Search

[Display omitted] • Robust poly(ionic liquid)@porous carbon nanocomposites were constructed rationally. • Low-concentration CO 2 capture and in-situ conversion have been achieved. • The optimal PIL-Br 1.0 @Zn-CTM exhibits excellent reusability and versatility. • A feasible mechanism for CO 2 capture and in-situ conversion was proposed. The development of advanced materials with dual functionalities for the capture of low-concentration CO 2 and its in-situ conversion into value-added chemicals under mild and green conditions holds significant practical importance. In this study, we present a facile pyrolysis of fluid precursors followed by an in-situ polymerization strategy for preparing poly(ionic liquid)@porous carbon nanocomposites (PIL-Br x @Zn-CTM), which possess multiple active sites including Lewis acidic Zn2+, Lewis basic N, and nucleophilic Br– groups. Subsequently, we investigate their potential application in the efficient capture and conversion of low-concentration CO 2 into cyclic carbonates. The influence of PIL-Br x @Zn-CTM structures and technological conditions on the cycloaddition reaction between low-concentration CO 2 (15 % CO 2 and 85 % N 2) and epichlorohydrin was examined. The PIL-Br 1.0 @Zn-CTM nanocomposite was determined to be the most suitable catalyst, resulting in a 94 % yield of chloropropene carbonate with 99 % selectivity under mild, co-catalyst-, and solvent-free conditions. Furthermore, the reusability of PIL-Br 1.0 @Zn-CTM and its substrate scope were investigated. The PIL-Br 1.0 @Zn-CTM exhibited sustained high activity without a significant decrease after seven cycles of reuse, and it also demonstrated excellent catalytic activity for cycloaddition reactions involving low-concentration CO 2 with various substituted epoxides. Finally, a mechanism for the cycloaddition reaction catalyzed by the PIL-Br x @Zn-CTM nanocomposite was proposed. [ABSTRACT FROM AUTHOR]

Multiple active sites modified THPMOs with regular mesoporous structure exhibit enhanced CO 2 capture and conversion performance under mild and green conditions. [Display omitted] • Robust THPMOs with tunable porosity and multiple active sites are developed. • Optimized THPMO shows excellent dual functions of CO 2 adsorption and conversion. • THPMO promotes CO 2 /epoxide cycloaddition under mild and green conditions. • THPMO is easily recyclable and exhibits good thermal and structural stability. • Synergistic catalytic mechanism of THPMO/TBAI is theoretically evidenced. It is challenging to integrate various active species into porous materials in an organized manner to realize efficient and synchronous CO 2 adsorption and chemical conversion. Here multiple Lewis base and dual hydrogen bond donor (HBD) units were integrated into an organosilicon precursor, and novel triazine and hydrazo sites co-modified periodic mesoporous organosilicas (THPMOs) were prepared via a simple hydrothermal self-assembly method. The morphological structures of THPMOs with different contents of active sites were characterized. The THPMOs displayed high BET surface areas (699–876 m2/g) and favorable low-pressure CO 2 adsorption capacities at 273 K. When combined with tetrabutylammonium iodide (TBAI), they promoted the model cycloaddition of CO 2 and propylene oxide (PO) effectively. By regulating the molar ratios of organosilica precursors, the obtained THPMO-25 catalyzed this reaction and produced a 96 % propylene carbonate (PC) yield under mild conditions. Moreover, the THPMO-25 was applicable using various epoxides and also exhibited satisfactory structural stability during recycling. Combined with theoretical calculations, an insight into the reaction mechanism involving multiple hydrogen-bond interactions was provided. The robust and recyclable nanomaterials offer an attractive approach for CO 2 adsorption and subsequent chemical synthesis of organic carbonate. [ABSTRACT FROM AUTHOR]

