H2 Generation From Nabh4 Methanolysis Via Magnetic Field Sensitive Ionic Liquid Coated Silica Particles as Catalyst

Abstract

Upon the preparation of magnetic (Fe3O4) nanoparticles (NPs), they were coated with amino-functionalized silica (SiO2@NH2) via the modified Stber method. Siv coated Fe3O4 (Fe3O4@SiO2) particles and SiO2@NH2 coated Fe3O4 (Fe3O4@SiO2@NH2) particles were turned into ionic liquid (IL) colloids as Fe3O4@SiO2@NH3+Cl-, Fe3O4@SiO2@NH3+NO3- and Fe3O4@SiO2@NH3+HSO4- by the treatment of Fe3O4@SiO2@NH2 with hydrochloric acid (HCl), nitric acid (HNO3) and sulfuric acid (H2SO4), respectively. The size of the prepared silica-based particles was approximately 500 nm by SEM images, and the zeta potential values varying between -59 and +26 mV. The catalytic activity performances of these silica-based particles as catalysts were investigated for H-2 generation from methanolysis of NaBH4 in terms of the types of particles, reusability, recyclability, the concentration of NaBH4, and the reaction temperature. Amongst the prepared IL colloids, Fe3O4@SiO2@NH3+Cl- particles were found to be the most effective catalysts for the methanolysis reaction of NaBH4. The maximum Hydrogen Generation Rate (HGR) value of 13188 +/- 196 mL H-2 g(-1) min(-1) was attained at 500mM NaBH4 by using 50 mg Fe3O4@SiO2@NH3+Cl- as catalyst at 25 degrees C. Additionally, turn over frequency (TOF) value was calculated as 43.1 +/- 3.1 H-2 mol (mol of N.min)(-1) for Fe3O4@SiO2@NH3+Cl- under the same reaction conditions. Moreover, activation energy (Ea) values for the methanolysis of NaBH4 using Fe3O4@SiO2@NH3+Cl- particles as catalyst were found as 32.5 +/- 0.5, 39.9 +/- 0.3 and 24.4 +/- 0.7 kJ mol(-1) in the temperature range of -15-45, -30-0 and 15-45 degrees C, respectively, that are comparable and even better than for most of the metal nanoparticle catalysts used in NaBH4 methanolysis reactions.