Reaction Of CO Research Articles

Heteroatom-doped M-N4-C Single-atom catalysts towards electrochemical reactions of CO2: A machine learning-assisted DFT study

Heteroatom-doped M-N4-C Single-atom catalysts towards electrochemical reactions of CO2: A machine learning-assisted DFT study

Pure CO2 and impure CO2-SO2-NO-O2 reactions with carbon storage site underlying seals: Coaly mudstones and carbonate cemented sandstones.

The transition to net zero emissions requires the capture of carbon dioxide from industrial point sources, and direct air capture (DAC) from the atmosphere for geological storage. Dissolved CO2 has reactivity to rock core, and while the majority of previous studies have concentrated on reservoir rock or cap-rock reactivity, the underlying seal formation may also react with CO2. Drill core from the underlying seal of a target CO2 storage site was reacted at in situ conditions with pure CO2, and compared with an impure CO2 stream with SO2, NO and O2 that could be expected from hard to abate industries. Argillaceous sandstones, mudstones, coaly mudstones, and carbonate cemented sandstones of the Moolayember Formation, Bowen Basin, had significant natural alteration of feldspar to kaolinite creating porosity, with clays, siderite and textured ankerite filling and rimming porosities of 3.5 to 15.8%. Synchrotron XFM quantified Mn mainly hosted in siderite veins and cements, Sr and Rb in feldspar, and Pb, Th and Sr in monazite. Pb was also in siderite; with As mainly in pyrite and associated with ankerite. On pure CO2 or impure CO2 reaction, ankerite and siderite dissolution, Fe-chlorite leaching, and apatite or sulphide alteration occurred. With the impure CO2 stream Fe-oxides precipitated on rock surfaces especially in argillaceous sandstone. Ferroan carbonates, calcite, and Fe oxides containing Cr were also precipitated. Ankerite and siderite dissolution released increasing concentrations of dissolved Ca, Mg and Mn from carbonate cemented core that were higher with mixed gas injection. Argillaceous sandstone however released higher concentrations Si, Rb, Co and Zn. Dissolved Fe initially increased then decreased in impure gas experiments via Fe oxide precipitation, and Pb, Ni, Cr, REE also increased and subsequently decreased. Geochemical modelling predicted that Fe was mobilised mainly from reaction of siderite and Fe chlorite. Mainly carbonates (siderite, ankerite) and chlorite dissolution released trace metals, with several metals also initially mobilised by desorption and exchange. Precipitated Fe oxides provided adsorption sites to adsorb a portion of metals from solution. These reactions are also relevant to CO2 streams from DAC that could be expected to contain O2 and to potential reactions in overlying aquifers.

Catalytic Performance of B-Site Doped LST Modified NiO/YSZ Cathodes for CO2 Reduction in a Solid Oxide Electrolyzer

Abstract The NiO/YSZ modified with B-site doped lanthanum strontium titanate (LST) was investigated as cathode materials for the reduction of CO2 in a solid oxide electrolysis cell (SOEC). The electrocatalytic activity evaluated in CO2/H2 under solid oxide fuel cell and SOEC conditions both demonstrated that the cobalt-doped LST (LSTC) performs better than pristine NiO/YSZ and is the best among the doped LSTs. The high performance of the LSTC-modified cathode was ascribed to its good CO2 reduction ability, as evidenced by infrared and temperature-programmed surface reaction studies. Furthermore, LSTC was believed to play a role not only in serving active sites for the CO2 reaction, but also in relieving stress induced by Ni oxidation, thus stabilizing the cathode structure. Direct electrolysis in the absence of H2 further confirmed that the LSTC modified cell exhibits better performance. On the contrary, the other LST-modified cells and a CaO-modified one suffered from severe electrode polarization. These results present the potential to construct a cell combining B-site doped LST oxides with Ni cermet in a SOEC for energy conversion.

Reactivity of Wet scCO2 toward Reservoir and Caprock Formations under Elevated Pressure and Temperature Conditions: Implications for CCS and CO2-Based Geothermal Energy Extraction.

