Rational copolymerization strategy engineered C self-doped g-C3N4 for efficient and robust solar photocatalytic H2 evolution

Graphitic carbon nitride (g-C3N4) with unique physicochemical features has garnered much attention in artificial photosynthesis, yet the photoactivity of pristine g-C3N4 (PCN) is severely restricted because of its rapid charge recombination rate and narrow visible-light absorption. To this end, for the first time, here we reported a rational one-step copolymerization strategy for the fabrication of carbon self-doped g-C3N4 (CCN) by using melamine and chitosan as the starting materials. Experimental results indicated that the bridged N atoms were substituted by C atoms in the g-C3N4 matrix, resulting in the formation of delocalized big π bonds, thereby the obviously increased the electrical conductivity, remarkably extended the visible-light absorption region, and significantly improved the mobility of photoinduced electron-hole pairs. Consequently, the as-engineered CCN with abundant mesopores structure showed a dramatically boosting photocatalytic H2-evolved activity (1224 μmol g−1 h−1), 4.5-folds than PCN powders. Eventually, the resulting CCN exhibited an extremely long-term durable stability after storing in reaction solution for 90 days. Our work will bring about potential application in designing of high-performance g-C3N4 photocatalyst for renewable solar-to-H2 conversion.