In situ synthesis of 2D ultrathin cobalt doped g-C3N4 nanosheets enhances photocatalytic performance by accelerating charge transfer

A series of cobalt-doped g-C3N4 nanosheet photocatalysts with different cobalt doping content are prepared using melamine and cobalt nitrate as precursor. The prepared samples are carefully characterized and the results demonstrate that the thickness of cobalt-doped g-C3N4 is about 8～10 nm, with a large specific surface area, narrow band gap energy, and abundant Co–N active sites. The thinner g-C3N4 nanosheet structure shortens the distance of carriers migrating to the surface, and reduces the chance of carrier recombination. The Co–N bonds served as the separation centers to promote charge transfer for enhancing photocatalytic performance. The 1 wt% cobalt-doped g-C3N4 nanosheet sample achieved excellent photocatalytic activity and stability, which H2 evolution and MB degradation are 3.2 and 1.67 times higher than the bulk g-C3N4. This work provides an effective way to construct a new high activity g–C3N4–based photocatalytic material for the decomposition of aquatic hydrogen and wastewater treatment.