CO2 Complex Research Articles

A robust floating oxygen-doped graphitic carbon nitride sheet for efficient photocatalytic CO2 conversion

Photocatalytic CO2 reduction offers a promising approach for converting CO2 into valuable chemicals. However, typical conversion systems suffer from inefficient CO2 mass transfer and complex recycling processes. In this study, we developed a floating sheet as a robust photocatalytic CO2 conversion system by integrating graphitic carbon nitride (CN) nanosheets onto polytetrafluoroethylene (PTFE) fiber membrane, followed by oxygen (O) doping into the CN (CN-O) via oxygen-plasma treatment. The floatable CN-O/PTFE sheet exhibits slight wettability in water under 0.25 MPa of CO2 pressure in our reactor system, facilitating the delivery of dissolved CO2 to the CN-O photocatalyst surface. O-doping enhances the visible light absorption and improves the separation and transport efficiency of photogenerated electrons and holes due to O-doping-induced states in CN. Consequently, the floating CN-O/PTFE system achieves an exceptional photocatalytic CO2 conversion rate of 102.3 μmol g-1h-1, approximately 4.8 times higher than a conventional CN-powder dispersion system in water. Moreover, the sheet demonstrates excellent cycling durability, with no significant exfoliation of the catalytic layer or reduction in CO2 photoreduction activity after 20 consecutive cycles. This study presents a novel approach to designing photocatalytic systems for efficient CO2 conversion.

Mechanism of efficient electroreduction of CO2 to CO at Ag electrode in imidazolium-based ionic liquids/acetonitrile solution

Imidazolium-based ionic liquids (Imim-ILs) have great application potential in catalyzing the electrochemical CO2 reduction reaction (CO2RR). However, the microscopic mechanism by which imidazolium-based cations promote CO2RR remains unclear. In this study, we observe that despite the structural differences between [Bmmim]+ and [Bmim]+, both exhibit high catalytic activity during the electrochemical CO2RR. Electrochemical and in situ spectroscopic analyses, as well as Quantum Theory of Atomic in Molecules (QTAIM), reveal that the pivotal step in the CO2RR mechanism facilitated by [Bmmim]+ and [Bmim]+ involves the formation of [Bmmim]···CO2 or [Bmim]···CO2 complexes via hydrogen bond. These complexes enhance the electrochemical reduction of CO2 or ·CO2- on electrode, facilitating efficient CO production. Specifically, the [Bmmim]···CO2 complex forms at the C4-H position of the imidazole ring, while in the [Bmim]···CO2 complex, it forms at the C2-H position.

Analysis of Fracturing Expansion Law of Shale Reservoir by Supercritical CO2 Fracturing and Mechanism Revealing

The rapid expansion of reservoir fractures and the enlargement of the area affected by working fluids can be accomplished solely through fracturing operations of oilfield working fluids in geological reservoirs. Supercritical CO2 is regarded as an ideal medium for shale reservoir fracturing owing to the inherent advantages of environmental friendliness, excellent capacity, and high stability. However, CO2 gas channeling and complex propagation of fractures in shale reservoirs hindered the commercialization of Supercritical CO2 fracturing technology. Herein, a simulation method for Supercritical CO2 fracturing based on cohesive force units is proposed to investigate the crack propagation behavior of CO2 fracturing technology under different construction parameters. Furthermore, the shale fracture propagation mechanism of Supercritical CO2 fracturing fluid is elucidated. The results indicated that the propagation ability of reservoir fractures and Mises stress are influenced by the fracturing fluid viscosity, fracturing azimuth angle, and reservoir conditions (temperature and pressure). An azimuth angle of 30° can achieve a maximum Mises stress of 3.213 × 107 Pa and a crack width of 1.669 × 10−2 m. However, an apparent viscosity of 14 × 10−6 Pa·s results in a crack width of only 2.227 × 10−2 m and a maximum Mises stress of 4.459 × 107 Pa. Additionally, a weaker fracture propagation ability and reduced Mises stress are exhibited at the fracturing fluid injection rate. As a straightforward model to synergistically investigate the fracture propagation behavior of shale reservoirs, this work provides new insights and strategies for the efficient extraction of shale reservoirs.