Several urea derivative-based ionic liquids (UDILs) with superior thermal stability were facilely synthesized, structurally analyzed, and applied to CO2 capture and conversion under mild conditions. These UDILs reversibly capture CO2 with double molar CO2 absorption and exhibit outstanding catalytic activity for the conversion of CO2 and various epoxides to cyclic carbonates under metal- and solvent-free conditions. The effects of reaction parameters on the catalytic activity for propylene carbonate (PC) synthesis from propylene oxide (PO) and CO2 were thoroughly investigated. Because water is inevitably contained in real gases requiring treatment, the influence of water on CO2 capture and conversion was also studied. Furthermore, reaction kinetic studies were also undertaken and a cation–anion synergistic catalytic mechanism was proposed. The single-component, metal-free, dual functional, stable, and easily recyclable ionic liquids reported herein are interesting materials, displaying a good performance for both CO2 capture and conversion. [ABSTRACT FROM AUTHOR]

Novel ZIF-8(Zn/Co)@g-C 3 N 4 nanocomposites are developed and exhibit superior dual functions for atmospheric CO 2 capture and conversion. [Display omitted] • The study demonstrates a simple method for preparation of advanced nanocomposites. • Robust ZIF-8(Zn/Co)@g-C 3 N 4 nanocomposites with multiple active sites are developed. • The material exhibits superior performance for atmospheric CO 2 capture and conversion. • The optimal ZCN-60 is recyclable and exhibits excellent reusability and versatility. The development of novel catalytic materials that integrate multifunctional sites has significant implications for expanding the utilization of CO 2 resources. However, simultaneously achieving high activity and stability remains a formidable challenge. In this study, a series of ZIF-8(Zn/Co)@g-C 3 N 4 nanocomposites were prepared by employing a thermo-physical compounding strategy that involved the combination of nitrogen-rich graphitic carbon nitride (g-C 3 N 4) nanosheets with ZIF-8(ZnCo). The influences of different compositions of g-C 3 N 4 and ZIF-8(Zn/Co) on the catalyst structure were systematically investigated. Subsequently, the catalytic activities of these nanocomposites towards the cycloaddition reaction between CO 2 and epoxide were examined under different conditions. The presence of abundant Lewis base sites in g-C 3 N 4 facilitates CO 2 activation, while multiple Lewis acid sites in ZIF-8(Zn/Co) enable efficient epoxide activation. By working synergistically with a co-catalyst, tetrabutylammonium bromide (TBAB), CO 2 and epoxides can be efficiently reacted to synthesize the corresponding cyclic carbonates under mild or even atmospheric pressure conditions. The catalytic reaction conditions were optimized, and both the catalyst's recycling performance and the scope of epoxides with various substituents were investigated. The integration of g-C 3 N 4 and ZIF-8(Zn/Co) endows the catalytic material with exceptional structural stability and remarkable catalytic activity, thereby providing a new platform for highly efficient CO 2 conversion. [ABSTRACT FROM AUTHOR]

Bipyridine-derived zwitterionic PMOs with multiple active sites have been developed and demonstrated to exhibit superior performance for flue gas CO 2 capture and in-situ conversion. [Display omitted] • Robust bipyridine-derived zwitterionic organosilicas were constructed rationally. • Low-concentration CO 2 capture and in-situ conversion have been achieved. • The optimal catalyst exhibits excellent reusability and versatility. • In-situ FTIR monitoring assists in elucidating the catalytic mechanism. The development of bi-functional materials for efficient capture and direct in-situ conversion of low-concentration CO 2 from flue gas is both crucial and challenging. In this study, robust bipyridine-derived zwitterionic organosilicas (iPMO x -Bpy-R; R=CH 3 , CH 2 OH, and COOH) were prepared through hydrothermal co-condensation combined with post-quaternization modification strategies. These materials have high specific surface areas (428–585 m2/g) and multiple active sites that include Lewis basic groups, rich hydrogen-bond donors (HBDs), and nucleophilic groups. By precisely controlling the structures of iPMO x -Bpy-R materials, efficient capture and in-situ conversion performance for low-concentration CO 2 from flue gas can be achieved under mild and metal-/solvent-/co-catalyst-free conditions. Notably, when employing the iPMO 25 -Bpy-CH 2 OH catalyst in cycloaddition reaction between CO 2 and propylene oxide at 90 °C under 1 MPa flue gas pressure for 7 h, an impressive propylene carbonate yield of 96 % with a selectivity of 99 % was achieved. Importantly, the iPMO 25 -Bpy-CH 2 OH catalyst maintained its high structural stability and catalytic activity even after six cycles of reuse and also showed excellent versatility towards other substituted epoxides. Finally, a rational mechanism for the cycloaddition reaction between CO 2 and epoxide catalyzed by iPMO 25 -Bpy-CH 2 OH was elucidated based on in-situ FT-IR analyses. [ABSTRACT FROM AUTHOR]

