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

Ag/ZnO/g-C 3 N 4 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-C 3 N 4 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-C 3 N 4 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-C 3 N 4 ( k , 0.0035 min −1 ), Ag (5 mol%) /ZnO( k , 0.0029 min −1 ) and Ag (5mol%) /g-C 3 N 4 ( k , 0.0024 min −1 ) respectively. Finally, a possible photocatalytic mechanism of Ag/ZnO/g-C 3 N 4 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.