Taguchi-optimized walnut shell catalysts for enhanced hydrogen generation in methanol/propylene glycol solvents

Abstract

In this study, catalysts were synthesized from walnut shell (WS), for hydrogen production from sodium borohydride (NaBH4). Taguchi method was used to determine the most efficient of these catalysts to save time, material and labour. Subsequently, methanolysis reactions were carried out using the catalyst with the highest activity to achieve the highest hydrogen production under various experimental conditions. Additionally, the effect on H2 generation rate (HGR) was thoroughly evaluated by using methanol + propylene glycol mixture as solvent in hydrogen generation reactions. As a result of the studies, the highest HGR obtained in methanol medium using WS-catalyst was determined as 7198.2 mLmin- 1g- 1 at 60 degrees C. Moreover, the activation energy (Ea) of this catalyst was determined to be 9.80 kJ/mol. In the reaction using methanol + propylene as solvent, the maximum HGR was 132300 mLmin- 1g- 1 at 60 degrees C and the Ea was 45.54 kJ/mol. SEM-EDX, XRD and XPS analyses were used for the characterization of the WS-catalyst.