Effect of varying cosolvent on the properties and performance of ZIF-8 for recyclable CO₂ adsorption and storage

CO₂ capture and storage is central to the global warming crisis. A range of technologies is under development, including adsorption, cryogenic separation, and sequestration, for the capture, storage, or utilization of CO₂. Among these, the use of Metal-Organic Framework nanomaterial adsorbents is promising due to their ability to efficiently separate and store CO₂. Here, ZIF-8 nanocrystals were prepared using a facile, one-pot, room temperature cosolvent-based hydrothermal route. This method significantly reduced total cosolvent and ligand consumption (from a ligand (L)/metal (M) ratio of 70 to 8), resulting in a more environmentally friendly and economically viable synthesis. ZIF-8 crystals were prepared using a range of common organic cosolvents, and systematic studies were performed to investigate the influence of cosolvent on their properties. These included crystal phase, crystallinity, molecular structure, bonding type, elemental composition, surface area, and pore volume. The cosolvent-based ZIF-8 samples exhibited excellent thermal stability in both nitrogen and air environments. They also showed impressive CO2 adsorption capacities in adsorption isotherm (0.81 mmol g⁻¹ at 25 °C and 100 kPa for ZIF-8_Methanol) and thermogravimetric (∼2.50 wt%/0.57 mmol g⁻¹ for ZIF-8_n-hexane) experiments, with excellent recyclability. This study provides a guide for preparing suitable ZIF-8 materials for adsorption and related applications.