Reaction Of Carbon Dioxide Research Articles

Tuning the Coordination Structure of CuNC Single Atom Catalysts for Simultaneous Electrochemical Reduction of CO2 and NO3– to Urea

AbstractClosing both the carbon and nitrogen loops is a critical venture to support the establishment of the circular, net‐zero carbon economy. Although single atom catalysts (SACs) have gained interest for the electrochemical reduction reactions of both carbon dioxide (CO2RR) and nitrate (NO3RR), the structure–activity relationship for Cu SAC coordination for these reactions remains unclear and should be explored such that a fundamental understanding is developed. To this end, the role of the Cu coordination structure is investigated in dictating the activity and selectivity for the CO2RR and NO3RR. In agreement with the density functional theory calculations, it is revealed that Cu‐N4 sites exhibit higher intrinsic activity toward the CO2RR, whilst both Cu‐N4 and Cu‐N4−x‐Cx sites are active toward the NO3RR. Leveraging these findings, CO2RR and NO3RR are coupled for the formation of urea on Cu SACs, revealing the importance of *COOH binding as a critical parameter determining the catalytic activity for urea production. To the best of the authors’ knowledge, this is the first report employing SACs for electrochemical urea synthesis from CO2RR and NO3RR, which achieves a Faradaic efficiency of 28% for urea production with a current density of −27 mA cm–2 at −0.9 V versus the reversible hydrogen electrode.

Elucidating the Reaction Pathways Responsible for Carbon Monoxide Production in Solid Oxide Co-Electrolysis Cells: A Theoretical Framework

The continuous emission of anthropogenic greenhouse gases, in tandem with the demand for renewable and intermittent energy storage systems, has given rise to the development of technologies which can convert carbon dioxide into useful chemicals and feedstocks. Solid oxide co-electrolysis cells have the potential to help address these demands, as they can efficiently convert carbon dioxide and steam into synthesis gas (carbon monoxide and hydrogen) utilizing clean electricity, which can then be supplied downstream to Fischer-Tropsch reactors in order to produce synthetic liquid fuels. Advantages of solid oxide co-electrolysis cells are mainly attributed to their capacity to operate at high temperatures, which in turn enhances the catalytic performance of electrode materials and reduces the amount of energy required to facilitate the electrochemical reduction of carbon dioxide and steam. The development of these devices has consequently drawn significant attention from designers and researchers, and have emerged as a promising alternative for renewable energy storage and synthesis gas production. One important challenge that has arisen in the analysis of solid oxide co-electrolysis cells is determining the reaction pathways responsible for carbon monoxide production. Studies have suggested that the reverse water gas shift reaction is the primary mechanism [1,2], since the co-electrolysis polarization curves have been shown to be identical to those obtained in pure steam electrolysis, while others have found that such curves lie between the results produced by pure steam and pure carbon dioxide electrolysis, thus indicating the electrochemical reduction of carbon dioxide and reverse water gas shift reaction are both contributors [3,4]. Given the varying operating conditions and cell designs that have been implemented in these studies, it is difficult to draw meaningful comparisons between these results and to deduce the reaction pathways by which carbon monoxide is generated. The objective of the current work is to, therefore, develop a theoretical framework to elucidate the reaction pathways which govern carbon monoxide production for a broad range of operating conditions and design specifications. An in-house 1-Plus-1D transport model is developed to quantify how each transport mechanism affects the rate of production and consumption of carbon monoxide, as well as the operating potential of a solid oxide co-electrolysis cell. This analysis is intended to cultivate an improved understanding of the reaction pathways responsible for carbon monoxide production and to reveal how they can be exploited in order to enhance the performance of solid oxide co-electrolysis cells.[1] P. Kim-Lohsoontorn and J. Bae, J. Power Sources, 196, 7161 (2011).[2] C. Stoots, J. O’Brien and J. Hartvigsen, Int. J. Hydrogen Energy, 34, 4208 (2009).[3] C. Graves, S. D. Ebbesen and M. Mogensen, Solid State Ion., 192, 398 (2011).[4] W. Li, H. Wang, Y. Shi and N. Cai, Int. J. Hydrogen Energy, 38, 11104 (2013).

