C/g-C3N4 hybrid nanosheets obtained by gaseous stripping to boost photocatalytic hydrogen evolution performance

Graphitic carbon nitride (g-C3N4) is a new generation metal-free polymer semiconductor photocatalyst for solar water splitting. In this work, we report a gaseous treatment in wet nitrogen ambience, which can realize carbon deposition and nanosheets stripping in one step. The free carbon functions as electron trapping and the bridge of g-C3N4 and co-catalyst Pt, producing a high charge separation efficiency. The carbon content in the C/g-C3N4 hybrid nanosheets can be adjusted by changing ethanol content in the treating ambience. The optimized C/g-C3N4 (5%) nanosheets achieve the highest hydrogen evolution rate of 10482.62 μmol h−1 g−1, which is 2.3 times that of g-C3N4 (0%) nanosheets, even 13.9 times that of bulk g-C3N4. Optical properties, charges transfer and specific surface area of the C/g-C3N4 hybrid nanosheets are measured to discuss the mechanism of photocatalytic hydrogen evolution. The combination of high optical absorption in visible region and high charge separation efficiency contribute to the enhanced hydrogen evolution performance.