The effect of the solvent medium on hydrogen production from sodium borohydride using a bio-derived catalyst from Prosopis farcta

Abstract

In this study, hydrogen production from sodium borohydride (NaBH4) was investigated using a bio-based catalyst derived from Prosopis farcta fruit in various solvent systems. The catalyst was synthesized via carbonization in a nitrogen atmosphere following chemical activation with KOH, ZnCl2, and CH3COOH. BET, SEM-EDS, and XRD analyses indicated notable changes in the textural and structural properties of the biomass-derived carbon after treatment, including an increase in surface area and the development of a porous carbon structure. Catalytic activity was evaluated via the methanolysis of NaBH4; here, the catalyst activated with 30% KOH at 400 degrees C for 45 min exhibited the highest performance. Among the solvent systems, the methanol-propylene glycol (1:1) mixture provided the highest hydrogen production rate (11.325 mL H2 gcat(-1) min(-1)). The reaction followed first-order kinetics with an activation energy of 26.775 kJ/mol. Reusability tests indicated that the catalyst remained active after repeated cycles, although a gradual decrease in activity was observed. These findings demonstrate the potential of Prosopis farcta-derived carbon as a sustainable catalyst material for hydrogen production from NaBH4.