Enhanced visible-light driven photocatalytic activity of hybrid ZnO/g-C3N4 by high performance ball milling

The ZnO/g-C 3 N 4 photocatalyst was prepared by ball milling and demonstrated enhanced photocatalytic degradation of RhB under visible light irradiation. The photocatalyst is consisted of ZnO and g-C 3 N 4 heterojunctions formed by the shear stress during the mechanical treatment. The addition of g-C 3 N 4 can improve the photocatalytic performance of ZnO under visible light. The heterojunction formed between ZnO and g-C 3 N 4 decreased the recombination rate of photogenerated carriers and improved the photocatalytic activity of the ZnO/g-C 3 N 4 hybrids. The optimal ZnO/g-C 3 N 4 photocatalyst with 10   wt% g-C 3 N 4 showed a degradation efficiency of 51.3% for RhB under visible light, which is 2.1 times higher than that of pristine ZnO. The electron paramagnetic resonance (EPR) measurement showed that the OH radicals are the dominant active species in photocatalytic process under both full solar spectrum and visible light irradiation. And the OH radical generation is much more efficient under full solar spectrum than that under visible light due to the UV response of ZnO. This work provides a simple method for the design and preparation of novel heterojunction photocatalysts.