High-Throughput Computational Exploration of MOFs with Open Cu Sites for Adsorptive Separation of Hydrogen Isotopes

Abstract

Effective separation of hydrogen isotopes still remains one of the extremely challenging tasks in industry. Compared to the present methods that are energy-and cost-intensive, quantum sieving technology based on nanostructured materials offers a more efficient alternative approach, where metal−organic frameworks (MOFs) featuring open metal sites (OMS) can serve as an ideal platform. Herein, a combination of periodic density functional theory (DFT) with dispersive correction and high-throughput molecular simulation was employed from thermodynamic viewpoints to explore the D 2 /H 2 separation properties of 929 experimental MOFs bearing a copper-paddlewheel unit. The DFT calculations showed that there is a negligible rotational energy barrier for the molecule adsorbed at the OMS, and the movement of the Cu atoms along the Cu−Cu axis vector almost has no influence on the interaction energy. On the basis of the DFT results, a new force field with a proposed cutoff scheme was developed to accurately describe the strong isotope−OMS interaction. Under practical conditions (40 K and 1.0 bar), large-scale computational material screening demonstrated that the OMS interaction plays a more important role in highly selective materials and ignoring such interactions can lead to completely wrong identification of the most promising materials. Using the adsorption selectivity and adsorbent performance score as evaluation metrics, this work demonstrated that the materials with sql topology notably outperform many benchmark adsorbents reported so far.

RETRACTED: Probing the Reactions of Thiourea (CH4N2S) with Metals (X = Au, Hf, Hg, Ir, Os, W, Pt, and Re) Anchored on Fullerene Surfaces (C59X)

“…The color-filled isosurface graphs were generated from the grid points using visual molecular dynamics (VMD) software. 63 It is therefore fascinating to note that the intermolecular and intramolecular interactions caused almost all of the nine complexes to appear to be under the influence of a relatively significant force of attraction. The rich blue color visible in P1 and A1 suggests the presence of a very strong force of attraction caused by the hydrogen bond interaction, which promotes the adsorption between the surfaces and the gases.…”

“…In contrast, the strong repulsive interaction regions are known to have large positive values of λ2 and high densities (ρ > 0; λ2 > 0). The color-filled isosurface graphs were generated from the grid points using visual molecular dynamics (VMD) software . It is therefore fascinating to note that the intermolecular and intramolecular interactions caused almost all of the nine complexes to appear to be under the influence of a relatively significant force of attraction.…”

Accelerated screening and assembly of promising MOFs with open Cu sites for isobutene/isobutane separation using a data-driven approach

“…The specific C–Cu interactions were described using the Morse potential; the accuracy of this approach has been shown by Yang and colleagues. 17,32 The fitted force-field parameters of TraPPE and UFF are collected in Table S1 (ESI†). Our simulated adsorption properties of isobutene/isobutane on HKUST-1 were in agreement with reported data 15 (Fig.…”

Machine learning prediction of open metal sites in metal-organic framework catalysts

“…Open metal sites (OMS) are defined as unsaturated Lewis acid sites present on metal ions or clusters, which is used to be one of the most important performance criteria for MOFs 9 . MOFs with high density OMS have recently been reported to have better performance in the separation work, such as hydrogen isotopes 10,11 , carbon dioxide 12,13 and Xe/Kr 14 . Meanwhile, another significant function of MOFs, catalysis, also depends on the OMS 15 .…”