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The excessive emission of CO 2 causes severe environmental problems. Sustainable CO 2 management based on carbon capture and utilization plays important role in addressing emission-control issue. Among various routes, synergistic coupling between CO 2 capture and conversion brings prospects for energy conservation by simultaneously avoiding the energy-intensive regeneration, compression and transportation steps in conventional sequential pathway. Herein, this review summarizes the state-of-the-art progress in promising materials for integrated capture and conversion of CO 2 in terms of electrochemical CO 2 reduction and thermochemical CO 2 hydrogenation. The integrated electrochemical process eliminates the critical issues faced by CO 2 gas-fed electrolysers, and integrated thermochemical process performing in a single reactor under isothermal conditions benefits from lower energy consumption and less capital investment. Rational design and precise manipulation of key adsorbents/absorbents and catalysts and the influence of interactions between them are discussed. Several considerations are put forward from industrial application perspectives and potential development directions of materials and systems that boost the high selectivity towards valuable products. This review highlights the major challenges and emerging opportunities in integrated CO 2 capture and utilization systems, which provides guidance for future investigations. • Sustainable CO 2 management based on carbon capture and utilization is vital for emission-control. • Integrated CO 2 capture and conversion can make the overall process more energy efficient. • The coupling between capture and conversion, electrocatalysts, and dual-functional materials are systematically discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A machine learning-based approach to design ionic liquids (ILs) promising toward the desired target applications. • A tailor-made design of ILs for two cases of CO 2 capture from 1) flue gas (CO 2 /N 2) and 2) from syngas (CO 2 /H 2) • Great efficiency in designing high-performance ILs using our algorithm. • Assessment on the ability of our algorithm to find high-performing ILs with good diversity. In this article, we present a machine learning-based approach for the tailor-made design of ionic liquids (ILs) promising toward the desired target applications. Our computational framework combines multi-player Monte Carlo tree search and recurrent neural network, within a parallel scheme of generating and testing multiple ILs simultaneously, to improve the efficiency of searching optimal structures. For two cases of CO 2 capture from 1) flue gas (CO 2 /N 2) and 2) from syngas (CO 2 /H 2), target-specific ILs were generated in our computational platform according to objective function values that combine three requirements of high CO 2 solubility, absorption selectivity of IL for CO 2 , and easiness of subsequent desorption. Our results showed that high-performance ILs can be designed with great efficiency using our algorithm. Furthermore, topological data analysis on newly designed ILs demonstrated that our algorithm allows us to explore materials space widely to find high-performing ILs with good diversity. [ABSTRACT FROM AUTHOR]

A comprehensive computational study was performed to develop zeolite-templated carbon (ZTC) materials for efficient carbon dioxide (CO 2) and nitrogen (N 2) separation. From the previously reported ZTC structure library, our screening based on the grand canonical Monte Carlo simulations identified the types of top ZTCs having high selectivity ( S C O 2 / N 2 ) of CO 2 over N 2. A detailed investigation about pore structure-property relationship elucidated that high S C O 2 / N 2 is attributed to the strong confinement effect on CO 2 gas molecules in small pores. Furthermore, with an attempt to further improve S C O 2 / N 2 , we investigated two approaches which are nitrogen doping and ionic liquid incorporation. Our simulations predicted that nitrogen-doped or ionic liquid incorporated ZTCs exhibited enhanced S C O 2 / N 2 , due to strong interaction between CO 2 and negatively charged nitrogen atom or anions in ionic liquid, respectively. While both approaches have provided promises in upgrading ZTCs for high S C O 2 / N 2 , observation of the exceptional cases which showed insignificant changes in S C O 2 / N 2 suggested that design strategy might be altered in accordance with the structural feature of ZTC, representatively, pore topology. Our case study for ZTC-IRR demonstrates that a strategy devised with a deep understanding of pore topology can significantly improve S C O 2 / N 2 of ZTC. Image 1 • Various Zeolite-Templated Carbon structures are studied for CO 2 and N 2 separation. • Adsorption of CO2 and N2 in ZTCs are simulated via Grand Canonical Monte Carlo. • Nitrogen doping results in an increase of selectivity of CO 2 over N 2 in ZTCs. • ZTCs with ionic liquids have enhanced the selectivity of CO 2 over N 2. • The importance of understanding pore topology is addressed for designing a strategy of high performing ZTCs. [ABSTRACT FROM AUTHOR]

• A single-atom catalyst with ultrathin nanosheet structure and high Ni loading of 5.92 wt%. • High catalytic performance with CO Faradaic efficiency over 95 % in a wide potential range. • Remarkable CO yields up to 1146 mmol g cat –1 h–1. • Unveiling modulation effect of the electronic configuration of Ni-N 4 active sites by F-doping. A fluorine-tuned single-atom catalyst with an ultrathin nanosheet morphology (only ∼1.25 nm) and high Ni content of 5.92 wt% was fabricated by a polymer-assisted pyrolysis approach. The synthetic approach not only controls the establishment of the ultrathin nanosheet structure for achieving high surface communication, but also incorporates F dopants to manipulate the electronic structure of the metalloporphyrin-like active sites (Ni-N 4). As a result, such catalyst with unique structural features exhibits a remarkable electrocatalytic performance for CO 2 -to-CO conversion with the Faradaic efficiency (FE) over 95 % in a wide potential range and an outstanding CO evolution rate of 1146 mmol g cat –1 h–1 at –0.97 V vs. RHE. The in situ attenuated total reflection-infrared spectroscopy (ATR-IR) and theoretical calculations further demonstrate that the F-doping modulates the electron configuration of the central Ni-N 4 sites and thereby reduces the energy barrier for CO 2 activation, which is favorable to the generation of the key *COOH intermediate. [ABSTRACT FROM AUTHOR]

• Mesoporous carbon nanoframes embedded with single Fe atoms. • Superior ORR catalytic performance than the benchmark 20 wt% Pt/C. • The Zn–air battery based on the catalyst exhibits a good performance. • Remarkable activity and selectivity for CO 2 reduction to CO. Metal–organic frameworks (MOFs) can be utilized as superior precursors to pyrolytically achieve the single-atom catalysts. However, most of the atomic active sites are buried inside the microporous carbon matrix, which severely impedes the accessibility of active sites and limits mass transport. Herein, the mesoporous carbon nanoframes with hierarchical pore size distribution and atomically dispersed Fe–N x active sites were synthesized from Fe-doped MOF precursors. The dense Fe atoms within the nanostructures are dispersed in single-atom level with metalloporphyrin-like Fe–N 4 configuration. The introduction of plentiful large mesopores into the nanoframes would not only enhance the accessibility of abundant single-atom active sites, but also boost mass and charge transports. Such distinctive nanostructure led to exceptional bifunctional electrocatalytic performances for oxygen reduction reaction, with more positive onset potential (1.01 V vs. 0.97 V) and half-wave potential (0.89 V vs. 0.82 V) compared with the commercial Pt/C, and electrochemical carbon dioxide reduction. [ABSTRACT FROM AUTHOR]