CO2 Capture Performance Research Articles

Accelerated weathering of construction‐grade limestone for CO2 absorption

AbstractAccelerated weathering of limestone (AWL) process efficiently captures CO2 from point source emissions. However, despite achieving an outstanding capture efficiency of 73.51 %, lab‐grade (LG) limestone with 99.90 % CaCO3 as an absorbent is costly ($2757.70/t), making commercialization of AWL impractical. This work delves into the viability of utilizing construction‐grade (CG) limestone (93.26% purity) for the AWL process facilitated by potable water in an absorption tower for post‐combustion capture. The result shows that CG limestone achieves comparable CO2 capture efficiency of 8.0–74.68% and bicarbonate (Ca(HCO3)2) concentration of 0.63–3.10 mM compared with LG limestone. However, LG limestone has 0.29 mol CO2/mol CaCO3 higher CO2 absorption capacity and a faster absorption rate than CG limestone, indicating a somewhat better CO2 capture performance. Nevertheless, CG limestone offered a more cost‐effective alternative, with a $2735.24 lower cost per ton of CaCO3 and a $2651.63 per ton CO2 lower CO2 capturing cost at the highest carbon capture efficiency (HCCE) condition compared to LG limestone. The kinetic analysis shows that the forward reactions in the AWL process are significantly faster at elevated CO2 concentration, with the mass transfer coefficient affirming that CO2 dissolves faster than CaCO3, in line with prior research. Thus, this work validates that CG limestone‐based AWL achieves comparable CO2 capture performance to that of LG limestone, offering a cost‐efficient alternative. © 2024 Society of Chemical Industry and John Wiley & Sons, Ltd.

Iron Impurity Impairs the CO2 Capture Performance of MgO: Insights from Microscopy and Machine Learning Molecular Dynamics.

Magnesium oxide (MgO) is a promising sorbent for direct air capture (DAC) of carbon dioxide. Iron (Fe) is a common impurity in naturally occurring MgO and minerals used to produce MgO, yet a molecular-scale understanding of Fe-doping effects on carbonation is lacking. Here, we observed reduced carbonation performance in Fe-doped MgO experimentally. The energetics of adsorbing a (bi)carbonate ion on pristine and Fe-doped MgO(001) surfaces were further investigated using ab initio and machine learning potential molecular dynamics coupled with metadynamics simulations. Both pristine and Fe-doped surfaces exhibited a basic (OH-) hydration layer, where the (bi)carbonate ion adsorption is thermodynamically favorable. However, the dissolution of surface Fe had smaller energy barriers and was more favorable than Mg. Leached Fe likely neutralized the near-surface basicity, yielding reduced reactivity on Fe-doped MgO. Our observations offer critical insights for material selection and emphasize the importance of evaluating the geologic origin of earth materials used for DAC.

Thermal analysis and kinetic investigation of using a hybrid adsorption-hydration method to promote CO2 capture

In this work, a hybrid adsorption-hydration method was utilized to promote CO2 capture. The CO2 capture performance in the fixed bed of coal particles was assessed at various water saturations (0 %, 20 %, 40 %, 70 %, and 100 %), 277.15 K, and 3.2 MPa. It was found that gas consumption at 100 % water saturation increased by 45 % compared to that at 0 % water saturation (dry coal particles). Moreover, as the water saturation increased, CO2 capture became dominated by hydrate formation rather than gas adsorption. The thermal analysis for CO2 capture at 0 % and 100 % water saturation detected the exothermic peaks associated with CO2 adsorption and CO2 hydrate formation, as well as the endothermic peaks corresponding to CO2 desorption and CO2 hydrate dissociation. This confirms that CO2 capture in the fixed bed of water-saturated coal particles consists of CO2 adsorption followed by hydrate formation. The morphologies of CO2 hydrate formation in the fixed bed of 100 % water-saturated coal particles were observed, and the mechanism of CO2 capture using the hybrid adsorption-hydration method was illustrated based on the thermal analysis and kinetic investigations. It was also found that after the adsorption-hydration process, the average cumulative pore volume of the coal particles decreased by 14.47 % compared to the original coal particles, and the micropores and mesopores were predominantly affected. Therefore, utilizing the hybrid adsorption-hydration process in a fixed bed of coal particles provides a promising method to enhance CO2 capture.

