Rapid Flow Synthesis of Zr‐MOF Nanoparticles in Supercritical CO 2 for Toxic Chemical Removal
Almond Lau, Ji Feng, Vitaly L. Sushkevich, Gregory W. Peterson, Igor V. NovosselovABSTRACT
Zirconium‐based metal‐organic frameworks (Zr‐MOFs) are promising materials for the adsorption and degradation of toxic chemicals; however, their scalable synthesis is hindered by the slow formation of Zr–oxo clusters. Here, we report rapid flow synthesis of Zr‐MOF nanoparticles in supercritical carbon dioxide (scCO 2 ). Using UiO‐66 as a model system, we observe fast particle formation (17 s) and achieve 54% ± 0.28% yield in 75 s with an averaged BET surface area of 1274 ± 38 m 2 g −1 . Possible contributing factors to the fast nucleation include reduced solvent polarity, fast mass transfer, and modulated solute miscibility with the scCO 2 /DMF medium. Acid modulators appear to be critical for regulating Zr‐oxo cluster formation and the morphological transition from nanoparticle aggregates to single crystals. This strategy is extended to the synthesis of high‐quality UiO‐66‐NH 2 and MOF‐808. Products of the rapidly synthesized UiO series were evaluated for chemical warfare agent (CWA) simulant decomposition and TICs adsorption. UiO‐66‐NH 2 showed faster DMNP hydrolysis and higher NH 3 , Cl 2 , and CK uptake than UiO‐66, with performance comparable to MOFs produced by days‐long batch synthesis.