Carbon capture and storage (CCS) and CO2-based geothermal energy are promising technologies for reducing CO2 emissions and mitigating climate change. Safe implementation of these technologies requires an understanding of how CO2 interacts with fluids and rocks at depth, particularly under elevated pressure and temperature. While CO2-bearing aqueous solutions in geological reservoirs have been extensively studied, the chemical behavior of water-bearing supercritical CO2 remains largely overlooked by academics and practitioners alike. We address this knowledge gap by conducting core-scale laboratory experiments, focusing on the chemical reactivity of water-bearing supercritical CO2 (wet scCO2) with reservoir and caprock lithologies and simulating deep reservoir conditions (35 MPa, 150 °C). Employing a suite of high-resolution analytical techniques, we characterize the evolution of morphological and compositional properties, shedding light on the ion transport and mineral dissolution processes, caused by both the aqueous and nonaqueous phases. Our results show that fluid-mineral interactions involving wet scCO2 are significantly less severe than those caused by equivalent CO2-bearing aqueous solutions. Nonetheless, our experiments reveal that wet scCO2 can induce mineral dissolution reactions upon contact with dolomite. This dissolution appears limited, incongruent, and self-sealing, characterized by preferential leaching of calcium over magnesium ions, leading to supersaturation of the scCO2 phase and reprecipitation of secondary carbonates. The markedly differing quantities of Ca2+ and Mg2+ ions transported by wet scCO2 streams provide clear evidence of the nonstoichiometric dissolution of dolomite. More importantly, this finding represents the first reported observation of ion transport processes driven by water continuously dissolved in the scCO2 phase, which challenges prevailing views on the chemical reactivity of this fluid and highlights the need for further investigation. A comprehensive understanding of the chemical behavior of CO2-rich supercritical fluids is critical for ensuring the feasibility and security of deep geological CO2 storage and CO2-based geothermal energy.

Preparation of CuO–CeO2/CaO Composite Oxides and its Ablation Performances of CO/CO2

ABSTRACT CuO – CeO2/CaO composite oxide was prepared for mine special environment in this study through the solid-phase impregnation method using the traditional CuO – CeO2 and CaO as the CO catalyst and the modified additive, respectively, to address the CO poisoning in underground coal mines effectively. Influences of CaO mass on the ablation performances of CuO – CeO2/CaO were investigated under dynamic and static CO/CO2 heat capture experiments using the self-made activity testing device. Results demonstrated that adding CaO can realize in-situ adsorption of CO2, thus increasing utilization of oxygen and promoting CO catalysis of the prepared composite oxide. The performances of CuO – CeO2/0.15CaO was the best when the dosage of CaO was 15 wt%. The CO reaction capacity and CO2 adsorption capacity reached 1.17 and 0.56 mg·g−1, respectively. The thermodynamic properties and microstructural characteristics of the synthesized composite oxide were systematically investigated utilizing a simultaneous thermal analyzer, Fourier infrared spectrometer, XRD diffractometer, and scanning electron microscope. Adding CaO can also improve the thermostability of the composite oxide and increase active sites on the sample surface. The emergence of adsorption products Ca(OH)2 and CaCO3 proves that CuO – CeO2/CaO has relatively good moisture and CO2 adsorption. Analysis of the ablation performances of CO/CO2 after coal combustion with CuO – CeO2/CaO revealed that the prepared composite oxide not only effectively lowers CO concentration after coal combustion but also adsorbs CO2 during catalysis and decreases smoke risks. The released CO concentration from coal combustion after 240 s can be decreased to less than 0.0024% when the mass ratio of CuO – CeO2/0.15CaO and coal is 1:3. The ablation results confirm that, as a new type of composite material, the CuO – CeO2/0.15CaO composite oxide can provide a new technical means for CO control in coal mines.

Retraction: Visible-light driven reaction of CO2 with alcohols using a Ag/CeO2 nanocomposite: first photochemical synthesis of linear carbonates under mild conditions.

Retraction of 'Visible-light driven reaction of CO2 with alcohols using a Ag/CeO2 nanocomposite: first photochemical synthesis of linear carbonates under mild conditions' by Anil Malik et al., Chem. Commun., 2023, 59, 1313-1316, https://doi.org/10.1039/D2CC05152D.

Effects of Mixed Metal Oxide Catalysts on the Synthesis of Cyclic Carbonates from Epoxides under Atmospheric CO2 Pressure.

