Utilization of Smart Hydrogel-Metal Composites as Catalysis Media

Various metal nanoparticles such as, Cu, Co, Ni, and Fe were prepared inside poly(1-vinyl imidazole) p(VI) hydrogel by the absorption of the corresponding metal ions from aqueous solutions and the reduction with suitable reducing agents such as NaBH4 and/or NaOH. TGA and ICP-AES were used to determine the metal particle content of p(VI)-M (M: Cu, Co, and Ni) composites. The prepared hydrogel-metal nanoparticle composites were proven to be resourceful as reaction container for the catalysis of various organic reactions. It was illustrated that p(VI)-M hydrogel-metal composites can be successfully used in the hydrolysis of NaBH4 for the generation hydrogen form NaBH4 and NH3BH3. Additionally, p(VI)-M composites were also illustrated in the catalysis of different organic reactions; e.g., these hydrogel-M are very effective in the reduction nitro aromatic compounds such 2-nitrophenol (2-NP) and 4-nitrophenol (4-NP) to their corresponding amine forms in the presence of aqueous NaBH4. Various parameters in the catalysis of hydrogen production and 4-NP reduction were determined. 2011 Elsevier Inc. All rights reserved.