Phosphorus and sulphur-doped microalgae carbon as a highly active metal-free catalyst for efficient hydrogen release in NaBH4 methanolysis

Abstract

Herein, sulphur (S) and phosphorus (P) doped metal-free carbon catalysts (S-KOH-S-P, S-KOH-S) based on activated carbon prepared from microalgae with KOH activation(S-KOH) were facilely prepared. The metal-free catalysts were subsequently used for efficient hydrogen release in NaBH4 methanolysis. The hydrogen generation rate (HGR) value obtained for the NaBH4 methanolysis reaction for 10 mg S-KOH-S-P metal-free catalysts was 18571 mL min−1 g−1. The activation energy (Ea) value for S-KOH-S-P was calculated to be 12.54 kJ mol−1. The high catalytic activity of P, S doped metal-free carbon catalysts was related to the synergistic effects of a porous structure and P- and S-containing active sites. The catalysts were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), X-ray diffractometer spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR) and nitrogen adsorption methods. 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.