CO Molecules Research Articles

Molecular simulation study of adsorption-diffusion of CH4, CO2 and H2O in gas-fat coal

In order to clarify the microscopic dynamics mechanism of CH4, CO2 and H2O adsorption and diffusion in coal, and to reveal the mechanism of the influence of different temperatures and pressures on the adsorption and diffusion characteristics of coal adsorbed CH4, CO2 and H2O molecules. In this paper, the macromolecular structure model of Jixi gas-fat coal was constructed, based on the Giant Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) methods. The adsorption-diffusion characteristics of CH4,CO2 and H2O single-component gases in the gas-fat coal macromolecule model at temperatures ranging from 273.15 K to 313.15 K and pressures ranging from 0.01 MPa to 15 MPa were investigated by using Material Studio software. The research results indicated that: The adsorption of three gases, CH4, CO2 and H2O, increased with the increase of equilibrium pressure, and the adsorption isotherms conformed to Langmuir type I isotherms. The amount of saturated adsorption of CH4 ranged from 11.18 to 14.37 ml/g, the saturated adsorption of CO2 ranged from 20.40 to 24.70 ml/g, and the saturated adsorption of H2O ranged from 66.61 to 84.21 ml/g. With the increase of temperature, the saturated adsorption of CH4 and CO2 both decreased, and the saturated adsorption of H2O firstly increased and then decreased, and the adsorption of H2O by low temperature and high temperature had both an inhibitory effect on the adsorption of H2O. The potential energy distributions of CH4, CO2 and H2O molecules are poisson distributed. The absolute values of the most available interaction energies are, from highest to lowest: H2O > CO2 > CH4; the activation energies for diffusion of CH4, CO2 and H2O are 12.20 kJ/mol, 3.36 kJ/mol, and 8.47 kJ/mol, respectively, and the diffusion of CO2 is the more likely to occur. The adsorption of CH4 and CO2 in coal is physical adsorption, while the adsorption process of H2O molecules is beyond the scope of physical adsorption. The absolute value of the interaction energy is H2O > CO2 > CH4 in descending order.

Radiation-Synthesized Metal-Organic Frameworks with Ligand-Induced Lewis Pairs for Selective CO2 Electroreduction.

The electrochemical activation of inert CO2 molecules through C─C coupling reactions under ambient conditions remains a significant challenge but holds great promise for sustainable development and the reduction of CO2 emission. Lewis pairs can capture and react with CO2, offering a novel strategy for the electrosynthesis of high-value-added C2 products. Herein, an electron-beam irradiation strategy is presented for rapidly synthesizing a metal-organic framework (MOF) with well-defined Lewis pairs (i.e., Cu- Npyridinic). The synthesized MOFs exhibit a total C2 product faradic efficiency of 70.0% at -0.88V versus RHE. In situ attenuated total reflection Fourier transform infrared and Raman spectra reveal that the electron-deficient Lewis acidic Cu sites and electron-rich Lewis basic pyridinic N sites in the ligand facilitate the targeted chemisorption, activation, and conversion of CO2 molecules. DFT calculations further elucidate the electronic interactions of key intermediates in the CO2 reduction reaction. The work not only advances Lewis pair-site MOFs as a new platform for CO2 electrochemical conversion, but also provides pioneering insights into the underlying mechanisms of electron-beam irradiated synthesis of advanced nanomaterials.

Electrochemical conversion of CO2 via C−X bond formation: recent progress and perspective

With the depletion of traditional energy sources and growing environmental concerns, it is becoming increasingly urgent to develop green, low-emission renewable energy technologies to replace fossil fuel-driven methods that emit carbon dioxide (CO2). Currently, the electrochemical production of high-value-added chemicals and fuels from CO2 has aroused great interest from scientists. However, to make full use of CO2 for the preparation of chemicals, it is necessary to expand the range of electrosynthesis methods, in particular by expanding reaction pathways through the reaction of CO2 with different substrates. In general, CO2 can form new covalent bonds with substrate molecules through the formation of C−X bonds, including C−H, C−C, C−N, C−O, and C−S bonds, which would expand the range of possible products by diversifying the reaction pathway. In this review, we focus on the research progress in electrochemical conversion of CO2 through C−X bond formation. We start by examining fundamentals of the reactions and summarizing the reaction modes. Next, we discuss the electrosynthesis of C−X bonds (C−H, C−C, C−N, C−O, C−S) using CO2 and different substrate molecules. Finally, (i) strategies for the design and activity optimization of catalyst materials and (ii) the future development of forming five types of bonds from CO2 and small molecules are discussed, along with an outlook on their future research prospects.

