The use of poly(vinyl phosphonic acid) microgels for the preparation of inherently magnetic Co metal catalyst particles in hydrogen production

• Published in: Journal of power sources 2014, Vol.246, p.55-62
• Main Authors: SAHINER, Nurettin, SAGBAS, Selin
• Format: Article
• Language: English
• Subjects: Alternative fuels. Production and utilization; Applied sciences; Catalysts; Electrical engineering. Electrical power engineering; Energy; Exact sciences and technology; Fuels; Hydrogels; Hydrogen; Hydrogen production; Materials; Metal ions; Microgels; Nickel; Particulate composites; Phosphonic acids
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.07.043

Novel poly(vinyl phosphonic acid) (p(VPA)) micro particle and composite p(VPA)-silica micro particle hydrogels are synthesized using a micro-emulsion polymerization technique. Porous p(VPA) particles are generated after removal of silica particles upon treatment of composite p(VPA) with 0.5 M NaOH solution. Bare, composite with silica, and porous p(VPA) micro particle hydrogels are used as templates and as reactors. Metal nanoparticles, Co, Ni, and Cu are generated in situ inside these hydrogels by chemical reduction of the absorbed metal ions with a reducing agent such as sodium boron hydride (NaBH sub(4)), and are used as catalyst in hydrogen production by hydrolysis of NaBH sub(4) in a basic medium and ammonia borane (AB). The effects of reloaded metal ions, the reaction temperature, the porosity, the reusability, and the type of metal (Co, Ni, Cu) are investigated. The activation energy for hydrolysis of NaBH sub(4), and AB by p(VPA)-Co is 28.02 and 25.51 kJ mol super(-1), respectively. The mass susceptibility measurements of composite p(VPA)-Co microgel is found as ferromagnetic. It is found that p(VPA) microgels provided better catalytic performance in comparison to macro p(VPA) hydrogels due to improved properties such as higher surface area, pore structure, and inherently magnetic behavior after multiple loadings-reduction of Co(II) from aqueous medium.