Highly microporous activated carbons synthesized from sacrificial templating of melamine for CH4 and H2 storages and CH4/H2 adsorptive separation

Abstract

Achieving carbon neutrality necessitates advancements in adsorbent-based gas storage technologies, particularly for maximizing the utilization of natural gas (CH4) and hydrogen (H-2) as sustainable energy sources. Activated carbons, characterized by their high surface area, stability, and cost-effectiveness, emerge as promising candidates for CH4 and H-2 storage applications. Here, we report highly microporous activated carbons prepared using sacrificial templating of melamine followed by Cs+ ion activation. The resulting activated carbon demonstrates exceptional microporous characteristics, boasting a significantly high micropore surface area (2311 m(2)/g) and micropore volume (1.070 cm(3) g(-1)). These structural attributes translate into impressive CH4 (11.92 mmol/g at 298 K and 70 bar) and H-2 (2.74 mmol/g at 298 K and 70 bar) storage capacities, underscoring its potential as a viable ambient temperature gas storage material. Furthermore, our evaluation extends to the performance of the activated carbon for adsorptive CH4/H-2 separation. The activated carbon exhibits a notable CH4 working capacity (3.13 mmol/g at 298 K, 1-10 bar pressure swing) coupled with a moderate Ideal Adsorbed Solution Theory (IAST) selectivity (25). These findings highlight the suitability of the activated carbon for both CH4 and H-2 storage applications, as well as the separation of H-2 from CH4.