Novel phenylpyridine-based HCPs are facilely prepared and exhibit superior dual functions for atmospheric CO 2 capture and conversion. [Display omitted] • Phenylpyridine-based HCPs with excellent characteristics are facilely prepared. • The HCPs exhibit superior performance for atmospheric CO 2 capture and conversion. • The optimal TPA-HCP-Py catalyst shows good reusability and versatility. • Valuable insight into the cycloaddition mechanism is theoretically elucidated. Several phenylpyridine- and phenyl-based hypercrosslinked polymers (HCPs) were prepared via a one-step Friedel-Crafts polymerization and used as catalysts for the cycloaddition reaction between atmospheric CO 2 and epoxides to produce cyclic carbonates. The structural characteristics and catalytic activity of different HCP catalysts were compared, while the recycling performance and universality to various substituted epoxides were investigated. The as-prepared catalysts exhibited regular pore structure and high specific surface area (1133 m2/g). Under the synergistic effect of tetrabutylammonium iodide (TBAI), the optimized TPA-HCP-Py efficiently converted atmospheric CO 2 into cyclic carbonates with good to excellent product yields. Furthermore, the TPA-HCP-Py catalyst was easy to recover, and no significant changes were observed after reusing for five times, which demonstrated its excellent recycling performance. The interactions between different active sites and reactants in the TPA-HCP-Py/TBAI catalytic system were investigated by DFT calculation, revealing the catalytic reaction mechanism and providing valuable guidance for developing new multifunctional catalysts. [ABSTRACT FROM AUTHOR]

Novel Zn,N co-doped 3D carbon frameworks are developed and exhibit superior dual functions for atmospheric CO 2 capture and conversion. [Display omitted] • In-situ polymerization-pyrolysis strategy is developed for preparation of carbon materials. • Robust Zn,N co-doped 3D carbon frameworks are facilely constructed. • The materials show superior dual functions for atmospheric CO 2 capture and conversion. • The optimal 4%Zn@CTDPOP-IL-700 exhibits excellent recyclability and versatility. Through the rational design of 1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([Bmim][NTf 2 ])-based multi-component fluid precursors, we present a novel and sustainable strategy for preparing Zn,N co-doped 3D carbon frameworks (Zn@CTDPOP-IL) via in-situ polymerization-pyrolysis of fluid precursors, and explore their applications in atmospheric CO 2 capture and clean conversion into cyclic carbonates. The structure and performance of Zn@CTDPOP-IL frameworks were optimized by preparing them under different pyrolysis temperatures and fluid precursor compositions. It was found that the in-situ polymerization of aldehyde and amine components in fluid precursors was crucial for achieving a high specific surface area of carbon frameworks; [Bmim][NTf 2 ] was used as both the solvent and catalyst for in-situ polymerization, as well as the soft template agent during subsequent pyrolysis process. The carbon frameworks also possess multiple Lewis acid/base active sites, exhibiting excellent CO 2 adsorption (3340 μmol/g) and conversion performance under mild (40 °C, 0.1 MPa) and solvent-free conditions. The cyclic carbonate yield reaches up to 94 % with a selectivity of 99 %, which is attributed to the superior activation abilities of Lewis acid/base sites towards epoxide and CO 2 respectively. The reusability and universality of the catalyst were further investigated, revealing its exceptional structural stability and satisfactory versatility. Finally, we elucidated a proposed cycloaddition mechanism catalyzed by multiple active sites in Zn@CTDPOP-IL. Compared to other reported porous carbon materials, the Zn@CTDPOP-IL frameworks developed herein are simple and environmentally friendly in preparation while exhibiting excellent dual functionality for CO 2 adsorption and catalytic conversion, making them highly promising for cleaner treatment of low-pressure waste CO 2 resource. [ABSTRACT FROM AUTHOR]

