Density functional theory meta GGA study of water adsorption in MIL-53(Cr)

Abstract

We use density functional theory meta-generalized gradient approximation TPSS + D3(BJ) + U + J calculations to investigate the energetics and geometry of water molecules in the flexible metal-organic framework material Materials of Institut Lavoisier (MIL)-53(Cr) as a function of cell volume. The critical concentration of water to cause the transition from the large pore (lp) to the narrow pore (np) structure is estimated to be about 0.13 water molecule per Cr. At a concentration x = 1 water molecule per Cr, the zero-temperature np and lp configurations each have a hydrogen bond between the H of each framework hydroxyl group and water oxygen (OW). At intermediate volumes, water dimer-like configurations are observed. A concentration x = 1.25 leads to hydrogen bonding between water molecules in the np phase that is absent for x = 1. Our results suggest possible mechanisms for pore closing in hydrated MIL-53(Cr).

Atomistic insight in the flexibility and heat transport properties of the stimuli-responsive metal–organic framework MIL-53(Al) for water-adsorption applications using molecular simulations

“…Although a substantial amount of MOFs possess a poor stability with respect to hydration, the MIL-53 family of soft porous crystals is known to have stable hydrated phases, which have been investigated both experimentally and computationally, focusing mainly on the chromium-and gallium-based variants. 51,[58][59][60][61][101][102][103][104][105][106][107][108] Here, the influence of the presence of water on the Helmholtz free energy profile of MIL-53(Al) is investigated, closely monitoring the changes in behaviour of the adsorbed species along the profile. Three different water loadings are considered: 2.5, 7.5, and 22.5 water molecules per conventional unit cell, varying from a ratio of less than one molecule per aluminium atom to almost six molecules per aluminium atom.…”

Interactions of Multiple Water Molecules with MIL-53(Al) and Understanding the Mechanism of Breathing: The DFT Study

“…The bonding by water molecules located in different places in the MIL-53 cavity is an interesting topic which was addressed by simulations. Cockayne et al 34 used DFT to find water dimers in MIL-53(Cr). Haigis et al 35 applied AIMD (ab initio molecular dynamics) to study the interaction of waters inside the narrow pore (4 water molecules) and large pore (24 water molecules) of MIL-53(Cr) using PBE density functional theory plus Grimme's correction for dispersion effects.…”

Dynamic structural and microstructural responses of a metal–organic framework type material to carbon dioxide under dual gas flow and supercritical conditions

“…The procedure here was the same as that used by Cockayne (2019). A single adsorbate molecule per asymmetric unit of the supercell was added, the structure fully relaxed, then another adsorbate molecule added and so on.…”