Abstract

With increasing energy demand and fast-paced decarbonization methods adopted to curb the adverse effects of greenhouse gas emissions, hydrogen (H2) is considered a sustainable, clean, and potential renewable energy carrier for the future. To substitute the energy needs required for the physical methods of H2 storage, adsorbed gas storage (AGS) is the next viable option that provides the opportunity to adsorb and desorb gases under mild conditions. In this work, we studied the effect of light alkali metal functionalization comprising Li and K on the H2 storage performance of porous graphitic carbon adsorbents. The effect of metal doping on the enthalpy of adsorption and the enhancement of H2 uptake were systematically investigated. The results showed an enhancement in the gravimetric uptake up to 2.8 wt % at room temperature and 100 bar pressure for Li-doped carbon at 2.5 wt % of Li metal loading through the enhanced electrostatic interactions. The isosteric heat of adsorption increased from 8.3 to 11.7 kJ/mol, suggesting that the dispersed alkali cations in the form of alkoxide (O-Li) species act as active centers capable of anchoring H2 molecules through electrostatic charge-quadrupole and charge-induced dipole interactions. Furthermore, the Li intercalation was found to increase the interlayer distance from 3.87 to 4.09 Å. The findings of this study demonstrate that the Li-doped carbon at 2.5 wt % loading exhibits superior H2 storage performance compared to other alkali metal-doped carbon analogues.

Department(s)

Chemical and Biochemical Engineering

International Standard Serial Number (ISSN)

1520-5029; 0887-0624

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2023 American Chemical Society, All rights reserved.

Publication Date

01 Jan 2023

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