Cu and Co nanoparticle composites based on starch poly(acrylic acid) hydrogel: reusable catalysts for catalytic reduction of nitrophenol

摘要

Starch poly(acrylic acid) (St-p(AA)) hydrogel was synthesized by radical polymerization in solution of starch with acrylic acid as monomer, N,N'-methylenebisacrylamide as the cross-linking agent and potassium persulfate as the initiator. St-p(AA) was used as a reactor for in situ synthesis of copper and cobalt nanoparticles. St-p(AA)-Cu and St-p(AA)-Co nanocomposites were characterized by Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis and atomic absorption spectroscopy. Catalytic performances of the prepared starch-p(AA)-M (M: Cu, Co) hydrogel composites were investigated by using them as catalyst in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol. The effects of several parameters on the reduction reaction as temperature, catalyst amount and the initial concentration of NaBH4 were investigated. The activation energy, activation enthalpy and activation of entropy for the reaction were calculated as 36.32, 34.97 and -197.52 J mol(-1) K-1, respectively.