Facile one-step synthesis of hollow mesoporous g-C3N4 spheres with ultrathin nanosheets for photoredox water splitting

Abstract A facial, one-step soft templating method to synthesize the hollow mesoporous g-C3N4 spheres with high surface area and high porosity was developed, which taking advantage of both supramolecular assembly of cyanuric acid and melamine through hydrogen bonds and the structure-directing character of ionic liquid. The influence of solvent and ionic liquid content on the assemble behavior of the cyanuric acid-melamine complex is studied in detail, respectively. It is found that the as-prepared hollow g-C3N4 spheres possess plenty of mesopores with a high surface area, which is related to the release of volatile domains and decomposition of ionic liquids. Moreover, as-prepared g-C3N4 exhibit improved light absorption in visible ranges, faster separation rate of photogenerated hole-electron pairs than the bulk carbon nitride. Besides, the as-prepared hollow mesoporous carbon nitride exhibits almost 30 times higher than traditional g-C3N4 which calcined by melamine for the photocatalytic hydrogen evolution reaction under visible light irradiation, which may be caused by the fact that the high surface area is beneficial for improving light absorption in visible ranges, and finally enhancing the H2 evolution rate. This method paves new opportunities for designing other catalysts with high surface area.