A calorimetric and Raman spectroscopy study on the phase behavior of DIOX + CO2 hydrate

This work presents a calorimetric and Raman spectroscopy investigation on the phase behavior of DIOX (1,3-Dioxolane) + CO2 hydrate. A high-pressure micro-differential scanning calorimeter (HP μ-DSC) was used to determine the phase equilibrium data of DIOX + CO2 hydrate formed at 1 mol% and 5.56 mol% DIOX. A high-pressure in situ Raman spectroscopy apparatus was used to record the transient CO2 Raman spectra. The spectra were employed to study CO2 incorporation into the hydrate cages during the DIOX hydrate formation process. The results indicate that the DIOX + CO2 hydrate formed at 5.56 mol% DIOX is more stable than that formed at 1 mol% DIOX. The amount of DIOX + CO2 hydrate is increased when increasing the pressure from 3.0 MPa to 4.8 MPa, and more CO2 molecules are captured in the hydrate. Through the in situ Raman spectroscopy experiments, it is found that DIOX hydrate formed quickly at the beginning of the experiment and CO2 molecules were trapped in the small cages more slowly than the incorporation of DIOX into the hydrate. The results reported in this work have confirmed the feasibility of using DIOX as a thermodynamic additive to promote the hydrate-based CO2 capture.

Cu−based bimetallic sites' p-d orbital hybridization promotes CO asymmetric coupling conversion to C2 products

Hampered by sluggish C−C coupling kinetics, the low selectivity and efficiency have limited industrial applications of CO2 reduction into valuable multi-carbon products. A direct coupling of CO molecules or their coupling after hydrogenation, followed by the final synthesis of C2 products, can help to overcome these limitations potentially. In this study, a detailed high-throughput screening of bimetallic site catalysts comprising copper (Cu) and 28 other metal (M) atoms was conducted. The metal atoms Cu and M were anchored on a carbon nanotube (CNT) with six nitrogen (N6) defects (CuMN6@CNT), which possesses effective dual active sites for C−C coupling. The calculated results demonstrate that the CuGaN6@CNT catalyst exhibited favorable selectivity, with low theoretical overpotentials of −0.23 and −0.34 eV for ethanol and ethylene, respectively, surpassing most reported catalysts. The synergistic effect of Ga and Cu sites, along with their p-d states hybridization, results in an enhancement of Cu's d state dispersion and energy barriers reduction for C−C coupling. Additionally, the strain effect of the substrate CNT exhibits a direct correlation with the catalytic performance of CuGaN6@CNT by adjusting the d-band center of the Cu site and p-band center of the Ga site. These findings provide a novel insights into the electrocatalytic reduction of CO into valuable C2 products using bimetallic single atom catalyst, offering significant guidance for future research endeavors in this field.

Spectroscopic, structural characterization, along with DFT calculation, of a new cadmium(II) acetato meso-arylporphyrin: Theoretical study on NO2, CO2, N2, NO2, and SO2 gas-sensing and analysis of electrical conductance and dielectric properties

