Highly active and durable hydrogen release in NaBH4 methanolysis reaction with sulphur and phosphorus-doped metal-free microalgal carbon nanoparticles

Herein, activated carbons prepared from microalgae with KOH activation (C-KOH) used for sulphur (S) and phosphorus (P) doped metal-free carbon catalysts (C-KOH-S-P, C-KOH-S) for the first time with hydrogen release in NaBH4 methanolysis reaction (NaBH4-MR). The metal-free carbon catalysts were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM-EDS), X-ray diffractometer spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), nitrogen adsorption, and elemental analysis (CHNS) methods. Hydrogen generation rate (HGR) for the NaBH4-MR for C-KOH-S-P metal-free catalyst (10 mg) was 13,000 mL min-1 g-1. The activation energy (Ea) value for C-KOH-S-P was found to be 25.02 kJ mol-1. For the C-KOH-S-P catalyst, about 59 % of the first catalytic activity was retained after the fifth run. A new strategy with the S and P doped metal-free carbon catalysts obtained in this study can be provided for environmentally friendly efficient catalytic reactions.

Automated summary

In this study, activated carbons prepared from microalgae with KOH activation were used for the first time as sulphur (S) and phosphorus (P) doped metal-free carbon catalysts in NaBH4 methanolysis reaction, showing a high hydrogen generation rate and low activation energy. After five cycles, the catalyst retained 59% of its initial catalytic activity, demonstrating the potential for environmentally friendly efficient catalytic reactions.