INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, vol.39, no.28, pp.15455-15463, 2014 (SCI-Expanded)
Highly porous p(2-hydroxyethyl methacrylate) p(HEMA) cryogels were synthesized via cryopolymerization technique and used as template for Co, Ni, and Cu nanoparticle preparation, then as composite catalyst systems in H-2 generation from hydrolysis of both NaBH4 and NH3BH3. Due to their highly porous and open microstructures, p(HEMA)-Co cryogel composites showed very effective performances in H-2 production from hydrolysis of both chemical hydrides. The characterization of p(HEMA) cryogels, and their metal composites was determined via various techniques including swelling experiments, digital camera images, SEM and TEM images, AAS and TGA measurements. The effect of various parameters on the hydrolysis reaction of NaBH4 such as metal types, concentration of chemical hydrides, amounts of catalyst, alkalinity of reaction medium and temperature were investigated in detail. It was found that Co nanoparticles are highly active catalysts in H-2 generation reactions from both hydrides. The hydrogen generation rate (HGR) of p(HEMA)-Co was 1596 (mL H-2) (min)(-1) (g of Co)(-1) which is quite good in comparison to reported values in the literature. Furthermore, kinetic parameters of p(HEMA)-Co metal composites such as energy, enthalpy and entropy were determined as Ea = 37.01 kJmol(-1), Delta H# = 34.26 kJmol(-1), Delta S# = -176,43 Jmol(-1) K-1, respectively. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.