Ultra-thin carbon nitride nanosheets for efficient photocatalytic hydrogen evolution

In this paper, a simple and green method has been developed to fabricate ultra-thin graphite carbon nitride (g-C3N4) nanosheets by repolymerizing clean fluffy precursors with abundant hydrophilic groups. These hydrophilic groups are prone to produce endogenous gases for the exfoliation of g-C3N4. As expected, the obtained ultra-thin g-C3N4 nanosheets (UCN-200 as a representative sample) possess a large specific surface area (128.5 m2 g−1), a huge pore volume (0.35 cm3 g−1), and ultra-thin nanosheet structure (∼6 nm), which provide a wealth of reaction sites for photocatalytic hydrogen evolution. In addition, the ultra-thin structure not only improves the catalytic reduction potential by negatively shifting the conduction band edge, but also shortens the migration distance of photogenerated carriers, resulting in the efficient charge separation and hydrogen evolution reaction. Thus, UCN-200 exhibits excellent and stable photocatalytic hydrogen evolution performance (1254.75 μmol g-1h−1), which is 21.9 times higher than that of pristine g-C3N4.