Design and Architecture of P-O Co-Doped Porous g-C3N4 by Supramolecular Self-Assembly for Enhanced Hydrogen Evolution

A novel phosphorus and oxygen co-doped graphitic carbon nitride (sheetP-O-CNSSA) photocatalyst was successfully synthesized and applied for H2evolution under visible light. In the synthesis process ofsheetP-O-CNSSA, the supramolecular complex was developed by the self-assembly and copolymerization reaction among melamine, cyanuric acid (CA) and trithiocyanuric acid (TCA) to act as g-C3N4precursors, while (NH4)2HPO4was applied as P and O precursors for element doping. The chemical structures, morphologies, and optical properties of thesheetP-O-CNSSAwere characterized by a series of measurements, i.e., XRD, FT-IR, SEM, TEM, UV-vis DRS, and PL. The results suggested that the introduction of P and O elements could enhance the separation and migration efficiency of photogenerated electrons and holes in the energy band of g-C3N4. The photocatalytic tests over Erythrosin B (EB) sensitizedsheetP-O-CNSSAindicated that the hydrogen evolution was greatly enhanced compared with other catalysts and non-sensitizedsheetP-O-CNSSAunder visible light irradiation. Finally, a possible dye-sensitized photocatalysis mechanism was also proposed on the basis of the as-obtained results.Keywords:P-O-co-doped g-C3N4;self-assembly;dye sensitization;hydrogen evolution