Deciphering Mechanisms of CO₂-Selective Recognition over Acetylene within Porous Materials

Reverse adsorption of carbon dioxide (CO₂) from acetylene (C₂H₂) presents both significant importance and formidable challenges, particularly in the context of carbon capture, energy efficiency, and environmental sustainability. In this Review, we delve into the burgeoning field of reverse CO₂/C₂H₂ adsorption and separation, underscoring the absence of a cohesive materials design strategy and a comprehensive understanding of the CO₂-selective capture mechanisms from C₂H₂, in contrast to the quite mature methodologies available for C₂H₂-selective adsorption. Focusing on porous materials, the latest advancements in CO₂-selective recognition mechanisms are highlighted. The review establishes that the efficacy of CO₂ recognition from C₂H₂ relies intricately on a myriad of factors, including pore architecture, framework flexibility, functional group interactions, and dynamic responsive behaviors under operating conditions. It is noted that achieving selectivity extends beyond physical sieving, necessitating meticulous adjustments in pore chemistry to exploit the subtle differences between CO₂ and C₂H₂. This comprehensive overview seeks to enhance the understanding of CO₂-selective recognition mechanisms, integrating essential insights crucial for the advancement of future materials. It also lays the groundwork for innovative porous materials in CO₂/C₂H₂ separation, addressing the pressing demand for more efficient molecular recognition within gas separation technologies.