Interfacial assembled preparation of porous carbon composites for selective CO2 capture at elevated temperatures

Abstract

Development of porous sorbents that can selectively capture carbon dioxide (CO₂) through adsorption technology from the flue gas is essential to reduce emission of CO₂ to the atmosphere. However, under typical flue gas conditions (∼0.15 bar of CO₂ at 40–70 °C), the adsorption capacity and selectivity for CO₂ over those for nitrogen (N₂) remain poor on traditional porous adsorbents due to weak adsorbent–adsorbate interactions. Here, we report the synthesis of hierarchically structured porous carbon composites via an interfacial assembling strategy using nanoclay LAPONITE®, resorcinol and formaldehyde as the precursors. This fabrication strategy allows fine tuning of the surface chemistry and pore network of porous carbons with the aim of enhancing the CO₂ capture capacity at elevated temperatures (e.g., 50–150 °C). The obtained carbon composites reach a record-high CO₂/N₂ selectivity (114.3) at 70 °C, according to equilibrium gas adsorption analysis and dynamic breakthrough measurement associated with a high adsorption capacity of 1.7 mmol g⁻¹ at 1.1 bar and 70 °C, and 0.5 mmol g⁻¹ at 0.17 bar and 70 °C. The inorganic substance integrated 3D carbon framework is responsible for such superior CO₂ capture at 70 °C by enhancing adsorbent–adsorbate interactions.