Hydrogen Storage on Food Waste Derived Superactivated Hydrochars

Background/Question/Methods

In an effort of developing hydrogen storage material, this study explored food waste (FW) to develop porous carbon materials with remarkable hydrogen storage. Simulated FW was hydrothermally carbonized at 220 ◦C followed by chemical activation at 800 ◦C using various KOH-to-FW hydrochar ratio. The solid superactivated hydrochars, were characterized by proximate and ultimate analyses as well as X-ray diffractometer (XRD) and through nitrogen adsorption isotherms at 77 K to analyze the changes in the material including its surface porosity parameters (surface area, pore volume, and pore size distribution) as the FW underwent chemical and morphological modifications. The gravimetric hydrogen storage capacity of the superactivated hydrochars were then conducted under 77 K and various pressure of 0–23 bar. Results showed that the surface area and total pore volume in the superactivated hydrochars were in the range of, as high as, 2070 to 2885 m2/g and 0.98 to 1.93 cm3/g, respectively.

Results/Conclusions

The remarkable hydrogen storage was observed of as high as 6.15 wt% at 23 bar and 77 K for the superactivated hydrochar produced with a KOH to FW hydrochar ratio of 4:1. This distinctly highlights the pertinent upcycling technique of food waste to be effective in developing efficient hydrogen storage material.