Efficient CO₂ Removal for Ultra‐Pure CO Production by Two Hybrid Ultramicroporous Materials

Abstract

Removal of CO2 from CO gas mixtures is a necessary but challenging step during production of ultra-pure CO as processed from either steam reforming of hydrocarbons or CO2 reduction. In this contribution, two hybrid ultramicroporous materials (HUMs), SIFSIX-3-Ni and TIFSIX-2-Cu-i, which are known to exhibit strong affinity for CO2, were examined with respect to their performance for this separation. The single-gas CO sorption isotherms of these HUMs were measured for the first time and are indicative of weak affinity for CO and benchmark CO2/CO selectivity (>4000 for SIFSIX-3-Ni). This prompted us to conduct dynamic breakthrough experiments and compare performance with other porous materials. Ultra-pure CO (99.99%) was thereby obtained from CO gas mixtures containing both trace (1%) and bulk (50%) levels of CO2 in a onestep physisorption-based separation process. Carbon monoxide, CO, is a valuable reaction intermediate that is utilised for the synthesis of industrially important chemicals such as oxo-alcohols, phosgene, acetic acid and various liquid hydrocarbons.

Regulation on Topological Architectures and Gas Adsorption for Cadmium-Azolate-Carboxylate Frameworks by the Ligand Flexibility

“…Metal–organic frameworks (MOFs) as a new emerging porous material have high porosity and extraordinarily high surface area and their tunable pore size and composition are widely used in many research fields, especially in gas adsorption and separation. − Compared with rigid MOFs, flexible MOFs can produce structural transformations to external stimuli such as pressure, temperature, or guest molecules . In terms of dynamic structure, the flexibility of MOFs is caused by many factors, such as the rotation of the benzene ring in the organic ligand, the expansion and contraction of the crystal volume, and the introduction/removal of guest molecules, etc .…”

Crystal engineering of porous coordination networks for C3 hydrocarbon separation

“…An approach that we have developed to address pore size and pore chemistry is to apply crystal engineering to study platforms (families) of closely related materials, thereby allowing fine control over the both pore chemistry and pore size while retaining pore shape. Perhaps the best example to date of this approach is the development of HUM platforms 156,157 for capture of trace CO 2 53,158 and C2 HCs 50,155 …”

“…142,143 An approach that we have developed to address pore size and pore chemistry is to apply crystal engineering to study platforms (families) of closely related materials, thereby allowing fine control over the both pore chemistry and pore size while retaining pore shape. Perhaps the best example to date of this approach is the development of HUM platforms 156,157 for capture of trace CO 2 53,158 and C2 HCs. 50,155 In general, C2 and C3 HC molecules share a number of common characteristics and in both cases design principles for highly selective adsorbents are based on tailoring of pore size and pore chemistry.…”

Tunable Selectivity and High Efficiency of CO2 Electroreduction via Borate-Enhanced Molten Salt Electrolysis

“…Converting greenhouse gas CO 2 into value-added chemical fuels and functional materials is both conducive to energy storage and CO 2 mitigation, achieving a carbon-neutral energy cycle ( MacDowell et al., 2010 ). Among various CO 2 reduction reaction (CO 2 RR) approaches, electrochemical reduction processes are a simple strategy that can operate under environment-friendly conditions, especially the ones driven by renewable electricity sources (e.g., solar, wind) ( Chen et al., 2018 ; Liu et al., 2019 ). Great attentions have been paid in various species of electrolytes in recent years, such as room temperature technologies (e.g., aqueous solutions, ionic liquids) ( Chen and Mu, 2019 ; König et al., 2019 ; Rosen et al., 2011 ; Zhu et al., 2016 ), and high-temperature processes (e.g., solid oxide electrolysis cells and molten salt electrolytes) ( Jiang et al., 2019 ; Song et al., 2019 ; Wu et al., 2018 ).…”