One use of CO2 as a starting material in organic transformations is in the synthesis of cyclic carbonates and polycarbonates. Due to the low reactivity of CO2, this transformation must be carried out in the presence of an efficient catalyst. Although several catalytic systems have been developed in the past decade, reducing the CO2 pressure at which the reaction is carried out remains one of the main challenges of the process. In this context, in the present work, we describe the catalytic activity of mixed metal oxides in the synthesis of cyclic carbonates from CO2 (1 atm) and epoxides at 70 °C. Using these materials as catalysts represents significant benefits since they are very stable, cost-effective, and can be reused in several reaction cycles.

Nitrite Reduction with H2S/Thiol Mediated by Cobalt and Manganese Porphyrins in the Solid State.

The endogenous reduction of nitrite to nitrosyl is drawing increasing attention as a protective mechanism against hypoxic injury in mammalian physiology and as an alternative source of NO, which is involved in a wide variety of biological activities. Thus, chemical mechanisms for this transformation, which are mediated by metallo proteins, are of considerable interest. The study described here examines the reactions of the biomimetic models Co(TTP)(NO2) (TTP = meso-tetratolylporphyrinato dianion) and Mn(TPP)(ONO) (TPP = meso-tetraphenyl-porphyrinato dianion) in sublimated solid films with hydrogen sulfide (H2S) and with ethanethiol (EtSH) at various temperatures from 77 K to room temperature using in situ infrared and optical spectroscopy. In both cases, the coordinated nitrite complex is eventually converted to the respective nitrosyl Co(TTP)(NO) and Mn(TPP)(NO); however, reaction at low temperature first gave a novel six-coordinate complex M(Por)(RSH)(nitrite). Warming these films in the presence of excess thiol resulted in the formation of the two nitrosyl complexes. Mass spectrometric analysis of volatile products and DFT computations of possible intermediates are reported, and potential mechanisms for reduction of the coordinated nitrite ions are discussed.

Synthesis, crystal structure and properties of catena-poly[[bis-(4-methyl-pyridine-κN)cobalt(II)]-di-μ-thio-cyanato-κ2 N:S;κ2 S:N], which shows a rare coordination geometry.

Reaction of Co(NCS)2 with 4-methyl-pyridine in water leads to the formation of single crystals of the title compound, [Co(NCS)2(C6H7N)2] n . The asymmetric unit consists of two crystallographically independent thio-cyanate anions and two crystallographically independent 4-methyl-pyridine coligands in general positions, as well as of two different CoII cations, of which one is located on a twofold rotational axis, whereas the second occupies a center of inversion. The methyl H atoms in both 4-methyl-pyridine ligands are disordered and were refined using a split model. Both CoII cations are octa-hedrally coordinated by two N- and two S-bonded thio-cyanate anions and two 4-methyl-pyridine coligands and are linked by pairs of 1,3-bridging anionic ligands into chains. Within these chains the cations show an alternating all-trans and cis-cis-trans configuration, which leads to the formation of corrugated chains. Powder X-ray diffraction proves that a pure crystalline phase has been obtained and the values of the CN stretching vibrations of the anionic ligands observed in the IR and the Raman spectra are in agreement with the presence of bridging anionic ligands.

CoII-organic 'soft' metallo-supramolecular polymer nanofibers for efficient photoreduction of CO2.

Coordination-driven metallo-supramolecular polymers hold significant potential as highly efficient catalysts for photocatalytic CO2 reduction, owing to the covalent integration of the light harvesting unit, catalytic center and intrinsic hierarchical nanostructures. In this study, we present the synthesis, characterization, and gelation behaviour of a novel low molecular weight gelator (LMWG) integrating a benzo[1,2-b:4,5-b']dithiophene core with terpyridine (TPY) units via alkyl amide chains (TPY-BDT). The two TPY ends of the TPY-BDT unit efficiently chelate with metal ions, enabling the formation of a metallo-supramolecular polymer that brings together the catalytic center and a photosensitizer in close proximity, maximizing catalytic efficiency for CO2 reduction. The self-assembly of TPY-BDT with CoII ions yields a Co-TPY-BDT coordination polymer gel (CPG) with a 3D interconnected fibrous morphology, facilitating rapid electron transfer and efficient substrate diffusion. The Co-TPY-BDT CPG achieves an outstanding CO2 to CO conversion, producing 33.74 mmol g-1 of CO in 18 hours with ∼99% selectivity under visible light irradiation, using triethylamine (TEA) as a sacrificial electron donor. Remarkably, the Co-TPY-BDT CPG demonstrates significant catalytic activity even under low-concentration CO2 atmospheres (5% CO2, 95% Ar), producing 1.9 mmol g-1 of CO in 10 hours with a selectivity of 94.6%. Moreover, In situ diffuse reflectance Fourier transform (DRIFT) study, femtosecond transient absorption spectroscopy, and DFT calculations were employed to elucidate the CO2 to CO reaction mechanism.

