Enhanced Catalytic Activity in the Reduction of 4-Nitrophenol and 2-Nitrophenol by p(AMPS)-Cu(0) Hydrogel Composite Materials

Cu(0) metal nanoparticles were prepared inside p(2-acrylamido-2-methyl-1-propansulfonic acid) hydrogel networks. The p(2- acrylamido-2-methyl-1-propansulfonic acid)-Cu composites were used in the reduction of 4-nitrophenol and 2-nitrophenol, as model reactions in the presence of excess NaBH4, and showed excellent catalytic activity. The reduction rate of 4-nitrophenol with p(2- acrylamido-2-methyl-1-propansulfonic acid)-Cu composites, even in the presence of a very low amount of catalyst (1.1 mg Cu(0)) at close to room temperature (30 °C), resulted in a very high value (0.1032 min-1) in comparison to Co(0) and Ni(0) catalysts prepared under very similar conditions. The kinetic parameters were determined at different reaction temperatures and the activation energies for 4- nitrophenol and 2-nitrophenol were found to be 28.2 and 39.2 kJmol-1, respectively. Keywords: Hydrogel reactor, hydrogel-Cu catalyst, 4-nitrophenol reduction, swollen catalyst systems, hydrogel networks, activation energies, Catalytic Activity