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 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 MoS_2, augments the efficiency to 99%. Finally, the review concludes with perspectives and future research opportunities for Cu₃N-based nanostructures. [ABSTRACT FROM AUTHOR]