In Situ Copper Nanoparticles on Reduced Graphene Oxide (rGO/Cu) for Biphasic Hydrogen Evolution

AbstractGraphene‐based nanocomposites have attracted a tremendous attention, showing excellent performance in energy conversion applications, such as reduction of carbon dioxide and hydrogen evolution reaction (HER). Herein, a study on in situ generation Cu nanoparticles on reduced graphene oxide (rGO/Cu) by reducing simultaneously both graphene oxide and Cu2+ ions during the biphasic HER by organic sacrificial agent decamethylferrocene (DMFc) was reported. The in situ‐generated rGO/Cu catalyst was morphologically and structurally characterized by microscopic and spectroscopic techniques, respectively. The hydrogen evolution catalytic activity of rGO/Cu was investigated by using 4‐electrode voltammetry and two‐phase reaction methods. rGO/Cu nanocomposite catalyst displayed a better catalytic activity than the non‐catalyzed reaction and free‐Cu catalyst by enhancing the HER rate approximately 208‐ and 3‐times, respectively. The HER activity of rGO/Cu gave results comparable to the noble metallic and the other nanocomposite catalysts such as Pt, Pd, MoSx and their nanocomposites with carbon‐based materials.

CO2 and ethylene epoxide on silicon-doped CNT as metal-free catalyst to produce cyclic ethylene carbonate: a computational study

Cyclic ethylene carbonate is an essential compound in the industry with many uses. This compound can be produced by reaction of carbon dioxide as a greenhouse gas and ethylene epoxide. A toxic and expensive metal as a catalyst is mostly used for this reaction. So, introducing an inexpensive and metal-free catalyst for this reaction may be helpful. For this aim, we studied the carbon nanotube with the characteristic properties. The surface activity of the carbon nanotube was improved by substituting one carbon atom with a silicon atom for this reaction. In this work, we studied two possible reaction pathways for the reaction of carbon dioxide and ethylene epoxide on the surface of a silicon-doped carbon nanotube. We studied about the electrostatic potential surfaces to predict possible interactions and surface activity. Also, the thermodynamic parameters have been calculated for these processes. The calculated thermodynamic parameters show that the adsorption of these molecules on the silicon-doped carbon nanotube is exothermic, and the next steps of the reaction pathways are thermodynamically favoured.

Efficient synthesis of cyclic carbonates under atmospheric CO2 by DMAP-based ionic liquids: the difference of inert hydrogen atom and active hydrogen atom in cation

The coupling reaction of carbon dioxide (CO2) and epoxides is one of the most efficient pathways to achieve the carbon balance. However, to accomplish it under the mild conditions, especially under the atmospheric pressure, is still a perplexing problem. Three novel ionic liquids (ILs), [DMAPBrPC][TMGH], [DMAPBrPC][DBUH], and [DMAPBrPC][BTMA], are designed and synthesized. All of them display the excellent catalytic activity for the title reaction achieving the yield over 96.6% under the atmospheric CO2 pressure at 60 °C. Interestingly, [DMAPBrPC][BTMA] with the inert hydrogen atom in cation exhibits the superior catalytic activity as compared to other two ILs with the protic hydrogen atom in cation along with the same anion. The active hydrogen atom in [DMAPBrPC][TMGH] and [DMAPBrPC][DBUH] would impede the –COO− group to absorb CO2, which is an unfavorable item for the reaction. Moreover, the strong hydrogen bond in [DMAPBrPC][TMGH] and [DMAPBrPC][DBUH] would lessen the nucleophilic ability of Br− anion resulting in the inferior catalytic performance, which is further confirmed by the density functional theory (DFT) calculations. The cation without the active hydrogen atom could also be employed to design the ILs with the excellent catalytic feature when it is combined with the suitable anion.

