Promotion of intramolecular electron transfer in g-C3N4 tubes by introducing pyridine structure to accelerate photocatalytic hydrogen evolution

The design of highly efficient photocatalysts for water splitting is critical to the production of hydrogen energy. Reducing carrier recombination and increasing intramolecular charge transfer are considered to be the keys to improving the performance of photocatalysts. In this work, a tubular polymer network containing a carbon-rich π-electron conjugated system (defined as VPPX-CN) was constructed by supramolecular self-assembly using pyridine-containing nicotinamide and melamine as precursors. Through various characterization methods and mechanism analysis, the performance and structure of the synthesized samples were thoroughly investigated. It is found that the intramolecular charge is effectively separated, and the special tubular structure has a large specific surface area, which reduces the rebinding of carriers. The average hydrogen production rate of the optimal sample VPP0.3-CN was 2316.2 μmol g-1 h-1, which was 4 times higher that of PCN. After 5 times of recycling within 25 h, the photocatalytic performance of the photocatalyst remained stable. This study provides a solution to the problems of high carrier recombination rate and low charge transfer rate in photocatalytic performance.