A simple melamine-assisted exfoliation of polymeric graphitic carbon nitrides for highly efficient hydrogen production from water under visible light

Polymeric graphitic carbon nitride with a two-dimensional (2D) structure has intensive potential applications in hydrogen production from water splitting under visible light irradiation. Searching for an efficient technology is the key to synthesizing 2D materials from bulk powders. Here, a simple, highly-efficient, large-scale and low-cost melamine-assisted exfoliation route is reported to obtain quasi-2D carbon nitride using an oil bath. Quasi 2D carbon nitride possesses a high specific surface area (116.76 m 2 g −1 ), a larger bandgap (by 0.13 eV), an enhanced electronic transport ability in the in-plane direction, a prolonged photo-excited charge carrier lifetime, and a lowered recombination of photo-induced electrons and holes resulting from the quantum confinement effect. These make enormous contributions to the photoactivity for hydrogen production under visible light. Therefore, the melamine-assisted liquid exfoliation route can be applied to large-scale polymeric carbon nitride photocatalyst production and is envisaged to have great promise for the exfoliation of other materials with layered structures. Compared to the bulk-CN, the quasi-2D-CN possesses a unique electronic structure, enlarged bandgap, prolonged lifetime, increased surface area and enhanced electronic transport, and exhibits highly efficient hydrogen production from water under visible light.