LAUSR

Abstract Metal-free catalysts (C–KOH–P) containing phosphorus (P) and oxygen (O) prepared by the modification with phosphoric acid (H3PO4) of activated carbon (C–KOH) obtained by activation of Chlorella Vulgaris microalgae with potassium hydroxide (KOH) were investigated for the hydrogen (H2) generation reaction from methanolysis of sodium borohydride (NaBH4). Elemental analysis, XRD, FTIR, ICP-MS, and nitrogen adsorption were used to analyze the characteristics of metal-free catalysts. The results showed that groups containing O and P were attached to the carbon sample. In the study, the hydrogen production rates (HGR) obtained with metal-free C–KOH and C–KOH–P catalysts were 3250 and 10,263 mL/min/g, respectively. These HGR values are better than most values obtained for many catalysts presented in the literature. Besides, relatively low activation energy (Ea) of 27.9 kJ/mol was obtained for this metal-free catalyst. The C–KOH–P metal-free catalyst showed ideal reusability with 100% conversion and a partial reduction in the H2 production studies of NaBH4 methanolysis after five consecutive uses.