Metal mobilisation and fines migration in pure CO2 and impure CO2-SO2-NO reactions of carbon storage site core.

Carbon dioxide geological storage is proposed as part of the solution to reach net zero emissions. The potential to mobilise heavy metals to low salinity groundwater through CO2 water rock geochemical reactions is a potential environmental risk factor, if CO2 migrates. Previous studies have focused on pure CO2 reactivity, however CO2 streams from hard to abate industries can contain gas impurities. Reservoir sandstone and mudstone drill cores from a proposed low salinity CO2 storage demonstration site were reacted at in situ conditions with pure CO2 or an impure NO-SO2-CO2 stream. Sandstones hosted Rb in illite analysed via synchrotron XFM. Arsenic (As) was hosted in pyrite; and Pb, Cr, Mn in siderite rimming intergranular pores. Mudstone contained Zn, Co, Ni, Cu, As, Pb in sphalerite, and Rb in illite and K-feldspar. In impure NO-SO2-CO2 experiments the lowered pH and oxidising conditions initially released higher concentrations of metals including Pb, Zn, Co into solution compared to pure CO2 reactions. Higher concentrations of Zn (Mn and Co) were released from sphalerite in the mudstone. Fe-chlorite, K-feldspar, and carbonate dissolution released Rb, Si, Fe, Ca, and Mg. Elevated dissolved Pb was mainly from siderite and sulphide mineral reaction in sandstones. Mobilised As was released prior to CO2 addition from desorption and ion exchange. Clay and fines migration into pores occurred in both pure and impure CO2 reactions that has the potential to impact fluid migration. A portion of metals including Fe, Ni, Cr were subsequently incorporated in precipitated Fe hydr(oxy)oxides where the co-injected NO induced oxidising conditions. Rock mineral content and the injected gas mix were the main controls on metal mobilisation to formation water. Further work should investigate new gas mixtures that may be expected in storage hubs, from blue hydrogen or from direct air capture.

Hydrophobic driving fabrication of highly dispersed PtNi in Zr-doped 3D hollow flower-like MgAl2O4 spheres with abundant O vacancies for enhanced dry reforming of methane.

The dry reforming of methane (DRM) could convert CH4 and CO2 into syngas, offering potential for greenhouse gas mitigation. However, DRM catalyst sintering and carbon deposition remain major obstacles. In this study, a highly dispersed PtNi alloy@Zr-doped 3D hollow flower-like MgAl2O4 (AMO) spheres was prepared through a hydrophobic driving strategy. During a 50-hour test at 550°C, the catalyst exhibited no significant decline in CH4 and CO2 conversion rates, demonstrating its excellent anti-sintering and anti-coking performance. The unique anti-coking performance can be attributed to Zr-induced oxygen vacancies, which enhance oxygen mobility and reduce carbon deposition. Besides, doped Zr increases basic active sites, enhancing CO2 adsorption and activation, thus accelerating carbon species conversion. At 700°C, the unique synergy between highly dispersed Pt and Ni enabled CH4 and CO2 conversion rates to reach 67.5% and 73.8%, respectively. The incorporation of Pt or Zr extends the Ni-Ni bond and partially coordinates with Ni, enhancing the stability of the Ni lattice. The reaction of CH4 and CO2 follows the Langmuir-Hinshelwood (L-H) mechanism, where both reactant molecules are adsorbed and activated on the metallic sites. Moreover, the effective energy barrier for the CH oxidation pathway is lower by 0.16eV than that for the C oxidation pathway, which helps suppress the formation of carbon deposits.

