C4N quantum dots/g-C3N4 nanosheets organic homogeneous structure self-assembly for efficient charge separation and photocatalytic hydrogen evolution

Homogeneous structures play important roles in photogenerated charge separation in photocatalysis due to their structure similarity. Herein, C4N quantum dots/graphite-phase carbon nitride nanosheets assembly (C(4)NQDs/C(3)N(4)NSs) is achieved through a simple self-assembly process. Compared with original g-C3N4 nanosheets, C4N quantum dots have a narrower band gap of 1.83 eV, which is conducive to the effective utilization of visible light. The photocatalytic hydrogen production of the resultant C(4)NQDs/C(3)N(4)NSs assembly is up to 1980 & mu;mol g(-1) h(-1) and the apparent quantum yield (AQY) can reach 32% at 365 nm, which is two times higher than that of original g-C3N4 nanosheets. This can be ascribed to the strong electron absorption activity of pyrazine nitrogen in C4N quantum dots activating the conjugated structure of the whole complex skeleton and thus promoting the migration and separation of photogenerated charge carriers. More importantly, the obtained C(4)NQDs/C(3)N(4)NSs assembly shows high stability even after 6 recycles, indicating its potential for applications in the field of energy. This work provides an effective synthesis strategy for organic homogeneous structure assembly with high photocatalytic performance.