Abstract
Poly(1-vinyl imidazole) (p(VI)) hydrogel network were used as template for metal nano- particle/cluster preparation such as Cu, Co and Ni. Moreover, these hydrogel-M (M:Cu, Co, and Ni) composites were also employed as reactor e.g., in generation of hydrogen from the hydrolysis of various boron compounds (NaBH4 and NH3BH3), and in reduction of nitro phenols such as 4-nitrophenol to 4-aminophenol. The p(VI)-M composite can further be made magnetic field responsive by in situ preparation of magnetic ferrites inside p(VI) for magnetic field responsive hydrogel-M composite catalyst systems. [Display omitted]
► P(VI) hydrogel network for metal ion absorption and reduction. ► In situ metal nanoparticle synthesis within hydrogel. ► Soft and flexible nanoreactors.
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.