Metal-free four-component coupling of cyclic diarylchloronium salts, tetrahydrothiophene, amines and carbon dioxide

A four-component coupling reaction of cyclic diarylchloronium salts, tetrahydrothiophene, amines and CO2 has been reported for the first time under transition metal-free conditions, giving rise to a range of structurally...

First-principles study of CO2 and H2O adsorption on the anatase TiO2(101) surface: effect of Au doping.

Photocatalytic reduction of CO2 will play a major role in future energy and environmental crisis. To investigate the adsorption mechanisms of CO2 and H2O molecules involved in the catalytic process on the surface of anatase titanium dioxide 101 (TiO2(101)) and the influence of Au atom doping on their adsorption, first-principles density functional theory calculations were used. The results show that 1. Au atom doping stabilizes the structure of the catalyst system and reduces the band gap, facilitating the reaction of CO2 and H2O molecules. 2. The O site is the most stable adsorption site for the CO2 molecule on the surface, and chemical adsorption occurs, leading to structural deformation during the adsorption process. The adsorption energy is the highest when the H2O molecule is adsorbed parallel to the surface, and there is a bonding trend between H2O and the surface. 3. The adsorption performances of CO2 and H2O molecules improve after Au atom doping. 4. Au atom doping creates stronger adsorption sites on the catalyst surface, with the two-coordinated O atoms near the Au atom becoming the preferred adsorption sites for both molecules. The revealed microscopic mechanism provides theoretical support for the design and manufacture of photocatalytic CO2 reduction catalysts.

Advanced systems for enhanced CO2 electroreduction.

Carbon dioxide (CO2) electroreduction has extraordinary significance in curbing CO2 emissions while simultaneously producing value-added chemicals with economic and environmental benefits. In recent years, breakthroughs in designing catalysts, optimizing intrinsic activity, developing reactors, and elucidating reaction mechanisms have continuously driven the advancement of CO2 electroreduction. However, the industrialization of CO2 electroreduction remains a challenging task, with high energy consumption, high costs, limited reaction products, and restricted application scenarios being the issues that urgently need to be addressed. To accelerate the progress of CO2 electroreduction towards practical application, this review shifts the research focus from catalysts to aspects such as reactions and systems, aiming to improve reaction efficiency, reduce technical costs, expand the range of products, and enhance selectivity, offering readers a new perspective. In particular, innovative and specific design strategies such as CO2 reduction coupled with alternative oxidation, co-reduction reaction of CO2 and C/N/O/S-containing species, cascade systems, and integrated CO2 capture and reduction systems are discussed in detail. Additionally, personal views on the opportunities and future challenges of the aforementioned innovative strategies are provided, offering new insights for the future research and development of CO2 electroreduction.

Unraveling the C-C Coupling Mechanism on Dual-Atom Catalysts for CO2/CO Reduction Reaction: The Critical Role of CO Hydrogenation.

The electrochemical reduction reaction (RR) of CO to high value multicarbon products is highly desirable for carbon utilization. Dual transition metal atoms dispersed by N-doped graphene are able to be highly efficient catalysts for this process due to the synergy of the bimetallic sites for C-C coupling. In this work, we screened homonuclear dual-atom catalysts dispersed by N-doped graphene to investigate the potential in CO reduction to C2+ products by employing density functional theory calculations. We have demonstrated that the two adsorbed CO species on bimetallic sites cannot directly couple unless one of the CO molecules is hydrogenated. All the dual metal atom catalysts prefer a similar coupling mechanism, i.e., the asymmetric coupling of *CO on the bridged site and *CHO on the top site, while the Ni2 and Cu2 catalysts exhibit much better performance with moderate adsorption energies and low energy barriers. The enhanced activities are attributed to the decrease of the energy levels of *CO 2p states that weakens the metal-C bonding and thus facilitates the feasible C-C coupling with both low reaction energies and low barriers. These insights have revealed the significant role of the hydrogenation of CO species prior to the coupling step and may provide a theoretical perspective to understand the generation of C2+ products in the CO2/CORR.

