Strategies for Integrated Capture and Conversion of CO₂ from Dilute Flue Gases and the Atmosphere

Abstract

The integrated capture and conversion of CO2 has the potential to make valorization of the greenhouse gas more economically competitive, by eliminating energy‐intensive regeneration processes. However, integration is hindered by the extremely low concentrations of CO2 present in the atmosphere (0.04 vol.%), and the presence of acidic gas contaminants, such as SOx and NOx, in flue gas streams. This Review summarizes the latest technological progress in the integrated capture and conversion of CO2 from dilute flue gases and atmospheric air. In particular, the Review analyzes the correlation between material properties and their capture and conversion efficiency through hydrogenation, cycloaddition, and solar thermal‐mediated electrochemical processes, with a focus on the types and quantities of product generated, in addition to their energy requirements. Prospects for commercialization are also highlighted and suggestions are made for future research.

Perspective and challenges in electrochemical approaches for reactive CO2 separations

“…The low concentration of CO 2 and presence of impurities ( Ko et al., 2020 ; Luc et al., 2019 ) in dilute feed gas streams present a barrier for direct conversion at this time. In order to solve these challenges, through improvements of catalytic electrode materials or gas introduction systems, notable results have been recently reported ( Xu et al., 2020 ; Maina et al., 2021 ; Zhao et al., 2020 ). Through this process intensification that enables direct conversion from flue gas, in combination with the electrochemical CO 2 capture strategy, significant cost reduction, and efficiency improvement can be envisioned.…”

Crosslinked porous polyimides: structure, properties and applications

“…In particular, recent focus has been placed on the direct conversion of CO 2 to useful chemicals (rather than storage). 130,131 For instance, robust and moisture-insensitive pPIs incorporating functional groups such as hydrogen-bond donors, 132,133 nucleophilic species such as pyridines, 134,135 or Lewis acidic metal centres 136,137 could serve as components of catalytic systems for the direct conversion of CO 2 and epoxides to cyclic carbonates. Further opportunities in energy conversion and storage (as touched on in Section 4.2 focusing on photocatalysis) are also available for further significant effort and exploitation.…”

Heterogeneous catalysts for the hydrogenation of amine/alkali hydroxide solvent captured CO2 to formate: A review

“…The application of integrated CO 2 capture and hydrogenation process, enabling direct hydrogenation of captured CO 2 into value-added products like FA/formate, can exclude the energy-intensive CO 2 desorption and compression steps and hence overcome the significant energy penalty in the conventional 45 CCU process. [42][43][44] The comparison of the traditional decoupled CCU process and the integrated CO 2 capture and hydrogenation process is illustrated in Fig.…”

“…1. 45 The integrated CO 2 capture and hydrogenation processes were divided into two main categories depending on the type of CO 2 capturing solvent, including alkali metal hydroxide based and aqueous amine based capturing solvent. Formate salt is typically the product obtained from hydrogenation of CO 2 and captured CO 2 in the applied aqueous phase hydrogenation process.…”