Unveiling the Reactivity of Part Per Million Levels of Cobalt-Salen Complexes in Hydrosilylation of Ketones.

A series of air-stable cobalt(III)salen complexes Co-1 to Co-4 have been synthesized and employed in the hydrosilylation of ketones. Notably, the most intricately tailored Co-3 pre-catalyst exhibited exceptional catalytic activity under mild reaction conditions. The developed catalytic hydrosilylation protocol proceeded with an unusual ppm level (5 ppm) catalyst loading of Co-3 and achieved a maximum turnover number (TON) of 200,000. A wide variety of aromatic, aliphatic, and heterocyclic ketones encompassing both electron-donating and electron-withdrawing substituents were successfully transformed into the desired silyl ethers or secondary alcohols in moderate to excellent yields.

Weakly bound complexes of 1,2,3-triazole with nitrogen and carbon dioxide isolated in solid argon: A combined FT-IR matrix isolation and theoretical investigation

Matrix isolation FT-IR spectroscopy was combined with quantum-chemical calculations in order to characterize complexes of 1,2,3-triazole (3TR) with nitrogen and carbon dioxide. Geometries of the possible 1:1 and 1:2 complexes, as well as 3TR dimers, were optimized at the DFT (B3LYP-D3) level of theory with the 6–311++G(3df,3pd) basis set. Six different 3TR⋯N2 structures of the 1:1 stoichiometry were optimized which are characterized by weak hydrogen bonds (N-H⋯N and C-H⋯N) and/or Van der Waals type interactions (N⋯C, N⋯N, N⋯π). Two the most stable geometries, both containing a N-H⋯N bridge, were identified experimentally in solid argon. As for 3TR⋯CO2 complexes, out of two minima located on the potential energy surface, only one with a strongly bent N-H⋯O hydrogen bond was detected in the matrix after deposition. In both cases, only annealing experiments at 32 K resulted in the formation of small amounts of 1:2 structures.

Capture of CO2 by Melamine Derivatives: A DFT Study Combining the Relative Energy Gradient Method with an Interaction Energy Partitioning Scheme.

A theoretical study of the interaction between melamine and CO2 was carried out using density functional theory (DFT) with the B3LYP-D3(BJ)/aug-cc-pVTZ level of theory. The presence of anions interacting with melamine transforms the weakly bonded tetrel complexes into adducts. Thus, melamine acts as an FLP (frustrated Lewis pair) with acid groups (NHs as hydrogen bond donors) and a base group (N of the triazine ring). The application of the relative energy gradient formalism (REG) along the reaction coordinate has demonstrated that the ability of the melamine-anion systems to capture CO2 is linked to its capacity to polarize the CO2 molecule. These results have been confirmed by placing the melamine:CO2 complex in a uniform electric field with different strengths.

Amidinatotetrylenes Donor Functionalized on Both N Atoms: Structures and Coordination Chemistry.

