Morphology regulation and photocatalytic performance of modified g-C₃N₄

Graphitic carbon nitride (g-C₃N₄) has been widely studied and applied in the field of catalysis, but its photocatalytic performance still needs to be improved. In this work, g-C₃N₄ was protonated with hydrochloric acid and nitric acid, and the products were denoted as HCN and NCN, respectively. The photocatalytic performances of g-C₃N₄, HCN, and NCN were compared by the degradation of Rhodamine B solution (RhB) under visible light. The structure, morphology, optical, and electrochemical properties of the samples were systematically characterized. It was found that both HCN and NCN were composed of uniform nanosheets, and HCN had a better separation. The UV–Vis and PL spectra showed that the band gap of the material was widened, and the photogenerated electron-hole pairs can be effectively separated. From the photocatalytic degradation test, HCN and NCN showed stronger photocatalytic activity than g-C₃N₄, and the degradation efficiency was HCN > NCN > g-C₃N₄, the degradation of RhB were 98%, 95%, and 78% respectively at 75 min. The experiment of the free radical scrubber showed that superoxide free radical was the main active substance of photocatalytic degradation. Our results have potential application value for the design of two-dimensional photocatalytic materials.