Metal-free pyridinium-based polymeric ionic liquids as catalyst for H2 generation from NaBH4

Monodispersed poly(2-vinyl pyridine) (p(2-VP)) polymeric particles were synthesized with a self emulsion polymerization (SEP) technique. Polymeric ionic liquid (PIL) particles such as poly(2-vinyl pyridine)-ethane (p(2-VP)C-++(2)), poly(2-vinyl pyridine)-butane (p(2-VP)C-++(4)), and poly(2-vinyl pyridine)-hexane (p(2-VP) C-++(6)) particles were then prepared from monodispersed p(2-VP) particles by modifying with 1,2-dibromobutane (DBE) 1,4-dibromobutane (DBB) and 1,6-dibromobutane (DBH), respectively. The hydrodynamic diameter of the prepared particles was found be in the range of 350 -400 nm, and the zeta potential of p(2-VP)C-++(n) (n: 2, 4 and 6) particles were found to be in the range of 26-28 my. The prepared PIL particles (p(2-VP)C-++(6) etc.) were shown to be very effective catalysts in H-2 generation by methanolysis of NaBH4. Various parameters, such as the effect of modifying agents on PIL particle, the amount of PIL particles, the amount of NaBH4 and temperature, affecting the H-2 production rate were investigated. Hydrogen generation rate (HGR) was calculated as 5433 +/- 141 mL H-2 g(-1) min(-1) for 50 mg p(2-VP)C-++(6) particles in the methanolysis of 500 mM NaBH4. The activation energy (Ea) of methanolysis of NaBH4 catalyzed by p(2-VP)C-++(6) particles was calculated as 20.84 +/- 0.76 kJ mol(-1), which is much lower than similar studies reported in the literature. (C) 2016 Elsevier Ltd. All rights reserved.