Mineral carbonation of ultramafic tailings: A review of reaction mechanisms and kinetics, industry case studies, and modelling

Reduction of greenhouse gas emissions is becoming a greater priority in the mining industry due to increasing social pressures, government incentives, and its consideration in companies stock evaluation. Carbon capture and sequestration in ultramafic tailings (mineral carbonation) is one technology companies can use to offset their carbon emissions. Mineral carbonation refers to the spontaneous reaction of carbon dioxide with divalent metal minerals, which safely and permanently stores carbon dioxide as a carbonate sediment. Carbon sequestration can occur passively in ultramafic mine tailings storage facilities or under optimized conditions in process designs. This review discusses the literature on mineral carbonation reaction mechanisms, candidate minerals, kinetic parameters, potential methods to accelerate mineral carbonation, examples of industry mineral carbonation, and mine-scale mineral carbonation modelling. • Mineral carbonation reaction rate limiting mechanisms and thermoynamics. • Effect of water saturation, temperature, mineralogy, depth, pH, CO 2 and grain size. • Technologies to improve CO 2 sequestration in ultramafic tailings. • Reactive transport modelling of mineral carbonation in ultramafic tailings.

Critical Study on Corrosion Inhibitors in U-Shaped RCC Beams

In most structural failures, deterioration of reinforced concrete structure is due to corrosion of reinforcing bars. Ingress of chloride ions and reaction of carbon dioxide with the cement paste due to poor-quality concrete or inadequate cover are the main causes of corrosion. Corrosion can be reduced by using high-quality concrete and providing proper cover to reinforcement. In addition, corrosion inhibitors are used to protect the reinforcement in order to extend the service life of concrete structures. This research work is focused on determining the effectiveness of corrosion inhibitors under cracked and uncracked sections of U-shaped beam. The U-shaped beam concept was used in this study, which helps to develop the crack width within 0.3 mm as per IS: 456 code provision. The two vertical stubs of the U-shaped beam were stressed in order to generate the cracks at the soffit of the beam. Then, the beams are tested for accelerated corrosion along with the half-cell potential meter calculations for the corrosion potential measurement.

Cycloaddition of allylic chlorides, aryl alkynes, and carbon dioxide using nanoclusters of polyoxomolybdate buckyball supported by ionic liquid on dendritic fibrous nanosilica

Due to the uncontrolled emissions of CO2 created by industrial procedures that lead to acidification of the oceans and universal warming, various methods have been utilized for direct absorption of CO2 from waste water sources. The generation of green nano catalyst with chemical adjustments to be converted to value-added products can be considered alluring. Therefore, we synthesized Polyoxomolybdate [Mo132] nanoball with different alkyl groups loaded on dendritic fibrous nanosilica by ionic liquid (DFNS/IL/Mo132) using an easy synthetic route. Owing to the DFNS/IL/Mo132 morphology, a suitable external level for CO2 uptake was generated at all Mo132 sites. Results revealed that DFNS/IL/Mo132 positively influenced the preparation efficiency of 3a,4-dihydronaphtho[2,3-c]furan-1(3H)-one through a three-element binding reaction of alkynes, allylic chlorides, and carbon dioxide. This approach is beneficial in terms of profitable efficacy and forbearance of functional groups.

Gold-Aluminyl and Gold-Diarylboryl Complexes: Bonding and Reactivity with Carbon Dioxide.

The unconventional carbon dioxide insertion reaction of a gold-aluminyl [tBu3PAuAl(NON)] complex has been recently shown to be related to the electron-sharing character of the Au–Al bond that acts as a nucleophile and stabilizes the insertion product through a radical-like behavior. Since a gold-diarylboryl [IPrAuB(o-tol)2] complex with similar reactivity features has been recently reported, in this work we computationally investigate the reaction of carbon dioxide with [LAuX] (L = phosphine, N-heterocyclic carbene (NHC); X = Al(NON), B(o-tol)2) complexes to get insights into the Al/B anionic and gold ancillary ligand effects on the Au–Al/B bond nature, electronic structure, and reactivity of these compounds. We demonstrate that the Au–Al and Au–B bonds possess a similar electron-sharing nature, with diarylboryl complexes displaying a slightly more polarized bond as Au(δ+)–B(δ–). This feature reduces the radical-like reactivity toward CO2, and the Al/B anionic ligand effect is found to favor aluminyls over boryls, despite the greater oxophilicity of B. Remarkably, the ancillary ligand of gold has a negligible electronic trans effect on the Au–X bond and only a minor impact on the formation of the insertion product, which is slightly more stable with carbene ligands. Surprisingly, we find that the modification of the steric hindrance at the carbene site may exert a sizable control over the reaction, with more sterically hindered ligands thermodynamically disfavoring the formation of the CO2 insertion product.

