Chitosan Grown Copper Doped Nickel Oxide Nanoparticles: An Excellent Catalyst for Reduction of Nitroarenes

Abstract

Chitosan (Ch) mediated room temperature synthesis of Cu doped NiO nanoparticles (ChCX1 to ChCX3) has been carried out by wet chemical method. X-ray powder diffraction (XRD) revealed that ChCX2 is a crystalline material with face-centered cubic (FCC) lattice while TEM image revealed semi cylindrical particles of ~ 12 nm size. The comparison of the FESEM images of ChCX2 and CX2 (synthesized in absence of Ch) clearly indicated that chitosan growth medium has led to the formation of smaller particles. The catalytic performance of ChCX2 was optimized in comparison to CX2 control where ChCX2 and CX2 catalyzed borohydride reductions of 4-NP were completed in 1.66 min and 18 min respectively. ChCX2 could be easily recycled for ten consecutive cycles and even in the 10th cycle; the reduction completed in 23 min. The reductions of 4-nitrobenzoic acid (4-NBA) and 4-nitroaniline (4-NA) were attempted under the optimized conditions for 4-NP reduction. ChCX2 catalyzed reductions of 4-NBA and 4-NA required 5 min and 4 min respectively while CX2 catalyzed identical reductions could complete in 14 and 13 min respectively. The catalyst exhibited high shelf life as it retained its full catalytic performance even after 8 month storage at room temperature.