Non-Metal Polymeric Bioparticles Based on Maleic Acid/Citric Acid as a Catalyst for H2 Generation From Nabh4

Abstract

Novel metal-free catalysts were synthesized form maleic acid (MA) and citric acid (CA) based polymers for hydrogen generation form NaBH4. Surfactant-free-self-emulsion polymerization technique was used to synthesize poly(Maleic acid)(poly(MA)), poly(Citric acid)(poly(CA)) and poly(Maleic acid-co-Citric Acid) poly(MA-co-CA)) polymeric micro-particles in a single step. The prepared catalysts were characterized by zeta potential, SEM, FTIR and TGA. The hydrodynamic diameter of the poly(MA), poly(CA) and poly(MA-co-CA) micro-particles were found to be 0.681, 1.273, 1.604 mu m and the zeta potential of this micro-particles were found to be -6.90, -5.69 and -7.73 mV, respectively. Various parameters affecting the rate of H-2 production of polymeric catalysts, such as the amount of microparticles, the amount of NaBH4 and the ambient temperature were investigated. Hydrogen generation rate(HGR) was calculated as 84 +/- 44 ml H-2 g(-1) min(-1) for 50 mg poly(MA-co-CA)micro-particles in the hydrolysis of 50 mM NaBH4. The activation energy(E-a) of hydrolysis of NaBH4 catalyzed by poly(MA-co-CA)micro-particles was calculated as -1.66 +/- 0.76 kJ mol(-1), which is much lower than similar studies reported in the literature. The prepared poly(CA), poly(MA) and poly(MA-co-CA) micro-particles were shown to be very effective catalysts in H-2 generation by hydrolysis of NaBH4.