Comparative study of hydrogen storage in green synthesized porous biocarbon and N/S doped biocarbon

Abstract

The present work reports the green synthesis and hydrogen storage capacities of porous biocarbon (C_K-700) and, N/S doped biocarbon (AC_K-1) prepared by green and sustainable carbonization methods from pistachio shells. The hydrogen uptake capacity of C_K-700 and AC_K-1 were investigated at −196 °C and in the pressure range of 5–50 bar. A green and sustainable route is described for the synthesis of N/S doped biocarbon (AC_K-1) by using a combined hydrothermal carbonization and chemical activation process in which Na₂S₂O₃ applied as an activating agent. The characterization of N/S doped biocarbon and raw biocarbon were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Scanning Electron Microscopy (SEM) and Brunauer-Emmett-Teller (BET) analyses. The hydrogen storage capacities of the green synthesized C_K-700 and AC_K-1 were measured by IGA dynamic gas adsorption analyzer. The hydrogen adsorption capacity of C_K-700 and AC_K-1 were measured and, the highest hydrogen adsorption capacity of AC_K-1 was obtained to be 4.55 wt% under pressure of 50 and at 73 K, while the lowest hydrogen uptake capacity of C_K-700 was obtained to be 2.24 wt% under pressure of 5 bar and at 73 K in raw biocarbon.

HIGHLIGHTS

• Hydrogen storage capacity of the green synthesized porous biocarbon and N/S doped porous biocarbon were studied.

• Biocarbon nanoparticles were prepared via green and sustainable method.

• The addition of sodium thiosulfate as a nontoxic agents plays a synergetic catalytic role.

• Increase of pore sizes around 765 m²/g in porous N/S doped biocarbon essential for the enhanced hydrogen adsorption.

Keywords:

• Hydrogen storage
• biocarbon
• green synthesis
• physisorption

Disclosure statement

The author declares that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.