Synthesis of rice husk activated carbon by fermentation osmotic activation method for hydrogen storage at room temperature

In the present study, an innovative method of fermentation osmotic activation was employed to produce activated carbon derived from rice husk. The fermentation procedure dismantles the robust lignin present on the rice husk surface, thereby liberating amorphous SiO2, enhances osmotic activation, and promotes pore development. Following the high-temperature osmosis treatment utilizing a KOH solution, a significant portion of the amorphous SiO2 on the husk's surface is successfully dissolved and removed, leading to the formation of numerous carbon skeletons. This procedure culminates in the production of activated carbon characterized by a high specific surface area and substantial pore volume, attributed to the role of K ions during carbonization. The sample DFRO1-AC exhibited the most effective hydrogen gravimetric storage capacity of 1.21 wt% at room temperature (25 °C) and 80 bar pressure, featuring a BET specific surface area of 2270 m2/g. Compared to other activated carbons used for hydrogen storage, our materials demonstrate superior hydrogen storage capacity and employ renewable agricultural waste, indicating high feasibility and broad application prospects.