Modulating electric field distribution by alkali cations for CO2 electroreduction in strongly acidic medium

The reaction of carbon dioxide with hydroxide to form carbonate in near-neutral or alkaline medium severely limits the energy and carbon efficiency of CO2 electroreduction. Here we show that by suppression of the otherwise predominant hydrogen evolution using alkali cations, efficient CO2 electroreduction can be conducted in acidic medium, overcoming the carbonate problem. The cation effects are general for three typical catalysts including carbon-supported tin oxide, gold and copper, leading to Faradaic efficiency as high as 90% for formic acid and CO formation. Our analysis suggests that hydrated alkali cations physisorbed on the cathode modify the distribution of electric field in the double layer, which impedes hydrogen evolution by suppression of migration of hydronium ions while at the same time promoting CO2 reduction by stabilization of key intermediates.

Exploration of catalytic species for highly efficient preparation of quinazoline-2,4(1H,3H)-diones by succinimide-based ionic liquids under atmospheric pressure: Combination of experimental and theoretical study

Cyclization reaction of carbon dioxide (CO2) and 2-aminobenzonitriles is of significance for the sustainable development, however, the harsh reaction condition especially for the high CO2 pressure is still an obstacle. Herein, a novel ionic liquid benzyltrimethylammonium succinimide ([BzTMA+][Suc−]) is designed and synthesized, in which no active hydrogen atom is included in cation. It displays the excellent catalytic activity achieving the 98.8% yield for quinazoline-2,4(1H,3H)-diones even under the atmospheric pressure. By combination of nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR), CO2 absorption measurements, densityfunctionaltheory (DFT) calculations, and the frontier molecular orbital analysis, the real catalytic species and synergistic effect of cation and anion on the catalytic performance are elucidated. The [Suc−] anion affords to introduce the CO2 into the organic phase even under the atmospheric pressure by formation of [Suc-CO2−]. However, the real catalytic species is [BzTMA+] cation and [Suc−] anion rather than [BzTMA+] and [Suc-CO2−]. If the active hydrogen atom is included in the cation, the CO2 absorption capacity of [Suc−] anion would be weakened by the strong interaction between active hydrogen atom in cation and [Suc−] anion resulting in the inferior catalytic behavior. The cooperation of [BzTMA+] and [Suc−] finally results in the high catalytic activity under the atmospheric pressure. Involvement of active hydrogen atom in cation is not an insurance to prepare the robust catalyst.

Organic frameworks confined Cu single atoms and nanoclusters for tandem electrocatalytic CO2 reduction to methane

AbstractThe electrochemical reduction reaction of carbon dioxide (CO2RR) is considered to be an effective way to realize carbon neutrality. As a type of intensively studied materials, covalent organic frameworks (COFs) with a tunable pore structure and various functional groups are promising catalysts for CO2RR. Herein, COF synthesized by 2,6‐diaminoanthraquinone and 2,4,6‐triformylphloroglucinol is employed to assist the synthesis of electrocatalysts from Cu single atoms (SAs) to nanoclusters by controlling the electrodeposition. A tandem catalyst for CO2‐to‐CH4 conversion is thus achieved by the Cu nanoclusters dispersed among the isolated Cu SAs in the COF network. It is proposed that CO2 is first reduced to CO over the atomically isolated Cu SAs, followed by diffusion onto the neighboring Cu nanoclusters for further reduction into CH4. In addition, mechanistic analysis suggests that the coordinated K+ ions on the COF network promote the activation of CO2 and the adsorption of reaction intermediates, thus realizing the suppressed hydrogen evolution reaction and selective production of CH4. This study presents a new insight of COFs for the confined synthesis of a tunable SA to nanocluster electrocatalysts, disclosing the great potential of COFs in electrocatalysis.

