Investigation of Hydrogen Production from Sodium Borohydride Methanolysis in the Presence of $Al_2O_3$ /Spirulina Platensis Supported Co Catalyst

Abstract

In this study, $Al_2O_3$/Spirulina Platensis mixture was used for the first as support material. The aim is to demonstrate that microalgaecan be used as a new, economic and environmental support agent to increase the efficiency of the catalysts that will be eventually usedin the production of hydrogen. The strain was grown by preparing the culture medium containing all the necessary nutrients asdescribed in the literature. To synthesize the catalyst for the production of hydrogen through methanolysis of sodium borohydride($NaBH_4$), phosphoric acid ($3M\\;H_3PO_4$) was used as the protonation agent for the selected strain. After achieving sufficient density, thestrain was dried and mixed with $Al_2O_3$ in the ratio of 1/1. Modified $Al_2O_3$/S. Platensis mixture was finally blended with cobalt ionsand the mixture was burned. As a result of this procedure $Al_2O_3$/S. Platensis supported Co catalyst was produced. The catalyst wasprepared with the addition of different $Co^{2+}$ metal concentrations, 10%, 20%, 30%, and 40% respectively. In the present study, theexperiments were generally carried out with 10 ml methanol solution containing in 0.025 g $NaBH_4$ with 0.1 g catalyst at 30 °C. Thehydrogen obtained in experimental studies was determined volumetric in the gas measurement system. Here, different NaBH4concentrations, catalyst amount and different temperature effects were investigated. The effect of the amount of NaBH4 wasinvestigated with 1%, 2.5%, 5%, and 7.5% ratio of NaBH4 while the influence of the concentration of catalyst was carried out 0.05,0.1, 0.15, and 0.25 g catalysts. To investigate the performance of the catalyst on hydrogen production with NaBH4 methanolysis underdifferent temperatures, 30, 40, 50 ve 60 °C, relatively. The experiments by using $Al_2O_3$/S. Platensis supported Co Catalyst reveal thatthe best metal ratio was 10% Co2+. In addition, the maximum hydrogen production rate through methanolysis reaction of $NaBH_4$ bythis catalyst was found to be 5747.1 mL $min^{-1}gcat^{-1}$. Also, the activation energy was determined to be 34.67 kJ $mol^{-1}$. Moreover,different $NaBH_4$ concentrations, catalyst amounts and temperature studies of the fabricated catalyst were carried and it was discoveredthat there was no decline in the % of conversion for the synthesized catalyst.