Enhanced Photocatalytic Hydrogen Peroxide Synthesis Performance of Polymeric Carbon Nitrides with a Controllable Carbonization Strategy

Polymeric carbon nitrides have gained significant interest in photocatalysis owing to their tunable electronic and structural diversity. However, traditional polymeric carbon nitrides, regardless of their structural motifs, have shown limited or no effectiveness in producing H₂O₂ through photocatalysis. This study introduces a controllable carbonization technique assisted by post molten salt treatment, as demonstrated across three structurally distinct polymeric carbon nitrides: melon and two ionic variants. Through the molten salt treatment, the photoactivities for H₂O₂ synthesis were significantly enhanced on all three carbon nitride variants. The enhanced activity is attributed to the precise control of the carbonization process, resulting in the formation of a composite material comprising carbon and carbon nitride. The formation of this composite material not only improves charge separation but also imparts hydrophobic properties to the material, thereby preventing the decomposition of H₂O₂ synthesized under photocatalytic conditions.