Effect of altering linker ratio on nano-ZIF-8 polymorphisms in water-based and modulator-free synthesis

• Published in: Journal of coordination chemistry Vol. 75; no. 9-10; pp. 1180 - 1192
• Main Authors: Hamidon, Noor Fazrieyana, Tahir, Mohamed Ibrahim Mohamed, Latif, Muhammad Alif Mohamad, Abdul Rahman, Mohd Basyaruddin
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 22.09.2022; Taylor & Francis Ltd
• Subjects: Absorption; Carbon dioxide; Metal-organic frameworks; modulator free; nanomaterial; Phase transitions; Room temperature; Synthesis; Thermal analysis; Thermal stability; Thermogravimetric analysis; water-based; X ray powder diffraction; Zeolites; Zeolitic imidazolate frameworks
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2022.2100990

A transition between a micron-leaf-like structure (ZIF-L) at room temperature to the nano-zeolitic imidazolate framework-8 (n-ZIF-8) was produced by using a water-based synthesis without modulating agents. Polymorphisms of ZIF structures were produced in an hour by mixing varying molar ratios of 2-methylimidazole and zinc nitrate hexahydrate (8:1, 21:1, and 35:1). The polymorphic phase transition of the ZIFs was identified using powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), and surface and pore characteristics from a nitrogen adsorption analyzer. The sizes of the particles range from micron to nano (ZIF-L = 2 µm, n 21 ZIF-8 = 400 nm, and n 35 ZIF-8 = 100 nm). The n 35 -ZIF-8 has amongst the highest surface area of any ZIF-8 currently reported, with approximately 1776 m 2 g −1 and is thermally stable up to 400 °C. Meanwhile, n 21 ZIF-8 demonstrated the greatest CO 2 absorption capacity by absorbing up to 22.71 mmolg −1 of CO 2 at 273 K.