E(hmds)(bqfam) (E = Ge (1a), Sn (1b); hmds = N(SiMe3)2, bqfam = N,N'-bis(quinol-8-yl)formamidinate), which are amidinatotetrylenes equipped with quinol-8-yl fragments on the amidinate N atoms, have been synthesized from the formamidine Hbqfam and Ge(hmds)2 or SnCl(hmds). Both 1a and 1b are fluxional in solution at room temperature, as the E atom oscillates from being attached to the two amidinate N atoms to being chelated by an amidinate N atom and its closest quinolyl N atom (both situations are similarly stable according to density functional theory calculations). The hmds group of 1a and 1b is still reactive and the deprotonation of another equivalent of Hbqfam can be achieved, allowing the formation of the homoleptic derivatives E(bqfam)2 (E = Ge, Sn). The reactions of 1a and 1b with [AuCl(tht)] (tht = tetrahydrothiophene), [PdCl2(MeCN)2], [PtCl2(cod)] (cod = cycloocta-1,5-diene), [Ru3(CO)12] and [Co2(CO)8] have been investigated. The gold(I) complexes [AuCl{κE-E(hmds)(bqfam)}] (E = Ge, Sn) have a monodentate κE-tetrylene ligand and display fluxional behavior in solution the same as that of 1a and 1b. However, the palladium(II) and platinum(II) complexes [MCl{κ3E,N,N'-ECl(hmds)(bqfam)}] (M = Pd, Pt; E = Ge, Sn) contain a κ3E,N,N'-chloridotetryl ligand that arises from the insertion of the tetrylene E atom into an M-Cl bond and the coordination of an amidinate N atom and its closest quinolyl N atom to the metal center. Finally, the binuclear ruthenium(0) and cobalt(0) complexes [Ru2{μE-κ3E,N,N'-E(hmds)(bqfam)}(CO)6] and [Co2{μE-κ3E,N,N'-E(hmds)(bqfam)}(μ-CO)(CO)4] (E = Ge, Sn) have a related κ3E,N,N'-tetrylene ligand that bridges two metal atoms through the E atom. For the κ3E,N,N'-metal complexes, the quinolyl fragment not attached to the metal is pendant in all the germanium compounds but, for the tin derivatives, is attached to (in the Pd and Pt complexes) or may interact with (in the Ru2 and Co2 complexes) the tin atom.

Proton Transfer via π-Interactions from Pyridine Provides a Facilitated Route for Transfer of CO2 in Its Complex with a Carbanion.

Aromatic π-interactions have been recognized as enhancing enzymatic catalytic processes, providing an efficient route to overcome entropic barriers. A nonenzymic analogue, a complex of protonated pyridine and a phenyl substituent in a thiamin conjugate, facilitates the departure of CO2 by protonation of a vicinal carbanion in a reactive complex. To evaluate the efficiency of the catalytic pathway from the π-associated proton donor, a system was assessed that produced measurable competition through the rates of formation of alternative products resulting from the same thiamin-derived carbanion. The barriers to competing pathways from the decarboxylation of p-(bromomethyl)-mandelylthiamin in the presence and absence of protonated pyridine were determined, establishing the efficiency of the vicinal proton transfer between π-associated species. The formation of the complex of CO2 and the co-formed carbanion also addresses the mechanism of the uncatalyzed exchange of 13CO2 into carboxyl groups discovered by Lundgren. Finally, microscopic reversibility implicates pyridine as a vicinal Brønsted base in thiamin-aldehyde adducts, producing carbanions that could incorporate dissolved CO2 into carboxyl groups.

Reduction of CO2 in the presence of light via excited-state hydride transfer reaction in a NADPH-inspired derivative.

The photo-catalytic reduction of CO2 into chemical feedstocks using solar energy has attracted vast interest in environmental science because of global warming. Based on our previous study on the CO2 complex with one of the benzimidazoline (BI) derivatives, we explore the photochemical reduction of CO2 in one of the benzimidazoline derivatives (1,3-dimethyl-5,6-diol-2,3-dihydro-1H-benzimidazole) by quantum-chemical methods. Our results reveal that carbon dioxide can be reduced to formate (HCOO-) by a hydride transfer reaction in the excited state of this complex of benzimidazoline derivative and CO2. While the ground-state hydride transfer reaction in this complex exhibits a substantial barrier, a charge-transfer can occur in the first singlet excited state of the complex in the UV-A region (326 nm), and after overcoming a moderate barrier (∼0.4 eV) the system can have access to the products. The interaction with a polar solvent decreases further the barrier such that the reaction in dimethyl sulfoxide can proceed with a negligibly small barrier (∼0.1 eV) or in a nearly barrierless manner. Our results show that this benzimidazoline derivative may act as a catalyst in the photoreduction of CO2.

