Core/shell K0.5Na0.5NbO3/g-C3N4 sono-photocatalyst: Synthesis and catalytic activities in degradation of metronidazole

The sono-photocatalysis, as a type of low cost, highly efficient and environment friendly technology, has been attracted on account of its potential in water environment optimization. In this work, different contents of g-C3N4 incorporated K0.5Na0.5NbO3/g-C3N4 nanorods were synthesized for the sono-photocatalysis of metronidazole. The synthesized catalysts were subjected various measurements for investigating their phase, microstructure, physical and chemical performance, as well as catalytic activities in different processes. The incorporation of g-C3N4 on the surface of K0.5Na0.5NbO3 leads to the formation of heterojunction, which benefits to higher separation efficiency of photoinduced electron-hole pairs and thus results in higher catalytic activity. It is found that the K0.5Na0.5NbO3/15 %g-C3N4 shows the highest degradation efficiencies in sonocatalysis (similar to 64.4 %), photocatalysis (49.5 %) and sono-photocatalysis (similar to 99.2 %). In sono-photocatalysis, the synergistic sonochemical and photochemical effects result in the higher degradation efficiency. The reactive species of center dot OH, h(+), center dot O-2(-) and O-1(2) play key roles in degradation. The degradation mechanism and possible pathways were proposed on the basis of experimental results.