Engineering Holey Defects on 2D Graphitic Carbon Nitride Nanosheets by Solvolysis in Organic Solvents

In this work, we present the in situ exfoliation of graphitic carbon nitride (g-C3N4), engineering holey defects on 2D g-C3N4 layers, and formation of self-assembled graphene via solvothermal treatment of g-C3N4-bulk in various organic solvents. Methyl alcohol, isopropyl alcohol, tetrahydrofuran, and dimethylformamide were chosen for exfoliating and modifying g-C3N4 sheets based on their compatibility with g-C3N4 in Hansen parameters. Uniform holey defects on 2D g-C3N4 nanosheets were successfully engineered using tetrahydrofuran solvent in a facile solvothermal process. The introduction of N vacancies in heptazine units and the formation of the holey structure of tetrahydrofuran-modified g-C3N4 sample (C3N4-THF) led to high photocatalytic performance due to enhanced mass transfer, shortening of the charge diffusion lengths, and increased charge separation during the photocatalysis process. Furthermore, full exfoliation of the engineered nanostructure of holey defect C3N4-THF into a monolayer in reaction media led to maximizing accessible reducing and oxidizing active sites. As a result, the C3N4-THF sample achieved photocatalytic activity with a H2 evolution rate at stationary point as high as 31256.9 μmol h–1 g–1 under 1 Sun illumination of a solar simulator.