Electron-rich pyridines with para-N-heterocyclic imine substituents: ligand properties and coordination to CO2, SO2, BCl3 and PdII complexes.

Electron-rich pyridines with π donor groups at the para position play an important role as nucleophiles in organocatalysis, but their ligand properties and utilization in coordination chemistry have received little attention. Herein, we report the synthesis of two electron-rich pyridines 1 and 2 bearing N-heterocyclic imine groups at the para position and explore their coordination chemistry. Experimental and computational methods were used to assess the donor ability of the new pyridines showing that they are stronger donors than aminopyridines and guanidinyl pyridines, and that the nature of the N-heterocyclic backbone has a strong influence on the pyridine donor strength. Coordination compounds with Lewis acids including the CO2, SO2, BCl3 and PdII ions were synthesized and characterized. Despite the ambident character of the new pyridines, coordination preferentially occurs at the pyridine-N atom. Methyl transfer experiments reveal that 1 and 2 can act as demethylation reagents.

Sensing ability of carbon nitride (C6N8) for the detection of carbon monoxide (CO) and carbon dioxide (CO2)

Carbon nitride (C6N8) is explored as an adsorption material for harmful industrial gases such as carbon monoxide (CO) and carbon dioxide (CO2). The complexation of CO and CO2 with C6N8 (analyte@C6N8) is deeply studied by the analyses of interaction energy (IE), frontier molecular orbital (FMO), non-covalent interactions (NCI), natural bond orbital (NBO), Bader’s quantum theory of atoms in molecules (QTAIM), density of state (DOS), reduced density gradient (RDG), and electron localization function (ELF). The results of interaction energy (−18.870 kJ/mol to −14.991 kJ/mol) showed the adsorption strength of CO and CO2 gases on the C6N8 surface. NCI and QTAIM investigations demonstrated that non-covalent interactions occurred in CO2 @C6N8 and CO@C6N8 complexes. The NCI and RDG analyses indicated surface interaction with CO and CO2 gases. The emergence of novel energy levels in the DOS spectrum highlighted the system's susceptibility to contaminants and the development of new excited states in the PDOS spectrum demonstrated the chemical reactivity of complexes. Moreover, the results of QNBO show that surface (C6N8) extracted a relatively greater amount of charge from CO (0.018 e−1) as compared to CO2 (0.006 e−1). At 300 K, the analyte@C6N8 complexes recovery time (4.06 ×10−10 s and 1.92 ×10−9 s) showed sensing behavior of surface for CO and CO2 gases. Our results suggested that the C6N8 surface is a superb option for CO and CO2 gases.

Solid state conversion of novel coordinated precursors to visible light active photocatalysts with enhanced photocatalytic activity

The new polydentate N'1,N'3‐bis((E)‐3‐oxopentan‐2‐ylidene)malonohidrazide chelating agent (H2L) and its coordinated complexes of Co2+, Cu2+, and Ni2+ were prepared and characterized by elemental analysis, molar conductance, and spectra (Fourier transform infrared [FT‐IR], ultraviolet–visible spectroscopy [UV–vis], and Fast‐Atom Bombardment Mass Spectrometry (FAB‐MS). Also, thermal and magnetic investigations were conducted. X‐ray single crystal of the H2L ligand revealed a triclinic structure with space group P‐1. In this study, we provide a one‐pot preparation approach for transition metal oxide nanoparticles (NPs) such as CuO, Co3O4, and NiO NPs. The methodology entails the thermal decomposition of coordinated metal precursors in a solid‐state environment, obviating the necessity for agitation and rinsing. The remarkable significance of this method lies in its ability to produce highly pure NPs without the requirement of washing, and it allows for systematic and efficient production. Herein, we propose a large‐scale, environmentally benign and renewable, transition metals oxide NPs such as CuO, Co3O4, and NiO using solid‐state thermal degradation of their coordinated precursors. The NPs are subjected to analysis employing a range of techniques, such as X‐ray powder diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), N2 sorpometry (BET), and UV–vis). The photocatalytic activities of the synthesized NPs were assessed using photodegradation of organic contaminants in wastewater.

