Grand canonical Monte Carlo simulations in conjunction with high-resolution low-pressure argon adsorption experiments were employed to study adsorption mechanisms on the copper(II) benzene-1,3,5-tricarboxylate metal-organic framework (Cu-BTC). We constructed a molecular structural model of Cu-BTC. The pore network of Cu-BTC has a simple cubic symmetry. It consists of main channels of a square cross-section of ca. 0.9 nm diameter and tetrahedral side pockets of ca. 0.5 nm, which are connected to the main channels by triangular windows of ca. 0.35 nm diameter. Using a parameterized united-atom force field, we have determined the preferential adsorption sites and the sequence of adsorption mechanisms from a gradual filling of the side pockets to a stepwise adsorption and condensation in the main channels. The simulation results agree quantitatively with the experimental isotherm of argon up to almost complete filling of the pore network.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanical Engineering