| Porous crystal is a kind of interconnected or closed pores constitute the network structure of the crystal material,is an important branch of porous materials.Porous materials are widely used in the fields of gas storage,catalysis,energy conversion,energy storage,electro optics,gas separation,super hydrophobic interface and so on.In the past decades,people's interest in the field of porous crystals has been greatly improved,some new porous crystals are also attracting people's attention.Such as metal organic frameworks,covalent organic frameworks,porous aromatic frameworks,microporous molecular crystals and the like.Computational simulation is one of the important means to study this kind of materials.Through the calculation,the porous structure can be designed,and the adsorption properties of gases in porous materials are simulated.Compared with the rapid development of experimental work,the study of computational simulation is obviously lagging behind,the lack of force field leads to lower precision.In this work,the porous crystals are designed and the gas adsorption properties of the porous crystals are studied by multiscale simulation:1.On the basis of the recently synthesized cyclo-1,4-phenylene-2?,5?-thienylenes?[n]CPTs??Ito et al.Angew.Chem.Int.Ed.2015,54,159-163?,a set of nanoporous molecular crystals were designed,and the adsorption properties were investigated by means of Grand canonical Monte Carlo simulations,in which the force field for describing the interactions between molecules was derived from the dispersion-corrected double-hybrid density functional theory.A sufficient number of accurate reference data is used for producing the force field,which confirms the accuracy of our simulations.The results suggest that the tunable pore size of CPTs makes them suitable for practical applications of H2 or CO storage,and very interestingly,under proper conditions,they are potential candidates for purification of H2.The multiscale simulations provide new insight into the application of the novel thiophene-based CPTs in gas storage and purification.2.A novel type of porous organic frameworks,based on Mg-porphyrin,with diamondlike topology,named POF-Mgs was computationally designed,and the gas uptakes of CO2,H2,N2,and H2 O in POF-Mgs were investigated by Grand canonical Monte Carlo simulations based on first-principles derived force fields?FF?.Where the FF,which describe the interactions between POF-Mgs and gases,were fitted by dispersion corrected double-hybrid density functional theory,B2PLYP-D3.The good agreement between the obtained FF and the first-principle energies data confirmed the reliability of the FF.The results indicate that under proper conditions,[1,2]POF-Mg are potential candidates for purification of H2.Furthermore our simulation shows the presence of a small amount of H2O?? 0.01 kPa?does not much affect the adsorption quantity of CO2,but the presence of higher partial pressure of H2O??0.1 kPa?results in the CO2 adsorption decrease significantly.The good performance of POFMgs in the simulations inspires us to design novel porous materials experimentally for gasadsorption and purification.3.On the basis of experimental results,we designed a series of substituted metal organic frameworks PCN-600?Co?,in which the hydrogen atoms on the benzene and porphyrin are substituted by halogen,respectively.The gas uptakes of CO2,SO2,CH4,CO,H2 and N2 in structures were investigated by Grand canonical Monte Carlo simulations.The results showed that the amount of adsorption of SO2 and CO2 increased obviously in halogen-substituted structures.In contrast,the amount of CH4,CO,N2 and H2 adsorption capacity decreased with the halogen substituted.The selectivity investigation showed that PCN-Co-F-F has great potential in gas storage and separation,especially in the field of H2 purification. |
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