Surveying the Synthesis, Optical Properties and Photocatalytic Activity of Cu 3 N Nanomaterials.

This review addresses the most recent advances in the synthesis approaches, fundamental properties and photocatalytic activity of Cu 3 N nanostructures. Herein, the effect of synthesis conditions, such as solvent, temperature, time and precursor on the precipitation of Cu 3 N and the formation of secondary phases of Cu and Cu 2 O are surveyed, with emphasis on shape and size control. Furthermore, Cu 3 N 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 Cu 3 N is therefore of interest. In fact, the density of states in the d-band of Cu has an influence on the band gap of Cu 3 N. Moreover, the potential of Cu 3 N 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 Cu 3 N. Nevertheless, combining them with other potent photocatalysts, such as TiO 2 and MoS 2, augments the efficiency to 99%. Finally, the review concludes with perspectives and future research opportunities for Cu 3 N-based nanostructures.