Ionic liquid promotes the efficient photocatalytic reduction of CO2 by Cu nanodots modified oxygen-vacancy Bi2MoO6

The conversion of CO2 into useful chemical fuels through solar photocatalysis is an important means to alleviate energy and environmental problems. In this work, small-sized Cu nanodots were dispersed on the surface of bismuth molybdate containing oxygen vacancies. The Cu/ILs/OVs-BMO composite photocatalyst with high photocatalytic reduction activity was obtained. The small size of Cu nanodots can not only greatly improve the visible light absorption of the composite catalyst, but also establish an effective channel for charge transport through the close interaction between Cu nanodots and bismuth molybdate, which promotes the efficient separation of photogenerated charge carriers and increases the photocurrent by 11.04 times. The CO2 photocatalytic reduction interface reaction was improved by adding an amine-based functionalized ionic liquid. The complexation of ILs and CO2 decreased the activation energy of generating CO2 intermediate and the overpotential of the reaction. Compared with BMO, the yield of the liquid products on Cu/ILs/OVs-BMO photocatalyst increased by 17.80 times.

Sustainable System for CO2 Capturing with Multiple Products

Currently, we are facing several serious issues, including diseases, climate change, economics, and wars. Among them, which needs to be resolved imminently to protect the future generations. Recently, we developed an innovative CO2 fixation and storage method based on the use of chemical compounds such as NaOH and CaCl2, to prevent the climate crisis. Herein, the electrolysis of a NaCl solution or seawater was performed to make the resultant NaOH react with CO2. Amines that react with CO2 were also examined. Moreover, seawater was used to produce CaCO3 rather than the CaCl2 solution. Although amines are currently used to capture CO2 from exhaust gases, the thermal treatment of the amine–CO2 complex solution is necessary to release CO2. Thermal treatment requires energy that eventually produces CO2 and induces the degradation of organic amines. However, the CO2 captured in the amine or NaOH solution was released easily by acidifying the CO2-containing solutions. Moreover, HCl could release CO2 from hydro carbonates, Ca(OH)2, Mg(OH)2, and mMgCO3·Mg(OH)2·nH2O, as well as from mineral carbonates, CaCO3 and MgCO3. This simple method of releasing the captured CO2 from the amine–CO2 complexes, hydro carbonates, and mineral carbonates is crucial to obtain pure CO2 for additional usage as an original material.

On the origin of carbon sources in the electrochemical upgrade of CO2 from carbon capture solutions

•Reacting bicarbonate and carbamate species on Ag electrodes requires energy input •On Ag electrodes, the carbon source is the free and dissolved CO2 during RCC •Carbamate species can only participate in RCC at highly negative potentials •Methods to measure and report dissolved CO2 concentration during RCC are developed Carbon capture and utilization (CCU) is a crucial technology for mitigating the effects of climate change. One approach to CCU is reactive carbon capture (RCC), which integrates (1) the capture and concentration of CO2 in a capture medium via the reversible formation of a chemical complex with a molecular capture agent, such as an amine, and (2) the direct transformation of the CO2 complex into a fuel or chemical. CO2 capture media present a large degree of speciation, where carbon exists in different molecular configurations with different energy states and barriers to reaction. In this work, a combination of first principle modeling and experimental electrochemical characterization methods reveal that unbound dissolved CO2 is the primary carbon species being consumed during the electrochemical reduction of bicarbonate and amine-based CO2 capture solutions on silver electrodes. Carbon in the CO2-absorber complex occurs to serve as a second carbon source only at highly negative potential. Carbon capture and utilization (CCU) is a crucial technology for mitigating the effects of climate change. One approach to CCU is reactive carbon capture (RCC), which integrates (1) the capture and concentration of CO2 in a capture medium via the reversible formation of a chemical complex with a molecular capture agent, such as an amine, and (2) the direct transformation of the CO2 complex into a fuel or chemical. CO2 capture media present a large degree of speciation, where carbon exists in different molecular configurations with different energy states and barriers to reaction. In this work, a combination of first principle modeling and experimental electrochemical characterization methods reveal that unbound dissolved CO2 is the primary carbon species being consumed during the electrochemical reduction of bicarbonate and amine-based CO2 capture solutions on silver electrodes. Carbon in the CO2-absorber complex occurs to serve as a second carbon source only at highly negative potential.

