Rapid microwave hydrothermal synthesis of ZnGa2O4 with high photocatalytic activity toward aromatic compounds in air and dyes in liquid water

ZnGa2O4 was synthesized from Ga(NO3)3 and ZnCl2 via a rapid and facile microwave-assisted hydrothermal method. The photocatalytic properties of the as-prepared ZnGa2O4 were evaluated by the degradation of pollutants in air and aqueous solution under ultraviolet (UV) light illumination. The results demonstrated that ZnGa2O4 had exhibited efficient photocatalytic activities higher than that of commercial P25 (Degussa Co.) in the degradation of benzene, toluene, and ethylbenzene, respectively. In the liquid phase degradation of dyes (methyl orange, Rhodamine B, and methylene blue), ZnGa2O4 has also exhibited remarkable activities higher than that of P25. After 32 min of UV light irradiation, the decomposition ratio of methyl orange (10 ppm, 150 mL) over ZnGa2O4 (0.06 g) was up to 99%. The TOC tests revealed that the mineralization ratio of MO (10 ppm, 150 mL) was 88.1% after 90 min of reaction. A possible mechanism of the photocatalysis over ZnGa2O4 was also proposed.