Construction of Sulfur-Doped and Cyanide-Modified Carbon Nitride Photocatalysts with High Photocatalytic Hydrogen Production and Organic Pollutant Degradation

Element doping and functional group modification engineering serve as efficient approaches that contribute to the improvement of the functional efficiency in graphitic carbon nitride (CN) materials. A CN photocatalyst co-modified with sulfur (S) and cyano moieties was prepared through thermal condensation polymerization. The introduced S species modulated the band structure, increased charge carrier mobility, and significantly promoted charge separation and transport. Additionally, the introduction of cyano groups extended light absorption range and improved the material’s selective adsorption of reactant molecules. The as-prepared sulfur-modified CN photocatalyst obtained after a 6 h thermal treatment, which was capable of degrading organic pollutants and producing hydrogen (H2) efficiently and stably, exhibited excellent catalytic performance. The photocatalyst’s photocatalyst exhibited a significantly enhanced photocatalytic activity, with a Rhodamine B (RhB) removal efficiency reaching 97.3%. Meanwhile, the H2 production level reached 1221.47 μmol h−1g−1. Based on four-cycle experiments, the photocatalyst exhibited excellent recyclability and stability in both H2 production processes and photocatalytic organic pollutant degradation. In addition, mechanistic studies confirmed the dominant role of ·OH and ·O2− as active species responsible for the reaction system’s performance. This study highlights that the co-decoration of heteroatoms and functional groups can markedly enhance the photocatalytic performance of CN-based materials, offering considerable potential for future applications in energy conversion and environmental remediation.