Fuel Processing Technology, Vol.128, 394-401, 2014
Modified macroporous P(2-hydroxyethyl methacrylate) P(HEMA) cryogel composites for H-2 production from hydrolysis of NaBH4
Macroporous p(2-hydroxyethyl methacrirlate) p(HEMA) cryogel was synthesized at 18 degrees C via cryopolymerization technique and chemically modified with a quaternization agent (QA), 3-chloro-2hydroxypropyl trimethyl ammonium chloride in basic medium to produce Q-p(HEMA). Then superporous p(HEMA) cryogel was used as template for in situ Co and Ni metal nanoparticle preparation and used as soft reactors in H-2 generation reactions from hydrolysis of NaBH4. To increase the catalyst contents of the cryogel composites, multiple metal ion loading and reduction steps were carried out for faster H-2, generation from the hydrolysis reaction. The effects of several parameters, such as number of reloading-reduction cycles (1st, 2nd and 3rd), metal nanoparticle types, concentration of NaBH4, alkalinity of reaction medium, and temperature on the H-2 generation reactions were investigated. It was found that the 3rd time Co(II) loaded-reduced Q-p(HEMA)-Co cryogel composite is highly active as the turn over frequency (TOF) and the hydrogen generation rate (HGR) values were 62.9 +/- 1.8 (mot H-2) (mol catalyst minri and 26,641.0 +/- 3.6 (ml H-2) (min)(-1) (g of M)(-1) at 70 degrees C which is even better than the fastest known catalyst, ruthenium. (C) 2014 Elsevier B.V. All rights reserved.