Carbon-Doped Porous Polymeric Carbon Nitride with Enhanced Visible Light Photocatalytic and Photoelectrochemical Performance

The photocatalytic activity of polymeric carbon nitride (CN) is strongly tied to its surface area, morphology, optical, and electronic properties. Herein, a straightforward approach to adjusting the electronic properties and morphology of CN materials by fine tuning their carbon content while preserving their high surface area is proposed. To do so, supramolecular assemblies based on CN monomers together with an additional carbon-rich monomer that does not participate in the preorganization are calcinated. The use of a supramolecular assembly as the precursor endows the CN material with a high specific surface area and an ordered morphology, whereas the addition of a carbon-rich monomer provides light carbon doping. As a result, the new CN exhibits excellent activity as a photoanode material in photoelectrochemical cells and as a photocatalyst for the hydrogen evolution reaction. Detailed studies reveal that the modified CN samples show enhanced charge carrier transfer and separation efficiency, improved light absorption response, a tunable energy band structure, a higher electrochemical surface area, and better electronic conductivity compared with a reference CN.