The paper presents a combined experimental and computational investigation of the cadmium(II) (acetato)‑meso-tetra(para-methoxyphenyl)porphyrin ion complex [Cd(TMPP)(OAc)]- (complex 1), which was prepared by the reaction of [Cd(TMPP)] with an excess of NaOAc and crysptand-222 in chloroform. This new Cd(II) meso‑arylporphyrin was characterized by elementary analysis and UV–Vis, IR, and 1H NMR spectroscopic techniques along with single crystal X-ray diffraction. This later study shows that the Cd2+center ion adopts a distorted square pyramidal geometry and is coordinated by the four nitrogens of the TMPP porphyrinate and the oxygen atom of the acetato axial ligand. The intermolecular interactions in the crystal lattice of [Cd(TMPP)(OAc)]-, determined using the PLATON program and Hirshfeld surfaces analysis, are of types O__H…O, C__H…H, C__H…Cl, C__H…Cg and C__Cl…Cg (Cg is the centroid of a phenyl or a pyrrole ring) involving the [Cd(TMPP)(OAc)]- ion complex, the [Na(crypt-222)]+ counterion, and the chloroform and water molecules found in the crystal lattice of complex 1. Using DFT calculations at the DFT/B3LYP-D3/lanL2DZ level of theory HOMO–LUMO orbitals of 1 and several global reactive parameters of this compound were calculated. The 3D-MEP plots of [Cd(TMPP)(OAc)]- were also determined. This theoretical study includes the sensing properties of complex 1 and the NO2, CO2, N2, and SO2 gas molecules. Furthermore, experimental tests have been carried out concerning the impedance and dielectric spectroscopy of the InGa/[Cd(TMPP)(OAc)]/InGa device.

Visual and Gravimetric CO2 Sensing at High Humidity Levels Enabled by MOF‐804 Cofunctionalized with Ionic Liquid and m‐Cresol Purple

AbstractReal‐time monitoring of carbon dioxide (CO2) is imperative for medical diagnosis and effective environmental preservation. Despite the formidable challenge posed by the inherent chemical inertness of CO₂ molecules, a pioneering CO2 sensor based on MOF‐804 cofunctionalized with ionic liquid (IL) and m‐cresol purple (mCP) is successfully developed. By ingeniously integrating hydrogen bonding, electrostatic interactions, and hydrophobic properties within the sensitive layer, the sensor achieves a state‐of‐the‐art sensitivity (Δf = 384 Hz), an exceptionally vast detection range spanning 400–80 000 ppm, and remarkable stability with minimal sensitivity drift even at relative humidity (RH) levels exceeding 80%. Furthermore, the inherent gasochromic property, stemming from the zwitterionic mechanism, paves the way for innovative self‐sustaining CO2 test strips and groundbreaking applications, including CO2 tracking and CO2‐encrypted security labeling technology. Collectively, the realization of this ultra‐sensitive and robust CO2 monitoring approach, coupled with its CO2‐triggered visual and multifunctional capabilities, opens up novel avenues for dynamic CO2 detection, advanced military encryption strategies, and enhanced health management systems.

Stabilization of High-Valent Molecular Cobalt Sites through Oxidized Phosphorus in Reduced Graphene Oxide for Enhanced Oxygen Evolution Catalysis.

Heterogeneous molecular cobalt (Co) sites represent one type of classical catalytic sites for electrochemical oxygen evolution reaction (OER) in alkaline solutions. There are dynamic equilibriums between Co2+, Co3+ and Co4+ states coupling with OH-/H+ interaction before and during the OER event. Since the emergence of Co2+ sites is detrimental to the OER cycle, the stabilization of high-valent Co sites to shift away from the equilibrium becomes critical and is proposed as a new strategy to enhance OER. Herein, phosphorus (P) atoms were doped into reduced graphene oxide to link molecular Co2+ acetylacetonate toward synthesizing a novel heterogeneous molecular catalyst. By increasing the oxidation states of P heteroatoms, the linked Co sites were spontaneously oxidized from 2+ to 3+ states in a KOH solution through OH- ions coupling at an open circuit condition. With excluding the Co2+ sites, the as-derived Co sites with 3+ initial states exhibited intrinsically high OER activity, validating the effectiveness of the strategy of stabilizing high valence Co sites.

The effects of different functional groups in Ni3-cluster MOFs on the efficient capture and transformation for flue gas CO2

