Extended Data Fig. 7: Silicalite-1 and ZIF-67 atomistic MD simulations.

The H₂O (a) and O₂ (b) densities inside a silicalite-1 nanocrystal filled with 2,270 mmol l⁻¹ H₂O molecules at t = 0. Note that, after addition of an initial 3,500 H₂O molecules, the system was thermalized for 1 ns before beginning the production run shown above. This initial loading of 3,500 H₂O molecules inside the nanocrystal corresponds to a starting H₂O concentration of 8,600 mmol l⁻¹. The thermodynamic driving force for water expulsion is so large that about 74% of the H₂O molecules leave before starting the production run. The residual water at the end of the simulation represents less than 2% of the total micropore volume. Atomistic simulation of O₂ adsorption inside ZIF-67 surrounded by liquid water is depicted in c, with snapshots of the simulation shown at 0 ns and 600 ns. ZIF-67 is coloured in black, O₂ in red and OH⁻ in green. ZIF-67 hydrogen atoms are omitted for clarity. The simulation box is indicated by solid black lines. The equilibrium concentration profiles of O₂ and water are shown in d, with the shadows representing the standard deviations from four blocks of 100-ns simulations. The relative densities in the gas phase, in the water phase and inside ZIF-67 support that the adsorption of water molecules by ZIF-67 is energetically unfavoured, whereas O₂ adsorption is favoured. A simulation of the protein BSA adsorbing on the surface of ZIF-67 is illustrated in e. Water is represented as a semi-transparent volume in light blue. f, Calculation of the interaction energy between the protein and ZIF-67. The Coulomb and Lennard-Jones components of the interaction between ZIF-67 and BSA show that the Coulomb interactions dominate.