pesticide imidacloprid. Results revealed that 30%H3 PW12O40/0.3%La-1.0%N-TiO2 possessed the best photocatalytic activity under visible light above 400 nm. Thus, imidacloprid were degraded 91.57% after 3 h irradiation. When 30% H3PW12O40/0.3%La-1.0%N-TiO2 was used as catalysts, degradation ration could even reach 98.89% after 6 h.