Robust Zn-TPMO x @PIL-C n hetero-frameworks are developed and exhibit excellent performance for in-situ flue gas CO 2 capture and transformation. [Display omitted] • Robust Zn-TPMO x @PIL-C n hetero-frameworks with multiple active sites are developed. • The catalyst shows excellent dual functions of in-situ CO 2 capture and conversion. • The optimal Zn-TPMO 20 @PIL-C 6 exhibits excellent recyclability and versatility. • A novel strategy is presented for the effective utilization of low-concentration CO 2. Chemical utilization of CO 2 has garnered significant attention in response to the growing environmental and energy challenges. Novel porous hetero-frameworks, Zn-TPMO x @PIL-C n , are developed herein via in-situ polymerization of [VImC n ]Br (n = 2, 4, 6) onto porphyrin derivative-functionalized organosilicas (Zn-TPMO x , x = 10, 15, 20). The structures of Zn-TPMO x @PIL-C n are characterized and found to possess high specific surface area as well as multiple active sites including Lewis acid/base groups, dual hydrogen bond donors and nucleophilic groups. These hetero-frameworks are then utilized for the synthesis of cyclic carbonates through in-situ capture and conversion of CO 2 from simulated flue gas. The catalytic performance of different Zn-TPMO x @PIL-C n and technological conditions are investigated, revealing that the optimal Zn-TPMO 20 @PIL-C 6 catalyst achieves a 96 % yield of chloropropene carbonate with 99 % selectivity under reaction conditions of 110 °C, 1 MPa flue gas for 6 h. Through an assessment of the recyclability and versatility of Zn-TPMO 20 @PIL-C 6 catalyst, it is observed that the robust Zn-TPMO 20 @PIL-C 6 maintains its high activity even after five cycles. Furthermore, this catalyst exhibits satisfactory performance in promoting reactions between various epoxides and flue gas CO 2. Based on the synergistic activation of multiple active sites, the cycloaddition mechanism between CO 2 and epoxide under the catalysis of Zn-TPMO x @PIL-C n is proposed. [ABSTRACT FROM AUTHOR]

Multi-site integrated M⊂PPTFs nanomaterials are developed and show excellent dual functions of CO 2 adsorption and catalytic conversion under mild conditions. [Display omitted] • Multi-site integrated M ⊂ PPTFs nanomaterials with excellent features are constructed. • Optimal Zn ⊂ PPTF 15 shows excellent dual functions of CO 2 adsorption and catalytic conversion. • Zn ⊂ PPTF 15 promotes the CO 2 /epoxide cycloaddition to conduct under ambient pressure. • Zn ⊂ PPTF 15 is easily recyclable and exhibits good thermal and structural stability. The development of multi-site integrated nanomaterials with remarkable properties and their application to selective CO 2 capture and utilization have attracted extensive research interest. In this study, several metalloporphyrin and triazine integrated nitrogen-rich frameworks (M ⊂ PPTFs; where "M" stands for metal) were constructed and structurally characterized. These frameworks' tendency to adsorb CO 2 and their catalytic performance in the conversion of CO 2 to cyclic carbonates were then investigated. The cycloaddition between CO 2 and epichlorohydrin to produce chloropropene carbonate was selected as model reaction to screen the various catalysts and optimize the reaction conditions. The recycling performance and substrate scope were also evaluated. Evidence indicated that Zn ⊂ PPTF 15 has dual functions: CO 2 adsorption and its synergistic conversion. The CO 2 adsorption capacity reached values of 2315 μmol/g and 1883 μmol/g at 273 K and 298 K, respectively. Under conditions of synergistic catalysis with tetrabutylammonium bromide (TBAB), Zn ⊂ PPTF 15 afforded 96% yield of chloropropene carbonate with 99% selectivity at 60 °C and 0.1 MPa CO 2 pressure for 15 h. The catalytic conditions and activity were investigated by comparison with reported triazinyl-based polymers. Notably, the catalytic system also displayed satisfactory applicability to other epoxides. Furthermore, Zn ⊂ PPTF 15 was easily recyclable and did not become deactivated after repeated use. Based on the multi-site structure of the catalyst and the experimental results, a possible mechanism was proposed for the cycloaddition reaction. [ABSTRACT FROM AUTHOR]