Mechanism of selective transportation of metal ions across chelating membranes in electrodialysis

The presented research explains the mechanism of selective transportation mass in electrodialysis by chelating membrane according to the electrosorption and specific diffusivity. The Nernst-Planck equation was applied for modelling and defining the character of mass transportation. The chelating membrane is developed by the chemical grafting of hydroxyquinoline (HQ), which guarantees selectivity. The investigation of mass transportation was determined using a single-component solution of transition metal cations like Co2+, Mn2+and Ni2+, as well as from alkaline metal classes like Li+ and Mg2+. Finally, the multi-component solutions were tested to confirm the chelating membrane's specific character and mass transportation mechanism. The chemical and electrochemical investigations like FTIR and EIS confirmed the appearance of the chelating reactions between membrane and cobalt cations only. According to the creation of aqua complexes of HQ and Co2+, the PAN-5C8Q membrane could transport in a significant majority only Co2+ against other mono- and divalent cations. The transport number against the Mn2+, Ni2+, Mg2+ and Li+ for Co2+got over 0.6.

Transition metal (X = Mn, Fe, Co, Ni, Cu, Zn)-doped graphene as gas sensor for CO2 and NO2 detection: a molecular modeling framework by DFT perspective.

In this research, CO2 and NO2 adsorption on doped nanographene (NG) sheets with transition metals (Fe, Ni, Zn) and (Mn, Co, Cu), respectively, have been applied for scavenging of these toxic gases as the environmental pollutants. The values of changes of atomic charge density have illustrated a more significant charge transfer for Ni-doped C-NG through CO2 adsorption and a more remarkable charge transfer for Co-doped C-NG through NO2 adsorption. The data of NMR spectroscopy has depicted several fluctuations around the graph of Zn-doped on the nanographene surface. The thermodynamic results from IR spectroscopy have indicated that [Formula: see text] values are almost similar for doped metal transitions of Mn, Co, and Cu on the C-NG nanosheet, while [Formula: see text] has the largest gap of Gibbs free energy adsorption with dipole moment. The Langmuir adsorption model with a three-layered ONIOM using CAM-B3LYP functional accompanying LANL2DZ, EPR-III and 6-31 + G (d,p) basis sets due to Gaussian 16 revision C.01 program on the complexes of CO2 → (Fe, Ni, Zn) and NO2 → (Mn, Co, Cu) doped on the C-NG has been accomplished. Then, NMR and IR spectroscopy, nuclear quadrupole resonance, and natural bond orbital analysis have been accomplished for evaluating chemical shielding tensors, thermodynamic properties, electric potential, and occupancy fluctuation through bond orbitals, respectively. In addition, frontier orbitals of LUMO, HOMO, and also a series of chemical reactivity parameters have been calculated. Finally, time-dependent-DFT method due to UV-VIS spectrums has been accomplished to discern the low-lying excited states of CO2 and NO2 adsorption on the (Fe, Ni, Zn) and (Mn, Co, Cu), respectively, doped C-NG sheet.

