Kinetics of p-Nitrophenol Reduction Catalyzed by PVP Stabilized Copper Nanoparticles

Copper nanoparticles (CuNPs) in aqueous medium were prepared with alkaline hydrazine hydrate as the reductant and PVP as the stabilizing agent without any inert gas protection. Careful variation in the amount of reductant resulted in formation of two stable CuNPs dispersions with different average sizes and consequently different localized surface plasmon resonance absorbances. These two as-synthesized CuNPs dispersions were used to catalyze the model p-nitrophenol reduction reaction. The kinetics of reduction was monitored as a function of concentration and temperature of reactants. Using this we determined the activation energy, pre-exponential factor and the entropy of activation for the two types of CuNPs samples. Catalytic activities of the CuNPs were found to be affected mainly by their activation energies.