Nanowire-like C2H2 assembly in a flow-channel crystal boosts C2H2/CO2 separation at 348 K.

Efficient adsorptive separation of acetylene (C2H2) from carbon dioxide (CO2) at elevated temperatures, which signifies saved energy consumption, remains a formidable challenge due to the thermal instability of host-guest interactions in conventional adsorbents. Inspired by the stability of linear molecular assemblies observed in polymer systems, we report a microporous crystal, NTU-103, whose one-dimensional (1D) helical flow-channel shapes adsorbed C2H2 molecules into a "nanowire"-like structure stabilized by synergistic host-guest and guest-guest interactions at 348 K, while isolating CO2. This unique confinement mechanism, confirmed by varied-temperature in-situ crystallographic, infrared spectroscopic analyses and modeling calculations, enables the robust NTU-103 to achieve a high C2H2/CO2 selectivity (up to 96) and cyclable breakthrough separation performance at industrially preferred conditions (348 K). This work addresses a key challenge of high-temperature separation, and provides fundamental insights into shaped gas nanostructures for advancing porous materials targeting challenging separations with minimal energy input.