In situ generated Cu nanoparticles catalyze the reduction of 4-nitrophenol to 4-aminophenol in the presence of NaBH 4 very efficiently at room temperature with good recyclability up to four cycles. The precursor compound, formed by hydrothermal treatment of copper chloride with urea at 120 1C for 6 h, produces Cu nanoparticles on reduction with NaBH 4 during the course of the reaction. The synthesized precursor and the catalyst are characterized by various analytical techniques such as XRD, FTIR, TGA, SEM-EDX, TEM, and UV-visible spectroscopy.

The sheet-like CuO shows enhanced catalytic activity, compared to polycrystalline CuO for the catalytic degradation of methylene blue and methyl orange.

Porous CuO nanostructure exhibits high catalytic activity for the degradation of methylene blue and methyl orange in the presence of H2O2.

This account provides an overview of current research activities on nanoparticles containing the earth-abundant and inexpensive element copper (Cu) and Cu-based nanoparticles, especially in the field of environmental catalysis. The different synthetic strategies with possible modification of the chemical/ physical properties of these nanoparticles using such strategies and/or conditions to improve catalytic activity are presented. The design and development of support and/or bimetallic systems (e. g., alloys, intermetallic, etc.) are also included. Herein, we report synthetic approaches of Cu and Cu-based nanoparticles (monometallic copper, bimetallic copper and copper (II) oxide nanoparticles/nanostructures) and impregnation of such nanoparticles onto support material (e. g., Co O nanostructure), along with their applications as environmental catalyst for various oxidation and reduction reactions. Finally, this account provides necessary advances and perspectives of Cu-based nanoparticles in the environmental catalysis.

Addition of Ni significantly enhances the reaction rates of Cu/Co3O4 for the catalytic reduction of nitroaromatic compounds.