Peat-Derived ZnCl₂-Activated Ultramicroporous Carbon Materials for Hydrogen Adsorption

Highly microporous adsorbents have been under considerable scrutiny for efficient adsorptive storage of H₂. Of specific interest are sustainable, chemically activated, microporous carbon adsorbents, especially from renewable and organic precursor materials. In this article, six peat-derived microporous carbon materials were synthesized by chemical activation with ZnCl₂. N₂ and CO₂ gas adsorption data were measured and simultaneously fitted with the 2D-NLDFT-HS model. Thus, based on the obtained results, the use of a low ratio of ZnCl₂ for chemical activation of peat-derived carbon yields highly ultramicroporous carbons which are able to adsorb up to 83% of the maximal adsorbed amount of adsorbed H₂ already at 1 bar at 77 K. This is accompanied by the high ratio of micropores, 99%, even at high specific surface area of 1260 m² g^-1, exhibited by the peat-derived carbon activated at 973 K using a 1:2 ZnCl₂ to peat mass ratio. These results show the potential of using low concentrations of ZnCl₂ as an activating agent to synthesize highly ultramicroporous carbon materials with suitable pore characteristics for the efficient low-pressure adsorption of H₂.