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

Abstract

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·CoO_x cocatalyst. The synthesized CoOOH·CoO_x/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·CoO_x 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.