Abstract
Poly(Acrylamide) (AAm) hydrogels were synthesized in bulk and reacted with NH2OH.HCl to develop a new functional group to confer high swelling, porosity and high metal ion binding abilities. The chemically-modified hydrogels, denoted as amidoximated poly(Acrylamide) (amid-p(AAm)) showed increased water swelling ability of up to 16-fold. The chemical modification induced structural changes were examined by FT-IR spectroscopy, water and pH swelling experiments, optical microscope images, titration studies, and even TG analysis. The amid-p(AAm) hydrogels were used as template for absorption of Co(II) and Ni(II) ions from their aqueous solutions and treated with aqueous NaBH4 for in situ metal nanoparticle preparation of the corresponding ions within the amid-p(AAm) matrices. The amid-p(AAm)-M (M:Co or Ni) composites were then used as catalyst in the hydrolysis of NaBH4 for H2 generation, and their catalytic performances were investigated. Various parameters for the hydrolysis of NaBH4 such as functionality of polymer matrices, the types of metal nanoparticles, metal catalyst amounts within hydrogel matrices, and temperature were investigated. Considerably low activation energy in comparison to similar studies in the literature were calculated for NaBH4 hydrolysis by amid-p(AAm)-Co metal composite systems: Ea = 17.26 ± 0.06.