Engineering graphitic carbon nitride with expanded interlayer distance for boosting photocatalytic hydrogen evolution

Regulating interlayer distance is a crucial factor in the development of two-dimensional (2D) nanomaterials. A 2D metal-free photocatalyst, such as graphitic carbon nitride (g-C3N4), exhibits morphology- and microstructure-dependent photocatalytic activity. Herein, we report a straightforward and facile route for the preparation of unique lamellar g-C3N4, by co-firing melamine and ammonium chloride via microwave-assisted heating. Through the decomposition of NH4Cl, the evaporation of NH3 gas can effectively overcome van der Waals forces, expanding the interlayer distance of g-C3N4, thereby creating a lamellar structure consisting of nanosheets. Compared with bulk g-C3N4, the NH3-derived lamellar g-C3N4 exhibits a larger specific surface area and enhanced optical absorption capability, which increase photocatalytic hydrogen production because of the highly active structure, excellent utilization efficiency of photon energy, and low recombination efficiency of photogenerated charge carriers. This study provides a simple strategy for the regulation of the g-C3N4 microstructure toward highly efficient photocatalytic applications.