Rapid and robust hydrogen generation from sodium borohydride in optimum mixture of methanol and ethylene glycol using phosphorus-doped chitosan polymer matrix dispersed on alumina nanoparticles

Abstract

Here, the highly efficient hydrogen (H-2) generation by sodium borohydride (NaBH4) in a novel synergistic mixture of methanol and ethylene glycol using phosphorus-doped chitosan polymer matrix incorporated on alumina particles was investigated. The efficiency of P-doped chitosan-alumina hybride catalyst for H-2 generation from NaBH4(NaBH4-HGR) in methanol, ethylene glycol, and methanol + ethylene glycol mixture showed significant differences. In particular, there is a very effective performance for NaBH4-HGR in a methanol + ethylene glycol mixture. The HGR values by mixture of methanol, ethylene glycol and methanol/ethylene glycol were 2342, 7364 and 13548 ml min(-1)g(-1), respectively. Moreover, the H-2 generation rate (HGR) value by NaBH4 using P-doped chitosan-alumina with the combination of methanol (8 ml) + ethylene glycol (2 ml) was 25,964 ml min(-1)g(-1). Also, activation energy (Ea) was 30.62 kJmol(-1). Additionally, the mechanism of H-2 release by NaBH4 solvolysis reactions in the methanol + ethylene glycol mixture using P-doped chitosan-alumina was evaluated. In the methanol + ethylene glycol mixture, both the low viscosity of methanol and the high acidity of ethylene glycol are likely to have a positive synergistic effect on H-2 production at the same time. Moreover, both the positivity of the P atoms and the increased acidity of the alumina become attractive to the negatively charged ions present in the reaction medium.