Gas storage

International audienceThe continuous increase of energy demands based on fossil fuels in the last years have lead to an increase of greenhouse gases (GHG) emission which strongly contribute to global warming. The main strategies to limit this phenomenon are related to the efficient capture of these gases and to the development of renewable energies sources with limited environmental impact. Particularly, carbon dioxide (CO2) and methane (CH4) are the main constituents of greenhouse gases while hydrogen (H2) is considered an alternative clean energy source to fossil fuels. Therefore, tremendous research to store these gases has been reported by several approaches and among them the physisorption on activated carbons (AC) have received significant attention. Their abundance, low cost and tunable porous structure and chemical functionalities with an existing wide range of precursors that includes bio-wastes make them ideal candidates for gas applications. This chapter presents the recent developments on CH4, CO2 and H2 storage by activated carbons with focus on biomass as precursor materials. An analysis of the main carbon properties affecting the AC's adsorption capacity (i.e. specific surface area, pore size and surface chemistry) is discussed in detail herein

Experimental and simulation study of the effect of surface functional groups decoration on CH4 and H2 storage capacity of microporous carbons

© 2020 Elsevier B.V. The incorporation of heteroatoms (i.e. N, O, S, F) into the microporous carbon framework is proposed to affect the interactions between adsorbates and adsorbents and improve the efficiency of gas storage. We demonstrate a facile synthesis of coal-derived activated carbons (ACs) modified with oxygen and nitrogen-containing groups for CH4 and H2 storage application. The functionalised ACs showed to have a high surface area of 1617–1924 m2/g, and pore volume of 0.85–0.92 cm3/g. The AC samples prepared by pre-oxidation followed by amination possess comparatively high CH4 adsorption capacity of 13.8 to 14.2 mmol/g at 298 K and 40 bar. However, the pristine AC and the oxidised AC showed the maximum H2 adsorption capacity with 0.6 mmol/g and 0.44 mmol/g, respectively, at 20 bar and 298 K. Density functional theory (DFT) calculations were performed to study the adsorption of CH4 and H2 on the ACs with/without the surface functional groups. In agreement with the experimental results, the computational analysis showed an increase in the gas–solid interaction after surface modification. Finally, a well-known method of Grand Canonical Monte Carlo (GCMC) was used to simulate the studied gas adsorption systems and calculate the adsorption isotherms of CH4 and H2 on different ACs