Hydrogen generation through water splitting reaction using waste aluminum in presence of gallium

Abstract

The in-situ hydrogen generation through water splitting reaction using waste aluminum wires has been studied in presence of room temperature liquid metal gallium and alkaline activator potassium hydroxide. Various proportions of gallium i.e. 50%, 75%, 90% and 95% (weight by weight of the total metal in reaction) were used in order to study the effect of gallium addition on the water splitting reaction. The effect of addition of gallium on the water splitting reaction was also studied and co-related with various concentrations of activator (0.5 N and 1.0 N aqueous KOH) and reaction temperature (50, 60 and 70 °C). The effect of gallium was found to be more prominent at 0.5 N and 50 °C as compare to the 1.0 N and higher temperatures of 50 and 60 °C. The 12 fold increase in hydrogen generation rate was observed for 0.5 N aqueous KOH at 90% gallium addition and 1.0 N aqueous KOH at 75% gallium addition. The added gallium was completely recovered from the reaction. The Shrinking Core Model has been applied to the experimental data for predicting the rate controlling mechanism. The diffusion was predicted as the rate controlling step for maximum cases.