As the greenhouse effect continuous increasing, the efficient CO2 capture and conversion into high-value fine chemicals have been necessary and meaningful. However, the CO2 coupling reaction always requires harsh catalytic reaction conditions and focuses on pure CO2 gas. Herein, three nickel-cluster metal-organic frameworks (MOFs) with different functional groups on the bridging-ligands have been synthesized and characterized structurally, presenting unique cages and channels architectural features. Catalytic investigations demonstrated that the amino-functionalized MOFs as a catalyst {[H2N(CH3)2]2[Ni3(µ3-O)(XN)(BDC-NH2)3∙7DMF}n (Ni3-NH2, XN = 6′′-(pyridin4-yl)-4,2′′:4′′,4′′′-terpyridine, H2BDC-NH2 = 2-aminoterephthalic acid) owns higher catalytic activity (96 %) than the other two in the CO2 transformation reaction with aziridine into oxazolidinones under 0.5 MPa within 4 h. Moreover, Ni3-NH2 can be reused at least ten times without significant catalytic activity loss under mild condition. Importantly, Ni3-NH2 catalyst still can be applicable to the simulating flue gas with 15 % CO2 as carbon source. The mechanism has been further revealed by NMR, FT-IR and DFT calculations, in which the Ni-site and the amino group can synergistically activate the substrate and CO2 molecule. This work has enriched the species of cluster-based MOFs and investigated the influence of characteristic functional groups on the catalytic activity deeply.

Dual Active Sites with Charge‐asymmetry in Organic Semiconductors Promoting C‐C Coupling for Highly Efficient CO2 Photoreduction to Ethanol

Selective CO2 photoreduction into high‐energy‐density and high‐value‐added C2 products is an ideal strategy to achieve carbon neutrality and energy shortage, but it is still highly challenging due to the large energy barrier of the C‐C coupling step and severe exciton annihilation in photocatalysts. Herein, strong and localized charge polarization is successfully induced on the surface of melon‐based organic semiconductors by creating dual active sites with a large charge asymmetry. Confirmed by multiscale characterization and theoretical simulations, such asymmetric charge distribution, originated from the oxygen dopants and nitrogen vacancies over melon‐based organic semiconductors, reduces exciton binding energy and boosts exciton dissociation. The as‐formed charge polarization sites not only donate electrons to CO2 molecules but also accelerate the coupling of asymmetric *CO*CO intermediates for CO2 photoreduction into ethanol by lowering the energy barrier of this process. Consequently, an exceptionally high selectivity of up to 97% for C2H5OH and C2H5OH yield of 0.80 mmol g‐1 h‐1 have been achieved on this dual active sites organic semiconductor. This work, with its potential applicability to a variety of non‐metal multi‐site catalysts, represents a versatile strategy for the development of advanced catalysts tailored for CO2 photoreduction reactions.

Nanoscale Understanding on CO2 Diffusion and Adsorption in Clay Matrix Nanopores: Implications for Carbon Geosequestration.

Carbon capture and storage (CCS) in subsurface reservoirs represents a highly promising and viable strategy for mitigating global carbon emissions. In the context of CCS implementation, it is particularly crucial to understand the complex molecular diffusive and adsorptive behaviors of anthropogenic carbon dioxide (CO2) in the subsurface at the nanoscale. Yet, conventional molecular models typically represent only single-slit pores and overlook the complexity of interconnected nanopores. In this work, finite kaolinite lamellar assemblages with abundant nanopores (r < 2 nm) were used. Molecular dynamics simulations were performed to quantify the spatial distribution correlations, adsorption preference, diffusivity, and residence time of the CO2 molecules in kaolinite nanopores. The movement of the CO2 molecules primarily occurs in the central and proximity regions of the siloxane surfaces, progressing from larger to smaller nanopores. CO2 prefers smaller nanopores over larger ones. The diffusion coefficients increase, while residence times decrease, with the pore size increasing, differing from typical slit-pore models due to the pore shape and interconnectivity. The perspectives in this study, which would be challenging in conventional slit-pore models, will facilitate our comprehension of the CO2 molecular behaviors in the complex subsurface clay sediments for developing quantitative estimation techniques throughout the CCS project durations.

Dual Active Sites with Charge-asymmetry in Organic Semiconductors Promoting C-C Coupling for Highly Efficient CO2 Photoreduction to Ethanol.

