Facile production of ultrathin graphitic carbon nitride nanoplatelets for efficient visible-light water splitting

Ultrathin graphitic carbon nitride nanoplatelets (UGCNPs) are synthesized by a facile manner via an efficient and eco-friendly ball milling approach. The obtained UGCNPs are 2–6 nm in size and 0.35–0.7 nm in thickness, with improved specific surface area over that of bulk graphitic carbon nitride. Photochemical experiments show that the UGCNPs are highly active in visible-light water splitting, with a hydrogen evolution rate of 1,365 μmol·h⁻¹·g⁻¹, which is 13.7-fold greater than that of their bulk counterparts. The notable improvement in the hydrogen evolution rate observed with UGCNPs under visible light is due to the synergistic effects derived from the increased specific surface area, reduced thickness, and a negative shift in the conduction band concomitant with the exfoliation of bulk graphitic carbon nitride into UGCNPs. In addition to metal-free visible-light-driven photocatalytic hydrogen production, the UGCNPs find attractive applications in biomedical imaging and optoelectronics because of their superior luminescence characteristics. [Figure not available: see fulltext.]