Crosslinking two-dimensional metalloporphyrin (Me-TCPP) nanosheet with poly(ethylene) glycol semi-interpenetrating polymer network for ultrahigh CO2/N2 separation selectivity via “rubber-band” straightening effect

To efficient separate carbon dioxide from power plant flue gas, three two-dimensional (2D) metalloporphyrin (Me-TCPP) nanosheets, Zn-TCPP, Cu-TCPP, and Ni-TCPP are crosslinked with poly(ethylene) glycol (PEO) semi-interpenetrating polymer via “rubber-band” straightening effect. Dispersion-corrected periodic density functional (DFT-D2) calculation reveals that the lowest N4-Metalδ+···Oδ− distance (2.81 Å) and the highest binding energy (19.9 kJ mol−1) are obtained between CO2 molecule and metalloporphyrin center (Zn–N4), as well as the lowest O4-Metalδ+···Oδ− distance (4.68 Å) and the highest binding energy (18.8 kJ mol−1) on metal cluster (Zn–O4). The 2D Zn-TCPP nanosheet with the strongest affinity toward CO2 molecule generates Zn2+-CO2 complex to remarkably boost CO2 solubility in mixed matrix membrane (MMMs). Thus, 2.5 wt% Zn-TCPP nanosheet incorporated PEO-based MMMs dramatically promotes CO2 permeability to 198 Barrers and ultrahigh CO2/N2 selectivity to 81. A novel “rubber-band” straightening effect is found and verified, which is induced by abundant interfacial coordination bonds between metal ions in nanosheets and ester groups (O–CO) in PEO polymer chains, the strong Me–O–CO interaction sites hold polymer chains and lead to their regular rearrangement. Owing to the abundant PEG groups in PEGMEA macromolecule chains, incorporating 1 wt% Zn-TCPP nanosheet into crosslinked XLPEGDAcoPEGMEA polymer achieves the highest CO2 permeability of 398 Barrers.

Graphene Embedded with Transition Metals for Capturing Carbon Dioxide: Gas Detection Study Using QM Methods

Carbon dioxide (CO2) adsorption on decorated graphene (GR) sheets with transition metals (TMs) including iron, nickel and zinc was investigated for removing this hazardous gas from the environment. TM-doped GR results in higher activity toward gas detecting than pristine graphene nanosheets. TM embedding restrains hydrogen evolution on the C sites, leaving more available sites for a CO2 decrease. The Langmuir adsorption model with ONIOM using CAM-B3LYP functional and LANL2DZ and 6-31+G (d,p) basis sets due to Gaussian 16 revision C.01 program on the complexes of CO2→(Fe, Ni, Zn) embedded on the GR was accomplished. The changes of charge density illustrated a more considerable charge transfer for Zn-embedded GR. The thermodynamic results from IR spectroscopy indicated that ΔGads,CO2→Zn@C−GRo has the notable gap of Gibbs free energy adsorption with a dipole moment which defines the alterations between the Gibbs free energy of the initial compounds (ΔGCO2 o and ΔGZn@C−GRo) and product compound (ΔGCO2→Zn@C−GRo) through polarizability. Frontier molecular orbital and band energy gaps accompanying some chemical reactivity parameters represented the behavior of molecular electrical transport of the (Fe, Ni, Zn) embedding of GR for the adsorption of CO2 gas molecules. Our results have provided a favorable understanding of the interaction between TM-embedded graphene nanosheets and CO2.

Diverse Cooperative Reactivity at a Square Planar Aluminium Complex and Catalytic Reduction of CO2.

The use of a sterically demanding pincer ligand to prepare an unusual square planar aluminium complex is reported. Due to the constrained geometry imposed by the ligand scaffold, this four-coordinate aluminium centre remains Lewis acidic and reacts via differing metal-ligand cooperative pathways for activating ketones and CO2 . It is also a rare example of a single-component aluminium system for the catalytic reduction of CO2 to a methanol equivalent at room temperature.