ZIF-8 with exceptional thermal stability: Role of organic cosolvents in phase control and structure stabilization

作者：Fraz Saeed Butt, Allana Lewis, Fergus Dingwall, Nurul A. Mazlan, Norbert Radacsi, Xianfeng Fan, Xianfeng Chen, Yaohao Yang, Shuiqing Yang, Yi Huang · 发表于：Materials Today Chemistry · 年份：2023 · DOI：10.1016/j.mtchem.2023.101804 · 被引用次数：26 · 研究领域：Metal-Organic Frameworks: Synthesis and Applications、Corrosion Behavior and Inhibition、Crystallography and molecular interactions

Thermal stability is one of the key factors in catalysis and high-temperature industrial applications. The thermal degradation of ZIF-8, particularly its nanocrystals, could result in a significant loss of surface area and crystallinity, limiting its large-scale applicability. In this study, ZIF-8 nanocrystals with improved thermal stability were synthesized at room temperature (RT) through a facile, one-pot method – an ultrasound-assisted, solvent-guided ZIF-8 growth. The effect of synthesis variables, including the type and concentration of solvent, ultrasonication, and synthesis time, in improving the material’s thermal stability was studied systematically. The as-prepared samples were analyzed by TGA/DSC, XRD, SEM/TEM, FTIR, and BET to monitor the weight loss with temperature, sample crystallinity, crystal morphology, chemical structure, and surface area. Notably, synthesis with 5 v/v% of n-hexane (ZIF-8new-ref) demonstrated the formation of highly-crystalline ZIF-8 nanocrystals with extraordinary thermal stability (with only ∼2.0–3.0 % weight loss up to 600 °C), large surface area (i.e., 975 m2 g−1), and an excellent particle size distribution in the range of 0.2–0.4 μm. More importantly, the short synthesis time (2 h) and sonication-assisted pretreatment of the precursor (for promoting solvent-ligand interaction) proved effective and played a crucial role in controlling ZIF-8’s thermal stability. The mechanism for the thermal stability enhancement was thus proposed. The...