Spirulina microalgal strain as efficient a metal-free catalyst to generate hydrogen via methanolysis of sodium borohydride

Abstract

Metal-free catalyst based on Spirulina platensis microalgae (SPM) is protonated by phosphoric acid (H3PO4) treatment (SPM-H3PO4). The microalgae sample is then exposed to heating with different temperatures including 200, 300, and 400 degrees C (SPM-H3PO4-H). The modified microalgae sample based on Spirulina platensis as a catalyst is directly used to generate hydrogen via the methanolysis of sodium borohydride (MSB). The activation temperature, activation time, NaBH4 concentration, catalyst amounts, temperature and reusability tests were carried out. The maximum hydrogen production rates (HGR) obtained for SPM-H3PO4-H at temperatures of 30 degrees C and 60 degrees C were 3975 and 9600 mLmin(-1)gcat(-1), respectively. At the same time, the activation energy(Ea) of 17.78 kJ mol(-1) was obtained. Reusability experiments were performed for this microalgae-based metal-free catalyst. XRD, SEM, FTIR, BET, and TEM analyzes were performed for characterization of these metal-free catalyst samples.