Temperature-Sensitive Carbon Capture in MOFs for Energy-Efficient Flue Gas and Biogas Purification.

Developing advanced adsorbents with both high selectivity and low regeneration energy remains a central challenge in realizing energy-efficient CO2 capture technologies. In this work, we report an ultramicroporous metal-organic framework, PCP-IPAN, designed with CO2-philic electrostatic cavities to promote strong yet thermally tunable interactions with CO2 molecules. Notably, the framework exhibits highly temperature-sensitive adsorption profiles, characterized by a sharp reduction in CO2 uptake within a narrow temperature range (273-323 K). This significant thermal sensitivity enables a large working capacity and ensures facile desorption at mild temperatures, which is a key requirement for reducing the energy penalty in pressure- and temperature-swing adsorption (P/TSA) processes. Single-component adsorption measurements reveal that PCP-IPAN-Co achieves high CO2 capacities of 4.60 and 3.32 mmol g-1 at 273 and 298 K (1.0 bar), respectively. Furthermore, it delivers CO2/N2 (15/85) IAST selectivities of 71.6 and 99.3, alongside CO2/CH4 (50/50) IAST selectivities of 39.8 and 19.6 at these temperatures. Dynamic column breakthrough experiments for CO2/N2 and CO2/CH4 binary mixtures confirm the material's excellent separation selectivity, and vacuum pressure swing adsorption (VPSA) simulations demonstrate its efficient separation energy consumption during cyclic operation. These findings highlight PCP-IPAN as an efficient platform for carbon capture.