Late-Stage Desorption Kinetics as a Design Factor for High-Productivity Cyclic Carbon Capture in Metal-Organic Frameworks

Abstract Metal–organic frameworks (MOFs) are promising adsorbents for CO2 capture, yet their evaluation has largely focused on uptake, selectivity, and adsorption kinetics, while regeneration penalties are often overlooked. Here, nine structurally diverse MOFs are evaluated under a unified adsorption–desorption protocol for simulated flue gas separation (CO2/N2 = 15/85, v/v), using the productivity of the total adsorption–desorption process (PTP) as a full-cycle metric. The results show that high CO2 uptake does not necessarily translate into high productivity when slow desorption prolongs regeneration. Within this material set, late-stage desorption diffusivity (Ddes-10) shows the strongest apparent correlation with PTP among the examined thermodynamic and kinetic descriptors. BUT-125 achieves the highest PTP of 23.2 L kg–1 h–1 despite moderate CO2 uptake, owing to rapid CO2 release enabled by its three-dimensionally interconnected pore network. These findings identify late-stage desorption kinetics as an underappreciated descriptor for designing MOF adsorbents with balanced uptake, binding affinity, pore connectivity, and regeneration kinetics for cyclic CO2 capture.