ZnO/g-C3N4 S scheme photocatalytic material with visible light response and enhanced photocatalytic performance

ZnO/g-C3N4 composite photocatalyst is prepared by ultrasonic dispersion method for Rhodamine B (RhB) degradation from wastewater. The characterization results of the ZnO/g-C3N4 indicate that ZnO nanoparticles are uniformly dispersed on the surface of two-dimensional g-C3N4 nanosheet. In addition, the existence of heterojunction between ZnO and g-C3N4 promotes the effective separation of photogenerated carriers and improves the photocatalytic activity of the ZnO/g-C3N4. The influence of ZnO/g-C3N4 dosage on the RhB photocatalytic degradation removal is investigated. The RhB photocatalytic degradation removal is 95.6 % and reaction rate constant is 0.0201 min-1 at addition amount of 4.0 g/L. The RhB photocatalytic degradation kinetics process is fitted by Langmuir-Hinshelwood equation. Compared with the difference between the peak positions of N1s, C1s, O1s and Zn2p in ordinary and in situ XPS spectra, the analysis result indicates that the transfer path of photoelectrons is from ZnO to the g-C3N4 under visible light irradiation. The RhB photocatalytic degradation mechanism conforms to the S-scheme mechanism combined with DFT calculation. ZnO/g-C3N4 still has good photocatalytic degradation activity after 5 cycles.