https://doi.org/10.1016/j.cej.2021.131574
“We started with the hypoCOF database which consists of 69,840 structures [28]. HypoCOF structures were named as linkerA_linkerB_net_interp_#, where “A” and “B” denote the linkers and their respective linker terminations, “net” represents the topology and “#” shows the degree of interpenetration, if the structure is catenated [28]. The corresponding IUPAC (International Union of Pure and Applied Chemistry) [33] names of all linkers together with their three dimensional representations were available in the literature [28]. We computed the largest cavity diameter (LCD), accessible surface area (Sacc), density (ρ), and porosity (ϕ) values using Zeo++ software (version 0.3) [34]. Blind screening of all hypoCOFs is time-consuming due to the very large number of materials. Therefore, we performed a directed computational screening methodology as represented in Fig. 1, considering our recent results from the computational screening of 288 CoRE COFs (experimentally synthesized COFs) for adsorption-based and membrane-based CO2/H2 separation [27]. It was previously demonstrated that COF adsorbents with LCD < 15 Å and ϕ < 0.75 and COF membranes with LCD > 20 Å and ϕ > 0.85 outperform other CoRE COFs for CO2/H2 separation. Based on this outcome, two hypoCOF subsets, hypoCOF-A for adsorbents and hypoCOF-M for membranes, were constructed by filtering the materials considering their LCD and ϕ as shown in Fig. 1. For hypoCOF-A set, 3184 materials with LCD < 15 Å and ϕ < 0.75 were selected. For hypoCOF-M set, we selected 794 hypoCOFs with LCD and ϕ in the ranges of 50–85.7 Å and 0.90–0.99, respectively. Fig. 2 shows the LCD and ϕ distribution of hypoCOF-A and hypoCOF-M sets in addition to those of 288 CoRE COFs. We examined several chemical descriptors of COFs, including dimensionality (D), linker and bond types, and topological nets. HypoCOF-A set consists of 388 2D and 2796 3D materials with LCD < 15 Å and ϕ < 0.75 whereas hypoCOF-M set includes 229 2D and 565 3D materials with LCD > 50 Å and ϕ > 0.9. In hypoCOF-A (hypoCOF-M) set, there are 154 (30) different topological nets and 111 (95) linker types. Structural properties of all hypoCOFs studied in this work, together with their topology, linker, dimensionality information, and schematic representations of the linkers that we discussed throughout this study are provided in an excel file as Supplementary Information (SI).”
“Fig. 1. Directed computational screening of hypoCOFs for adsorption-based and membrane-based CO2/H2 separation.”
“Fig. 2. Porosity and LCD comparison of hypoCOF-A and hypoCOF-M sets with CoRE COFs.”