Selective CO2 photoreduction into high-energy-density and high-value-added C2 products is an ideal strategy to achieve carbon neutrality and energy shortage, but it is still highly challenging due to the large energy barrier of the C-C coupling step and severe exciton annihilation in photocatalysts. Herein, strong and localized charge polarization is successfully induced on the surface of melon-based organic semiconductors by creating dual active sites with a large charge asymmetry. Confirmed by multiscale characterization and theoretical simulations, such asymmetric charge distribution, originated from the oxygen dopants and nitrogen vacancies over melon-based organic semiconductors, reduces exciton binding energy and boosts exciton dissociation. The as-formed charge polarization sites not only donate electrons to CO2 molecules but also accelerate the coupling of asymmetric *CO*CO intermediates for CO2 photoreduction into ethanol by lowering the energy barrier of this process. Consequently, an exceptionally high selectivity of up to 97% for C2H5OH and C2H5OH yield of 0.80 mmol g-1 h-1 have been achieved on this dual active sites organic semiconductor. This work, with its potential applicability to a variety of non-metal multi-site catalysts, represents a versatile strategy for the development of advanced catalysts tailored for CO2 photoreduction reactions.

Tuning the crystallinity of Cu-based electrocatalysts: Synthesis, structure, and activity towards the CO2 reduction reaction

The rising levels of CO2 have spurred growing concerns for our environment, and curbing CO2 emissions may not be practically viable with the expanding human population. One attractive strategy is the electrochemical CO2 reduction (CO2RR) into value added chemicals but because of the chemical inertness of the CO2 molecule, the electrochemical reduction requires a suitable catalyst. Cu-based catalysts have been largely investigated for CO2RR, however, the difficulty achieving a high selectivity and faradaic efficiency towards specific products, especially hydrocarbons, is still a challenge, alongside the concern over cost, stability and scarcity of the metal catalyst. The present research focuses on tuning the crystallinity of Cu nanoparticles via a green, cost-friendly, and facile method, called the urea glass route. Remarkably, the incorporation of a selected nitrogen-carbon rich source (namely, 4,5 dicyanoimidazole) at low temperatures allow the formation of an oxidized derived amorphous Cu system, whilst a second thermal treatment enables the transformation to crystalline Cu0. We found that the combination of surface Cu0 and Cu1+ (observed via XPS studies) present in our amorphous and crystalline Cu nanoparticles leads to interesting differences in the final catalytic activity when tested under CO2 reaction conditions. The combination of extended X-ray absorption fine structure (EXAFS) experiments and molecular dynamics simulations provides compelling evidence for the amorphous and metallic nature of Cu nanoparticles.

Compact and high excitation molecular clumps in the extended ultraviolet disk of M83

The extended ultraviolet (XUV) disks of nearby galaxies show ongoing massive-star formation, but their parental molecular clouds remain mostly undetected despite searches in CO(1-0) and CO(2-1). The recent detection of 23 clouds in the higher excitation transition CO(3-2) within the XUV disk of M83 thus requires an explanation. We test the hypothesis introduced to explain the non-detections and recent detection simultaneously: The clouds in XUV disks have a clump-envelope structure similar to those in Galactic star-forming clouds, having dense star-forming clumps (or concentrations of multiple clumps) at their centers, which predominantly contribute to the CO(3-2) emission and are surrounded by less dense envelopes, where CO molecules are photo-dissociated due to the low-metallicity environment there. We utilized new high-resolution ALMA CO(3-2) observations of a subset (11) of the 23 clouds in the XUV disk of M83. We confirm the compactness of the CO(3-2)-emitting dense clumps (or their concentrations), finding clump diameters below the spatial resolution of 6-9 pc. This is similar to the size of the dense gas region in the Orion A molecular cloud, a local star-forming cloud with massive-star formation. The dense star-forming clumps are common between normal and XUV disks. This may also indicate that once the cloud structure is set, the process of star formation is governed by the cloud's internal physics rather than by external triggers. This simple model explains the current observations of clouds with ongoing massive-star formation, although it may require some adjustment, for example including the effect of cloud evolution, to describe star formation in molecular clouds more generally.

Self-Inhibition Phenomena in Cu3Pt Oxidation by CO2.

This study investigates the oxidation behavior of Cu3Pt(100) in CO2 using a combination of ambient-pressure X-ray photoelectron spectroscopy, mass spectroscopy, and density functional theory modeling. Our in situ measurements reveal the simultaneous oxidation and reduction of Cu2O due to the opposing effects of atomic oxygen and CO generated from dissociative CO2 adsorption, leading to a dynamic equilibrium state of simultaneously occurring redox reactions. Complementary atomistic calculations elucidate the inhibitory effects of subsurface Pt enrichment and the counteracting roles of CO2 and CO in surface oxidation and reduction. These results provide mechanistic insights into the dissociative pathway of CO2 molecules and dynamic evolution of surface composition and reactivity of Cu-based alloy catalysts in CO2-rich environments, with broader implications for tuning gas-surface reactions by manipulating gas reactants or solid surface composition.

