In situ growth of a heterojunction cocatalyst on the g-C3N5 surface enhances charge transfer to improve photocatalytic activity

The photocatalytic activity of g-C3N5 is limited by its low photoelectric separation efficiency and high carrier recombination rate. To address this problem, the band gap of g-C3N5 was controlled via P doping, followed by deposition of a CoOOH·CoOx cocatalyst. The synthesized CoOOH·CoOx/P–C3N5 composite shows the characteristics of high photoelectric separation efficiency and low carrier recombination rate. DFT calculation and XPS revealed that P replaced the C atoms in g-C3N5 and interact with the Co atom to form an electron transport channel, showing P-dependent co-catalytic activity. The CoOOH·CoOx cocatalyst accelerated the electron transfer process of P–C3N5 while inhibiting the recombination of carriers and improving the photocatalytic reaction efficiency. The advantages of this strategy were verified by the degradation of TC, and the reaction rate of the obtained material was 59.6 times higher than that of pure g-C3N5. Using this strategy, the photoelectric separation efficiency was simultaneously enhanced, and then the fast recombination of the g-C3N5 carriers was effectively suppressed.