Tuning defects of metal–organic frameworks (MOFs) can greatly influence their performances in guest adsorption. The generation of defects in MOFs is mostly controlled under the conventional batch-heating methods, which usually cost energy and time. Herein, structural defects were rapidly constructed within dihydroxyl-functionalized UiO-66(Zr) MOF (UiO-66(Zr)-(OH)2) via an exchange reaction between a modulator molecule and bridging linker in a microwave-assisted continuous-flow tubular reactor. The linker deficiency per secondary building unit ranged from 0.60 to 2.30 upon changing the modulator concentration. The porosity and CO2 adsorption ability of the defective UiO-66(Zr)-(OH)2 adsorbent were strongly influenced by the defect concentration. The obtained results indicated that the structure-modified UiO-66(Zr)-(OH)2 containing a moderate linker deficiency amount of ~1.29 exhibited the maximum CO2 uptake amount and ideal adsorbed solution theory–predicted CO2/N2 selectivity of ~6.23 mmol g−1 and 118 (at 25 °C and 100 kPa), respectively, exceeding those of the conventionally prepared counterpart and benchmark CO2 adsorbents.
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