• • NU-6000-OH achieves a CO2 uptake of [specific value] mmol/g at 0.4 mbar and 298 K, outperforming NU-6001-OH by [factor] and exceeding the performance of representative MOFs under identical conditions, demonstrating the critical role of pore confinement in trace CO2 capture.
• • The site efficiency, defined as CO2 molecules bound per Zn–OH site, is [value] for NU-6000-OH, compared to [value] for NU-6001-OH, indicating that spatial arrangement of active sites enhances the utilization of each binding site, which is economically significant for sorbent regeneration costs.
• • Single-crystal X-ray diffraction confirms the formation of Zn-bound bicarbonate species in NU-6000-HCO3, providing direct structural evidence of the cooperative binding mechanism, which is essential for rational design of next-generation sorbents.
• • The programmed microenvironment in NU-6000-OH enables a CO2 adsorption enthalpy of [value] kJ/mol, which is optimized for reversible capture with moderate regeneration energy, a key parameter for industrial temperature-swing adsorption processes.