Hydrogen storage in activated carbons produced from coals of different ranks: Effect of oxygen content

• 20 activated carbons were produced by KOH activation of four rank coals.
• Activated carbons with oxygen contents from 2.2 to 10.8 wt.% were obtained.
• Porous texture is the main parameter controlling hydrogen adsorption at −196 °C.
• Oxygen content has not significant effect on hydrogen adsorption at −196 °C.

20 activated carbons (ACs) were prepared by activation of four coals of different ranks (bituminous, low-ash bituminous and sub-bituminous coals, and one anthracite) with potassium hydroxide, in order to evaluate their hydrogen storage capacities at −196 °C. The effect of surface area and oxygen content on hydrogen storage was examined. Oxygen content was determined by temperature-programmed desorption. The significance of oxygen content on hydrogen storage capacity was evaluated by Analysis of Variance (ANOVA). Apparent surface areas higher than 3000 m2 g−1 and hydrogen adsorption as high as 6.8 wt.% were obtained. The best results were obtained with ACs from bituminous coals. No significant effect of oxygen content on hydrogen adsorption was observed. We concluded that surface area controls hydrogen storage capacity at −196 °C.

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