Robust ZPOFs with multiple active sites are facilely constructed and show remarkable CO 2 adsorption and conversion performance under mild/green conditions. [Display omitted] • Novel ZPOFs with multiple active sites are prepared via ionothermal polymerization. • The ZPOFs show exciting dual-functions for CO 2 adsorption and conversion. • The ZPOF-mediated CO 2 coupling reaction can proceed under mild/green conditions. • The present ZPOF is easily separated and shows good stability and reusability. • The optimum catalyst exhibits excellent broad substrate scope. Porous organic frameworks fabricated by well-defined monomeric compounds with different active sites have been regarded as the promising nano-materials for improving the efficiency of CO 2 capture and utilization. In this study, novel zwitterionic porous organic frameworks (ZPOFs) alternately connected by benzimidazole, triazine and imidazolium modules were prepared facilely via ZnCl 2 -catalyzed bi-component polymerization. The influences of different monomer concentration and polymerization temperature on structural properties of the ZPOFs were discussed in detail. It indicates that the ZPOFs present attractive structure characteristics of high specific surface area and hierarchical pore structure, and have abundant hydrogen bond donors, Lewis bases and nucleophilic groups, respectively. The ZPOFs as-obtained were applied to CO 2 adsorption and conversion into cyclic carbonate by coupling with epoxide. The experiment results showed that the ZPOFs could afford the highest CO 2 adsorption capacity of 2505 μmol/g at 273 K and 1.0 bar CO 2 pressure. The effects of ZPOFs structures and reactions conditions on the catalytic performance were investigated. Under the optimized conditions of 70 °C, 2.0 MPa CO 2 for 2.0 h, and cooperating with tetrabutylammonium iodide (TBAI) cocatalyst, the ZPOF-450–30 could efficiently and selectively catalyze the CO 2 /epoxides cycloaddition reaction to yield corresponding cyclic carbonates. Moreover, the ZPOF-450–30 catalyst could be simply separated with durable high stability and activity. Finally, we compared the catalytic behaviors with reported similar heterogeneous catalysts and proposed a feasible ZPOFs-catalyzed mechanism. [ABSTRACT FROM AUTHOR]

Microporous carbon xerogels (CXs) were successfully fabricated via a facile one-pot strategy using eutectic salt mixture (KCl and ZnCl 2) as dual activator and catalyst. Their pore structures, morphology, and selective CO 2 adsorption behaviors were thoroughly studied by varying the contents of eutectic salt mixture. The presented CXs herein showed excellent CO 2 adsorption selectivities, and the CX-4 with optimum salt concentration (12.9%) exhibited the highest CO 2 adsorption capacity of 4.39 mmol g−1 at 273 K, which was ascribed to their special microscopic pore structure. Compared with the reported carbon materials, the optimum CX-4 exhibits a comparable or superior CO 2 adsorption performance under similar conditions, showing great potential for efficient CO 2 capture and separation from flue gas and natural gas. [ABSTRACT FROM AUTHOR]