Optimization Strategies for Electrocatalytic CO2 Reduction Based on Atomically Dispersed Copper: A Review

AbstractThe electroreduction reaction of CO2 (eCO2RR) is considered an effective pathway for clean fuel production, greenhouse gas reduction, and resource recycling. Atomically dispersed catalysts exhibit excellent catalytic activity due to the high dispersion of atoms, especially for atomically dispersed copper (AD Cu). Although copper‐based materials are considered major single component materials capable of producing multi‐carbon products, the reaction mechanism is usually not very clear. For AD Cu catalysts, the dynamic transformation of Cu species in the form of single atoms, (nano)clusters, and ions during the reaction process significantly has an effect on the performance of eCO2RR. The core issue that needs to be addressed is how to control and tune the aggregation of Cu atoms to make it most favorable for the desired product or reaction pathways. This review summarizes the optimization strategies for AD Cu in recent years from three main perspectives: interface engineering, electrode engineering, and external field coupling.

Solid Solution Derived Cu Clusters on Partially Reduced CuCeO2 with Abundant Oxygen Vacancies Enable Efficient Reverse Water Gas Reaction.

The reverse water gas shift (RWGS) reaction provides a convenient approach to convert CO2 to CO, which facilitates to achieve the goals of carbon peaking and carbon neutrality. Herein, the Cu/CeO2 catalyst prepared by a co-precipitation method using a mixture of Na2CO3 and NaOH at pH of 10 (sample Cu/CeO2-10) achieved an intrinsic reaction rate of 428.4 mmol ⋅ gcat -1 ⋅ h-1 with 100 % CO selectivity at 400 °C and CO2/H2 ratio of 1 : 4, which is much higher than Cu/CeO2 prepared by impregnation and other methods. Various characterizations showed the highest fraction of CuCeO2 solid solution in the calcined Cu/CeO2-10, and formed highly dispersed Cu clusters (~2.5 nm) on partially reduced CuCeO2 solid solution with abundant of oxygen vacancies upon reduction. The Cu and oxygen vacancies facilitates the activation of H2 and CO2, respectively, resulting in lowered H2 and CO2 reaction orders. As a result, the synergy between the two components enhanced the overall RWGS activity with lowered activation energy. Moreover, the optimal catalyst is very stable in 24 h stability test without detectable agglomeration of Cu clusters.

Sulfonic group functionalized task specific ionic liquid as catalyst for Biginelli reaction in water and Co2+/Ni2+ separation from their aqueous mixture

A new hydrophobic ionic liquid 1,3-dihexylimidazolium-5-sulfosalicylate [DHIm] + [5-SSA]− was synthesized and characterized. The sulfonic-functionalized IL was effectively employed in the Biginelli reaction under ultrasound irradiation. The [DHIm] + [5-SSA]− demonstrated efficient catalytic performance yielding up to 83% product. Additionally, the application of [DHIm] + [5-SSA]− in selective extraction of Co2+ and Ni2+ from their aqueous mixture has been successfully carried out. High extraction efficiency was observed for Co2+.

Quaternary ammonium salt functionalized copper phthalocyanine-graphene oxide hybrids for cocatalyst-free carbon dioxide cycloaddition

Chemical conversion of carbon dioxide (CO2) into high-value products not only enhances environmental sustainability but also presents economic benefits. The development of novel and effective catalysts is crucial for facilitating the conversion of CO2 and the synthesis of these chemicals. In this study, we present the preparation of an ionic liquid-functionalized graphene oxide and copper phthalocyanine (CuPc) hybrid (GO-CuPc-IL). This was achieved through the chemical grafting of phthalonitrile groups and quaternary ammonium salts onto graphene oxide (GO), followed by in situ polymerization with phloroglucinol triphenyldinitrile. This hybrid catalyst was employed to catalyze the cycloaddition reaction of CO2 with epoxides under mild conditions. A series of analytical techniques confirmed the successful synthesis of the GO-CuPc-IL. The presence of abundant hydrogen bond donor groups (urea groups), Lewis acidic sites (coordinated copper rings), phthalocyanine rings, and numerous ionic active sites within the GO-CuPc-IL significantly facilitated the activation of reactants, enabling an efficient cycloaddition reaction of CO2 and epoxides. Notably, with 3.0 wt% of GO-CuPc-IL, the reaction achieved a yield of 98% and a selectivity of 99% at 1.5 MPa CO2 and 100 °C for 8 h, along with remarkable stability and reusability. This innovative hybrid catalyst promotes the simultaneous adsorption and activation of CO2 and epoxide by immobilizing multiple functional groups on the catalyst support, providing new avenues for sustainable CO2 conversion.