This review addresses the most recent advances in the synthesis approaches, fundamental properties and photocatalytic activity of Cu3N nanostructures. Herein, the effect of synthesis conditions, such as solvent, temperature, time and precursor on the precipitation of Cu3N and the formation of secondary phases of Cu and Cu2O are surveyed, with emphasis on shape and size control. Furthermore, Cu3N nanostructures possess excellent optical properties, including a narrow bandgap in the range of 0.2 eV-2 eV for visible light absorption. In that regard, understanding the effect of the electronic structure on the bandgap and on the optical properties of Cu3N is therefore of interest. In fact, the density of states in the d-band of Cu has an influence on the band gap of Cu3N. Moreover, the potential of Cu3N nanomaterials for photocatalytic dye-degradation originates from the presence of active sites, i.e., Cu and N vacancies on the surface of the nanoparticles. Plasmonic nanoparticles tend to enhance the efficiency of photocatalytic dye degradation of Cu3N. Nevertheless, combining them with other potent photocatalysts, such as TiO2 and MoS2, augments the efficiency to 99%. Finally, the review concludes with perspectives and future research opportunities for Cu3N-based nanostructures.
Keywords: Cu3N; nanostructures; optical properties; photocatalysis; synthesis.