Exfoliated and plicated g-C3N4 nanosheets for efficient photocatalytic organic degradation and hydrogen evolution

Exfoliated and plicated g-C₃N₄ nanosheets (CNsF) were prepared through a thermal-chemical exfoliation in which the bulk g-C₃N₄ was obtained first under thermal exfoliation, and then was exposed to an acidic etching using hydrofluoric acid under hydrothermal condition. The acidic etching not only exfoliated g-C₃N₄ nanosheets by disrupting weak van der Waals forces between layers, which led to formation of a monolayer or a few layers of g-C₃N₄ nanosheets, but also made disordered defects on its surface and created plicated g-C₃N₄ nanosheets. Under visible-light illumination, the optimized sample (CNsF-6%) showed a hydrogen evolution rate of 54.13 μmol h^?1g^?1 (without co-catalyst) and a specific surface area of 121.4 m² g^?1, which were about 4.7 and 2.5 times, respectively, higher than pristine g-C₃N₄. It also showed remarkably enhanced photocatalytic performance in removing various organic pollutants. This remarkable improvement probably arises from the porous nanosheets and an increased number of active sites resulting from the CNsF, which subsequently enhanced the charge separation efficiency. This work provided an alternative way to obtain highly active g-C₃N₄ photocatalysts.