Salt-free synthesis of Cu-BTC metal-organic framework exhibiting mesoporosity and enhanced carbon dioxide adsorption

Cu-BTC (HKUST-1) metal-organic framework (MOF) in crystalline powder form was prepared by using a copper mesh as the metal source without involving any additional metal precursor, and its performance was evaluated for CO2 capture. The crystalline structure, morphology, textural characteristics and surface chemical properties of the synthesized HKUST-1 samples were examined by XRD, SEM, N2 physisorption, and FTIR. The MOF synthesized using the salt-free method exhibited high crystallinity, small size (-2 mu m) and uniform crystal morphology, and mesoporosity. The CO2 adsorption on the MOF was assessed at various temperatures and evaluated with respect to capacity, selectivity, kinetics, and heat of adsorption. Compared to HKUST-1 synthesized by the conventional method, the mesh-derived MOF exhibited a higher CO2 adsorption capacity (48% higher at 1 bar and 25 degrees C), increase in CO2/N2 adsorptive selectivity (-11%), as well as faster adsorption kinetics (by 73%). The heat of adsorption was found to increase as well particularly at higher coverages. The obtained CO2 uptake (-5.2 mmol/g at 1 bar and 25 degrees C) is among the highest reported for this MOF. The synthesis procedure presented here encompasses high yield (up to 85%), while it requires fewer chemicals and generates less waste compared to the solvothermal approach. As such, it holds the potential to facilitate scaled-up production in a cost-effective and greener way, as the demand for highly efficient porous materials for gas adsorption applications, including CO2 capture and H2 storage, is anticipated to significantly increase in the near future.

Automated summary

The Cu-BTC (HKUST-1) metal-organic framework prepared using a copper mesh as the metal source exhibits high CO2 adsorption capacity and efficiency, with potential for cost-effective and environmentally-friendly scaled-up production of highly efficient porous materials for gas adsorption applications in the future.