Exfoliation-induced O-doped g-C₃N₄ nanosheets with improved photoreactivity towards RhB degradation and H₂ evolution

Graphitic carbon nitride (g-C₃N₄) nanosheets exfoliated from their bulk-sized counterparts are limited by a quantum size effect-induced widened bandgap. In this work, an (NH₄)₂S₂O₈ (APS) induced thermal exfoliation approach is introduced to fabricate O-doped g-C₃N₄ nanosheets (OCNs). During this calcination process, the thermal decomposition products (NH₃ and H₂SO₄) from APS not only efficiently promote delamination, but also introduce O doping into the g-C₃N₄ structure, realizing the synchronization control of the electronic structure and morphology. Compared to the bulk g-C₃N₄, OCNs show exceptional enhancement of the photocatalytic degradation of RhB and H₂ evolution, owing to their enlarged specific surface area, more active edges exposed, and efficient photogenerated carrier separation.