Sulfur Doped Carbon-Rich g-C 3 N 4 for Enhanced Photocatalytic H 2 Evolution: Morphology and Crystallinity Effect

Molecular design for the intercalation of S and C in the framework of g-C3N4 is a promising strategy to increase visible light harvesting and facilitate the separation of photoinduced electron/hole pairs. Herein, we reported a facial method to prepare porous S doped g-C3N4 nanotubes by thermal polymerization of urea and 2-thiobarbituric acid. The obtained catalysts contain certain carbon and sulfur atoms in the aromatic rings substituting the nitrogen atoms in g-C3N4, which narrows down the band gap, and increases the separation of photoinduced charge carriers. Meanwhile, nanotube formation increases the specific surface area of catalyst. The synergistic effect of S doped carbon rich g-C3N4 and nanostructure forming results in superior photocatalytic H2 evolution from water splitting. The study shows that the photocatalytic H2 evolution is correlated with the crystallinity of S doped g-C3N4. Schematic illustration for framework of 0.3S-CN and its photocatalytic hydrogen evolution mechanism.