The use of superporous p(AAc (acrylic acid)) cryogels as support for Co and Ni nanoparticle preparation and as reactor in H-2 production from sodium borohydride hydrolysis


ŞAHİNER N. , Seven F.

ENERGY, cilt.71, ss.170-179, 2014 (SCI İndekslerine Giren Dergi) identifier identifier

Özet

Here, we report for the first time the use of p(AAc (p(acrylic acid)) cryogel for in situ metal nanoparticle preparation, and their use as a superporous reactor for H-2 generation from hydrolysis of NaBH4. Superporous p(AAc) cryogels and conventional hydrogels were prepared via free radical polymerization technique at low (-18 degrees C) and moderate (40 degrees C) temperatures, respectively. They were characterized by employing various methods such as swelling experiments, optical imaging, and SEM (Scanning Electron Microscopy) analysis. By reducing Co2+ and Ni2+ ions within p(AAc) cryogel and hydrogel matrices, the obtained Co and Ni metal nanoparticles were employed for H-2 generation from NaBH4 hydrolysis. Various factors such as porosity, metal type, temperature, and the amount of sodium hydroxide were investigated to determine their effects on hydrogen generation from NaBH4 hydrolysis. Activation energy (Ea), enthalpy (Delta Eta(#)) and entropy (Delta S-#) for NaBH4 hydrolysis by superporous p(AAc)-Co metal composites were 2935 kJ mol(-1),=36.85 kJ mol(-1), and 157.88 J mol(-1)K(-1), respectively. Cryogels showed better catalytic activity than conventional hydrogels in the hydrolysis reaction, and have a higher TOF (turnover frequency) value of 4.10 mol H-2 (mol catalyst min)(-1) compared to conventional hydrogels, due to its highly porous nature, short diffusion distances and fast response times. (C) 2014 Elsevier Ltd. All rights reserved.