Te2− modulated heterogeneous remodeling of S atoms in ultrathin ZnIn2S4 nanosheets containing S vacancies synergistically enhances CO2 photoreduction

Reconfiguration of in situ heterojunction composites without interfacial resistance by substitution of homologous anions for the formation of gradient work function differences inducing the formation of built-in electric field is an effective strategy to enhance the charge separation efficiency. Herein, Te2−/ZnIn2S4-VS (Te2−/ZIS-VS) in situ heterojunction was synthesized by substitution of Te2− ions for S2− in ultrathin ZIS containing S vacancies, which can significantly promote photogenerated charge separation, surface electron enrichment, and CO2 adsorption/activation. The presence of S vacancies and adjacent Te2−/S2− double anions, the double active sites constructed by defect engineering promote the desorption of *CO molecules while inhibiting the protonation toward *CHO, which was more favorable for selective CO2 photoreduction to CO. The experimental results showed that the CO yield of Te2−/ZIS-VS was significantly increased to 672.1 μmol g−1 h−1 compared with pristine ZIS (54.3 μmol g−1 h−1) and the CO selectivity was close to 83 %. Notably, the life cycle assessment (LCA) of Te2−/Znln2S4 nanosheets with S-vacancy was performed. The evaluation results showed that most of the 17 impact categories showed low overall impact values and were environmentally friendly. Based on the results of this LCA, suggestions were put forward to further optimize the product to reduce carbon emissions.

DFT based investigations on inherent CO2 adsorption and direct dissociation capability of Ti2C and Nb2C mxenes

Transition metal carbide MXenes, specifically Ti2C and Nb2C, have been investigated for their ability to efficiently adsorb and dissociate CO2 using First Principles Calculations based on Density Functional Theory (FPS-DFT). Pure Ti2C and Nb2C sheets were studied with the adsorption of 1 to 4 CO2 molecules, and the results were analyzed for each case. For 4 CO2 molecules adsorbed on Ti2C and Nb2C sheets, the weight percentage (wt%) ratio was found to be 21.39% and 14.33%, respectively. The Density of States (DOS) analysis revealed that, upon CO2 adsorption, the CO2 molecule dissociates into CO and O atoms on the MXene surface. The CO molecule showed no significant hybridization with the host sheet atoms, whereas the O atom exhibited strong hybridization with the MXene surface. Transition State (TS) profiles illustrated the dissociation steps on both Ti2C and Nb2C surfaces. Phonon calculations confirmed the dynamic stability of both pure and CO2 adsorbed MXenes. Molecular Dynamics (MD) simulations conducted at 900 K indicated uniform temperature and Mean Square displacement (MSD) profiles, suggesting the stability of both pure and CO2 adsorbed MXenes at elevated temperatures, as well as uniform CO2 adsorption behavior. The adsorption energies for Ti2C and Nb2C sheets were calculated to be in the range of -1.89 to -2.77eV, suggesting that the adsorption process is favorable, spontaneous, and predominantly involves chemisorption. These findings indicate that Ti2C and Nb2C MXenes, in their intrinsic forms, are promising candidates for CO2 adsorption and dissociation technologies.

Morphology effect of In2O3/Co3O4 on Co–In2O3 interface formation to drive the hydrogenation of CO2 to methanol

In2O3 is loaded onto Co3O4 with diverse morphologies to prepare In2O3/Co3O4 for better understanding of the interaction between metallic Co and In2O3 in CO2 hydrogenation to methanol. After in-depth characterizations, we found that loading In2O3 on platelike Co3O4 (P–Co) can achieve more uniformly dispersed surface hexagonal In2O3 (h-In2O3) and stronger electron transfer between In2O3 and Co3O4 than Co3O4 with other morphologies. Under reaction stabilization, Co3O4 is transformed into metallic Co0, which can promote the reactivity of h-In2O3 to form cubic In2O3 (c-In2O3), accompanied by the formation of Co3InC0.75 carbide. Especially for In2O3/P–Co, stronger interaction between Co0 and c-In2O3 is formed to produce more oxygen vacancies in comparison with other samples owing to the absent of h-In2O3. Furthermore, density functional theory calculation reveals that H2 and CO2 molecules are more easily adsorbed on Co-c-In2O3 interfacial site. As a result, In2O3/P–Co exhibits the best methanol space-time yield of 11.6 mmol · gcat−1 · h−1 and excellent thermal stability for an additional continuous run of 64 h after reaction stabilization.

