Abstract: Photocatalytic hydrogen production technology offers a means of converting solar energy into chemical energy contained in hydrogen for human consumption. However, traditional photocatalysts restrict the progress of photocatalytic technology owing to the straightforward complexation of carriers and lack of active sites. Thus, in this work, the number of active sites and carrier separation efficiency have been significantly improved by non-metallic modification and modulation of the geometry of carbon nitride. It has been demonstrated that oxygen doping enhances the energy band structure of benzene-substituted O-doped g-CN nanotubes (BOCN). Oxygen, in conjunction with the benzene ring, creates redox energy level positions that are spatially separated. One-dimensional tubular structures synthesised by supramolecular self-assembly have a thin-walled structure capable of exposing more active sites. Additionally, the adsorption equilibrium of H⁺ on the catalyst is further enhanced. The in-depth analysis of each component through experiments and theoretical calculations contributes to a reasonable photocatalytic mechanism for decomposing aquatic hydrogen.

Key words: Carbon nitride, Photocatalysis, Hydrogen evolution, Charge separation