Hydrogen storage in CO2-activated amorphous nanofibers and their monoliths

Abstract

Amorphous carbon nanofibers (CNFs), produced by the polymer blend technique, are activated by CO 2 (ACNFs). Monoliths are synthesized from the precursor and from some ACNFs. Morphology and textural properties of these materials are studied. When compared with other activating agents (steam and alkaline hydroxides), CO 2 activation renders suitable yields and, contrarily to most other precursors, turns out to be advantageous for developing and controlling their narrow microporosity (< 0.7 nm), V DR (CO 2 ). The obtained ACNFs have a high compressibility and, consequently, a high packing density under mechanical pressure which can also be maintained upon monolith synthesis. H 2 adsorption is measured at two different conditions (77 K / 0.11 MPa, and 298 K / 20 MPa) and compared with other activated carbons. Under both conditions, H 2 uptake depends on the narrow microporosity of the prepared ACNFs. Interestingly, at room temperature these ACNFs perform better than other activated carbons, despite their lower porosity developments. At 298 K they reach a H 2 adsorption capacity as high as 1.3 wt.%, and a remarkable value of 1 wt.% in its mechanically resistant monolith form.

CO2 activation of olive bagasse for hydrogen storage

“…Surprisingly, OB‐CO 2 sample has outperformed nanoporous materials with higher specific surface area , which reveals that surface area is not the only parameter that needs to be regarded. Even though, many investigators have shown that, at 77K and subatmospheic pressures, the hydrogen uptake was governed by the microporosity and the specific surface area of the tested adsorbents . Actually, the only exceptional feature of OB‐CO 2 sample is its ultramicroporous character, with a well ordered pore system centered at 0.65 nm.…”

Chitosan-based highly activated carbons for hydrogen storage

“…Although hydrogen adsorption in ACs at ambient temperature is relatively low even at high pressures [3e5] due to the low quadrupole moment and the low polarizability of the H 2 molecule [4], hydrogen cryosorption is considered to be a promising method for hydrogen storage, as ACs can reversibly adsorb substantial quantities of hydrogen with fast adsorption/ desorption kinetics [6,7]. The porous texture is the main feature determining the hydrogen adsorption capacity of ACs.…”

Adsorbent density impact on gas storage capacities

“…Porous materials like activated or templated carbons [1][2][3][4], metal-organic frameworks (MOFs) [5,6], covalent organic frameworks (COFs) [7], etc. are interesting candidates for gas storage application [8][9][10].…”