A g-C3N4@ppy-rGO 3D structure hydrogel for efficient photocatalysis

We propose a non-metallic g-C3N4 nanosheet with efficient photo-oxidation and reduction ability that is modified by two non-metallic materials graphene and polypyrrole. The composite was tested by water treatment, including hexavalent chromium and phenol. It offers a visible response, easy recovery, and high stability, with a higher photo-degradation rate than bulk g-C3N4. The photoelectric performance test showed that the composite has a reduced Eg (2.58 eV) that is 0.12 eV lower than g-C3N4 (2.70 eV). The rGH can transfer electrons, and ppy can transfer holes, which helps improve the separation rate of photogenerated charge of the g-C3N4. When ppy and rGH operate concurrently, the separation of the photogenerated charge is greatly improved. In addition, the results of Vb-XPS show that the value of the valence band top of the hybrid hydrogel is more negative than bulk g-C3N4. Therefore, the π-π conjugation of ppy and rGH can effectively improve the utilization rate of visible light, the photogenerated transfer rate, the photocatalysis-oxidation ability, and the change in valence band position of g-C3N4.