Constructing the high-efficiency “celluveyor conveyor” transport systems in membranes by IL@ZIF-8 for efficient CO2/CH4 separation

Inspired by the high-efficiency transport systems combined the “conveyor” transport pathways with the “celluveyor” transport pathways, the ionic liquid imide modified ZIF-8 (IL@ZIF-8) was prepared as a filler and incorporated into the self-polymerization-confined Pebax/polyethylene glycol methyl ether acrylate matrix (SPM) to prepare mixed matrix membranes (MMMs) for efficient CO2/CH4 separation. The incorporated IL@ZIF-8 can construct the high-efficiency “celluveyor conveyor” transport systems that consisted of the “celluveyor” transport pathways and the “conveyor” transport pathways, and it played important roles in MMMs. Therein, the “celluveyor” transport pathways can be constructed with the help of CO2 carriers (Zn2+) in oriented and ordered pore channels of IL@ZIF-8, contributing to promoting rapid CO2 transport in multiple direction. IL was uniformly distributed on ZIF-8, and it acted as “binder” between adjacent ZIF-8 in IL@ZIF-8. IL in IL@ZIF-8 can adsorb CO2 molecules as a consequence of its strong chemical affinity for CO2, and the “conveyor” transport pathways can be constructed with the help of CO2 carriers ([Tf2N]-) in IL for rapid CO2 transport between the adjacent ZIF-8, improving CO2 separation performance of MMMs. Consequently, it was possible to enhance the performance of CO2 separation by constructing the high-efficiency “celluveyor conveyor” transport systems in SPM/IL@ZIF-8 MMMs. Therefore, SPM/IL@ZIF-8 MMMs were endowed with the excellent CO2 separation performance. It showed an enhanced permeability for CO2, which increased by 96.9 %, and a better CO2/CH4 selectivity, which improved by 56.6 %, when compared to the performance of the pure SPM membrane. It implied that the constructed high-efficiency “celluveyor conveyor” transport systems in MMMs were a promising strategy for efficient CO2 separation.

Efficient catalysis for acidic methanol oxidation: Exploration of a Low-Platinum quaternary alloy catalyst via a Two-Step method

The quest for platinum-based catalysts with enhanced catalytic efficacy and durability during the methanol oxidation reaction (MOR) has been a focal point in energy conversion science. Traditional platinum-based catalysts are often constrained by their high platinum content, which escalates economic costs and complicates experimental protocols. In this study, we introduce a low-platinum-loaded catalyst synthesized via a two-step method, which incorporates a four-component alloy. This innovative approach significantly reduces platinum content while maintaining superior catalytic performance through precise control over the alloy’s composition and structure. The two-step synthesis methodology streamlines the conventional multi-step processes, enhancing the catalyst preparation’s efficiency and reproducibility. The resulting PtCoSnCu/N-C alloy catalyst exhibits remarkable catalytic activity in methanol solution, with mass activity and specific activity that are 9.73 and 9.75 times higher, respectively, than those of commercial platinum on carbon (Pt/C) catalysts. Notably, the optimized PtCoSnCu/N-C alloy catalyst demonstrates exceptional long-term stability, outperforming Pt/C in aging and extended stability tests. Density functional theory (DFT) calculations elucidate the optimization of the electronic structure and the synergistic effect of surface atoms in the PtCoSnCu/N-C catalyst, which mitigates the adsorption energy of CO molecules and enhances the utilization rate of active sites during the oxidation process. This research presents a paradigm-shifting low-platinum catalyst strategy for methanol fuel cells, establishing a theoretical foundation for catalyst design and optimization.