Design and synthesis of pyridinamide functionalized ionic liquids for efficient conversion of carbon dioxide into cyclic carbonates

Novel and facilely prepared 2-pyridinamide-functionalized ionic liquids 1–4 (PAIL1–4) were explored for the cycloaddition reaction of carbon dioxide with various epoxides to generate cyclic carbonates. The optimum temperature, CO2 pressure, and catalyst dosage of the cycloaddition reaction, are 60 °C, 0.5 MPa, and 5 mol% respectively. The synthesized N, N-dimethyl-N-(2-oxo-2-(pyridin-2-ylamino)ethyl)butan-1-aminium iodide (PAIL-3) exhibited brilliant catalytic activities under mild conditions with nearly quantitative selectivity and conversion in the absence of any solvents, or metal co-catalysts. The catalyst PAIL-3 could be recycled 4 times without obvious loss of its catalytic activity. Moreover, a plausible mechanism is proposed based on the NMR experiments. The designed pyridinamide functionalized ionic liquids integrated pyridine unit, halogen anion and the N-H moiety in amide and they have an excellent synergistic catalytic effect in promoting the coupling reactions of carbon dioxide and epoxides.

Porous polymeric metalloporphyrin obtained through Sonogashira coupling: Catalytic performance at CO2 cycloaddition to epoxides

Using metal complexes of (5,10,15,20-tetrakis(p-bromophenyl) porphyrin) (MT4BrPP) (M ​= ​Co, Mn) and 4,4-diethynylbiphenyl as monomers, a porous polymeric metalloporphyrin [PoP(MTPP), M ​= ​Co, Mn] was successfully synthesized by Sonogashira cross-coupling reaction. Their morphology, structure and elements were characterized and analyzed by scanning electron microscopy (SEM), Fourier-Transform infrared spectroscopy (FT-IR), X-ray photoelectron spectra (XPS), thermogravimetric analysis (TG), and brunauer-emmett-teller (BET), which indicated high specific surface area and good thermal stability. Then, using PoP(MTPP) as porous catalyst with two-dimensional structure, the cycloaddition reaction of epoxides and carbon dioxide (CO2), for reducing greenhouse gas emissions, was effectively executed without solvents, and the yield of cyclocarbonate got to 90%. In summary, a novel metalloporphyrin based porous polymers were prepared by coupling reaction, and catalytic active centers were effectively fixed in two-dimensional networks, which improved its stability and excellently enhanced their catalytic performance. It’s a competitively candidates for catalyzing the cycloaddition reaction without solvent.

Uniform Core-Shell Microspheres of SiO2@MOF for CO2 Cycloaddition Reactions.

A SiO2@MOF core-shell microsphere for environmentally friendly applications was introduced in this study. Several types of metal-organic framework core-shell microspheres were successfully synthesized. To achieve high stability and favorable catalytic performance, modification and coating methods were necessary for optimization. The improved SiO2@MOF core-shell microspheres were used in the cycloaddition reaction of carbon dioxide and propylene oxide. Dispersion ability was enhanced by the addition of core-shell microspheres, which also produced high catalytic activity. Accompanied with tetrabutylammonium bromide as a co-catalyst, SiO2@ZIF-67 had a maximum conversion of 97%, and the results revealed that SiO2@ZIF-67 could be used for 5 reaction cycles while maintaining high catalytic performance. This recycling catalyst was also reacted with a series of terminal epoxides to form corresponding cyclic carbonates with high conversion rates, indicating that SiO2@MOF core-shell microspheres exhibit promise in the field of catalysis.

Two-Dimensional Conjugated Metal-Organic Frameworks for Electrocatalysis: Opportunities and Challenges.

A highly effective electrocatalyst is the central component of advanced electrochemical energy conversion. Recently, two-dimensional conjugated metal-organic frameworks (2D c-MOFs) have emerged as a class of promising electrocatalysts because of their advantages including 2D layered structure with high in-plane conjugation, intrinsic electrical conductivity, permanent pores, large surface area, chemical stability, and structural diversity. In this Review, we summarize the recent advances of 2D c-MOF electrocatalysts for electrochemical energy conversion. First, we introduce the chemical design principles and synthetic strategies of the reported 2D c-MOFs, as well as the functional design for the electrocatalysis. Subsequently, we present the representative 2D c-MOF electrocatalysts in various electrochemical reactions, such as hydrogen/oxygen evolution, and reduction reactions of oxygen, carbon dioxide, and nitrogen. We highlight the strategies for the structural design and property tuning of 2D c-MOF electrocatalysts to boost the catalytic performance, and we offer our perspectives in regard to the challenges to be overcome.

