Synthesis and properties of Ag/ZnO/g-C3N4 ternary micro/nano composites by microwave-assisted method

Ag/ZnO/g-C3N4 ternary micro/nanocomposites, as novel visible-light-driven photocatalysts, were prepared by a simple and convenient microwave-assisted method. The resulting ternary structure micro/nano composites were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, ultraviolet-visible diffuse reflectance spectroscopy and infrared radiation techniques to examine its phase structure, valence state, morphological, thermal and optical properties. Well crystallized Ag/ZnO/g-C3N4 ternary micro/nano composites were synthesized under microwave-radiation for 15 min with the output of 240 W. Further experiments indicated Ag-(5.0mol%)/ZnO/g-C3N4 photocatalyst in degradation of methylene blue exhibited an outstanding photocatalytic activity and its reaction rate constant (k, 0.0084 min(-1)) is 7.5, 2.4 2.9 and 3.5 times higher than that of monolithic ZnO (k, 0.0011 min(-1)), ZnO/g-C3N4 (k, 0.0035 min(-1)), Ag-(5 mol%)/ZnO(k, 0.0029 min(-1)) and Ag-(5mol%)/g-C3N4 (k, 0.0024 min(-1)) respectively. Finally, a possible photocatalytic mechanism of Ag/ZnO/g-C3N4 photocatalyst in degradation process was proposed. This work provides a feasible strategy to synthesize an efficient ZnO-based photocatalyst which combines structure and properties of different dimensional components and made this ternary system an exciting candidate for sunlight-driven photocatalytic water treatment.