One-step construction of mesoporous cyano and sulfur co-modified carbon nitride for photocatalytic valorization of lignin to functionalized aromatics

Herein, mesoporous cyano and sulfur co-modified carbon nitride (MCSCN) is one-step constructed for the first time by a simple strategy using urea and trithiocyanuric acid as precursors. Trithiocyanuric acid can act as pore-fabricating units to form mesopores, meanwhile introduce cyano groups and sulfur atoms into carbon nitride. The constructed mesoporous structures effectively reduce the mass transfer resistance of macromolecular lignin in the photocatalytic reaction process. The synergistic effect of the modified cyano groups and sulfur atoms significantly improves the photocatalytic valorization effect of waste lignin to functionalized aromatics. As a representative of waste lignin, waste Camellia oleifera shell (WCOS) lignin can be efficently photocatalytic transformed to monophenolic compounds by MCSCN, and each gram of WCOS lignin can harvest 116.2 mg of functionalized aromatics, which is about 7 times higher than that by traditional g-C3N4 photocatalyst (16.7 mg/g).