Influence of the gas model on the boundary layer characteristic parameters and transition prediction for the Mars entry capsule

<p indent="0mm">Turbulent transition is an important factor affecting the thermal environment of spacecraft. A boundary layer transition prediction method was developed for both smooth and rough thermal protection system surfaces of a large-scale entry capsule in the process of entering the Martian atmosphere. The effects of the gas model and wall temperature constraints on the boundary layer characteristic parameters and transition features were analyzed. The results indicate that the dissociation reaction of carbon dioxide and its thermodynamic non-equilibrium effect will lead to increases in the momentum thickness Reynolds number and the roughness-height-based Reynolds number of the boundary layer. The radiative-equilibrium wall temperature constraint also results in a higher momentum thickness Reynolds number and roughness-height-based Reynolds number compared to those of the cold wall conditions. Therefore, the thermochemical non-equilibrium and radiative-equilibrium wall temperature boundary condition should be included in the analysis model to obtain the actual transition features.

Synthesis of nucleoside-substituted carbonate and diol derivatives through the carbon dioxide reaction using polyionic liquid catalysts

Under the combined action of water and polyionic liquids, nucleoside drug intermediates was synthesized through CO2 conversion.

The reduction reaction of carbon dioxide on a precise number of Fe atoms anchored on two-dimensional biphenylene.

In recent accomplishments, a new two-dimensional allotrope of carbon-biphenylene (BP) was experimentally synthesized [Fan et al., Science, 372, 852-856 (2021)]. The BP sheet is composed of four-, six-, and eight-membered carbon rings constructed using periodically arranged sp2-hybridized carbon atoms. Unlike semi-metallic graphene, BP is metallic with quite active atoms and chemical bonds, and the binding strength with reaction intermediates will be enhanced, which means that it may exhibit good catalytic activity in some electrochemical catalytic reactions. Using spin-polarized density functional theory based on first-principles simulations and ab initio molecular dynamic calculations, we systematically investigated the structure, thermodynamic stability, CO2 reduction reaction (CO2RR) activity and product selectivity of a precise number of Fen (n = 1-3) atoms embedded on a BP monolayer. The calculated results indicate that our designed Fe1@BP, Fe2@BP and Fe3@BP complexes possess good thermodynamic and electrochemical stabilities and strong absorption for CO2, which promotes the activation of CO2. Furthermore, the Fe2@BP catalyst possesses good catalytic ability for the CO2RR to CH3OH due to a small rate determining potential of -0.48 V. In addition, Fe2- and Fe3@BP catalysts demonstrate superior catalytic performance for the CO2RR to CH4 with low rate-limiting steps. More importantly, both the Fe2 and Fe3@BP catalysts can effectively suppress the hydrogen evolution reaction (HER) during the entire CO2RR process. The electronic structure analysis shows that the enhanced ability of Fe1-3@BP catalysts for effective CO2 reduction can be attributed to the establishment of strong hybridization between Fe-3d and O-2p or C-2p states, which is conducive to the transfer of strong electrons to the anti-bond orbital of CO2. This work provides an in-depth insight into the intrinsic catalytic mechanisms of the CO2RR on Fe1-3@BP catalysts, and highlights the excellent performance of the BP sheet as a substrate material for the polyatomic catalyst.

The Effect of Durability and Corrosion Behavior on the Concrete Treated with Chemical Inhibitor

Chloride-induced corrosion of steel reinforcement and the reaction of atmospheric carbon dioxide with cement paste are the most important causes of premature failure in marine-reinforced concrete structures. Among the available methods, corrosion inhibitors offer a simple and costeffective technique in reducing the chloride-induced corrosion on the steel reinforced concrete.