N-doped graphitic carbon-incorporated g-C3N4 for remarkably enhanced photocatalytic H2 evolution under visible light

Abstract

Described herein is a facile one-pot strategy to synthesize N-doped graphitic carbon-incorporated g-C3N4 by adding slight amount of citric acid into urea as the precursor during thermal polymerization. The obtained materials retained the original framework of g-C3N4 and show remarkably enhanced visible light harvesting and promoted photo-excited charge carrier separation and transfer. The high-resolution N 1s spectrum of XPS showed a graphitic N peak, which could be attributed to N-doped graphitic carbon. In addition to the common-recognized light harvesting enhancement and charge carrier recombination inhibition, the incorporation of N-doped graphitic carbon into the planar framework of g-C3N4 is suggested to result in extended and delocalized π-conjugated system of this copolymer, thus greatly elevating the photocatalytic performance for H2 evolution by water splitting under visible light. The H2 evolution rate on N-doped graphitic carbon-incorporated g-C3N4 reached 64 μmol h−1, which is almost 4.3 times the rate on pure g-C3N4. This approach may provide a promising route for rational design of high performance, cost-effective and metal-free photocatalysts.