Conjugated polyene-functionalized graphitic carbon nitride with enhanced photocatalytic water-splitting efficiency

Abstract Photoactivity of graphitic carbon nitride (g-C 3 N 4 ) is seriously restricted by high recombination rate of photoinduced charge carriers. Herein, a g-C 3 N 4 /conjugated polyene (CP) complex is synthesized for the first time via a simple low-temperature calcination process. Lower photoluminescence intensity, longer fluorescence lifetimes, and higher photocurrent density of this complex than those of pure g-C 3 N 4 indicate that CP works effectively as electron acceptors and quickly shuttles electrons through its high conductive network to decrease the recombination rate of photogenerated electrons and holes of g-C 3 N 4 and improve the photocatalytic hydrogen production rate from 810 to 1270  μ mol/g/h under visible light irradiation. The complex prepared by calcination at 340 °C exhibits better photoactivity than those at 240 and 400 °C. Hydrogen bonds between g-C 3 N 4 and CP not only help to transfer electrons, but also fix CP molecules firmly on the surfaces of g-C 3 N 4 . This complex shows an excellent physicochemical stability in the photocatalytic process as well. This work provides not only a novel cost-effective way towards the preparation of new efficient g C 3 N 4 based complexes with better photoactivity, but also a new modification route to other photocatalysts for enhanced photocatalytic hydrogen production.