Kinetic Analysis of the Reduction of 4-Nitrophenol Catalyzed by CeO2 Nanorods-Supported CuNi Nanoparticles

CuxNi100-x (x = 0, 20, 40, 60, 80, and 100) nanoparticles were uniformly grown on the surface of CeO2 by the liquid impregnation method. The as-prepared nanocomposite abbreviated CuxNi100-x-CeO2 was characterized by various techniques including, X-ray powder diffraction, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, Brunauer-Em-mett Teller surface area analyzer, and transmission electron microscopy. The catalytic activity of CuNi100-x CeO2 nanocomposites was investigated in 4-nitrophenol (4-NP) reduction reaction. Among the synthesized nanocomposites, Cu60Ni40 CeO2 exhibited the best catalytic activity (rate constant as 0.1654 s(-1)) with high recyclability for five consecutive runs. The mechanism of the reduction was studied, and the adsorption equilibrium constant of 4-NP (K4-Nn) and borohydride (KBH4-) was calculated by using the Longmuir Hinshelwood model. The energy of activation (E-a) and thermodynamic parameters such as activation enthalpy (Delta H-double dagger), entropy (Delta S-double dagger), and Gibbs free energy (Delta G(double dagger)) have also been determined.