Synthesis of Cu-BTC Metal-Organic Framework for CO2 Capture via Solvent-free Method: Effect of Metal Precursor and Molar Ratio

Abstract

The Cu-BTC (Copper-1,3,5-benzene tricarboxylate) is one of the representative metal organic frameworks (MOFs) that has shown outstanding performance for carbon dioxide (CO₂) adsorption. However, its conventional synthesis duration is relatively long, and the process requires the addition of bulk amounts of organic solvents. Herein, an enhanced solvent-free synthesis strategy was demonstrated in this work for the Cu-BTC synthesis. For this enhanced method, Cu-BTC was synthesized in 3 hours by mechanically grinding the mixture of copper (Cu) metal precursor and BTC organic linker without using solvent. The as-synthesized Cu-BTC samples were analyzed using various characterization techniques to examine and confirm their properties. The thermal stability result revealed that the self-synthesized Cu-BTC could sustain high temperature up to 290°C. Among the samples synthesized at different mole ratios, the Cu-BTC sample with the Cu to BTC mole ratio of 1.5:1 showed the highest BET surface area and the most significant pore volume of 1044 m² g^–1 and 0.62 cm³ g^–1, respectively. Its CO₂ adsorption capacity was comparable with those fabricated using the solvent-based method, i.e., 1.7 mmol g^–1 at 30°C and 1 bar. The results also showed that the synthesized Cu-BTC exhibited regenerative ability up to five adsorption-desorption cycles.