New insights into the functional group influence on CO2 absorption heat and CO2 equilibrium solubility by piperazine derivatives

Piperazine(PZ) derivatives which have been widely used in CO2 capture technology exhibit stable physicochemical properties, such as resistance to thermal degradation and low regeneration energy consumption. Both two parameters of CO2 absorbents, low CO2 absorption heat(ΔHabs) and large CO2 equilibrium solubility(αe), are important to CO2 capture performance. However, the influence of functional group types of PZ derivatives on their CO2 capture performance remained unclear. This research aimed to study the functional group influence on the ΔHabs and αe by PZ derivatives with two amines using experimental and quantum chemical methods. The results indicated that PZ derivatives with the ethyl side chain had larger ΔHabs and αe than those with the methyl side chain. The presence of the hydroxy group in PZ derivatives reduced the ΔHabs and the αe. The presence of cyclic methyl side chains on the N atom of PZ derivatives decreased the ΔHabs and increased αe at the same time. The findings show that PZ derivatives with cyclic methyl side chains, steric hindrance effect, and no hydroxy group are favorable for CO2 capture. Among the eight PZ derivatives, TEDA with lower ΔHabs(48.99 kJ/mol) and higher αe(0.917 mol CO2/mol amine) is an excellent absorbent. The results of this study are very important for screening efficient and low-energy consumption absorbents for CO2 capture.

Preparation of “dry water”-type liquid marbles with enhanced mechanical stability and CO2 capture performance

Liquid marbles(LMs) are formed by encapsulating liquid with hydrophobic particles showed potential application in capturing CO2. However, conventional LMs are mostly millimeter scale and easily deformed by extrusion. This study aimed to enhance the mechanical stability by controlling the particle size to prepare “dry water” type LMs (DWLMs). The N-methyldiethanolamine (MDEA) solution was used as the core in constructing DWLMs, and SiO2/graphene(GPE) was used as the shell material. The incorporation of GPE can endow DWLMs with photothermal conversion properties, with a particle size distribution around 100 ∼ 250 μm occupying the largest volume fraction. These DWLMs exhibited good flow ability and mechanical stability. Moreover, the effects of MDEA concentration, and content of SiO2/ GPE on the preparation of DWLMs were investigated. Under an illumination intensity of 1 × 106 Lux, the temperature of DWLMs reached above 95 °C. Subsequently, the absorption performance was examined by a fixed-bed absorption tower, and it was found that decreasing the droplet size can increase the gas–liquid mass transfer area to reduce the mass transfer resistance. The height of the fixed bed constructed by DWLMs was higher than 7 cm, and the bottom particles can still maintain stability without agglomeration and blocking the supporting mesh. The breakthrough point (t0.5 and t0.95) of large-DWLMs (L-DWLMs) were greater than that of tiny-DWLMs (T-DWLMs). The absorption kinetics have validated that chemisorption is the primary mode of CO2 absorption. In desorption process, the results showed that the desorption of CO2 was realized by photothermic desorption, and the desorbed DWLMs were regenerated and recycled, which could prevent the corrosion of the device as well as utilize the energy provided by the sunlight.

Efficient integration of calcium looping with methane Bi-reforming using Pd-enhanced Ni-CaO dual functional nanomaterials

Integration technology of methane bi-reforming (BRM; a combination of methane steam and dry reforming) with calcium looping (CaL-BRM) offered a novel solution to reduce CO2 emission, enabling direct capture and conversion of low-concentration CO2 from sources into value-added products (H2, syngas) within the same reactor. In this study, Ni-CaO-based dual-functional material (DFM), with a small quantity of palladium in the nanostructure, was developed via a continuous two-stage aerosol process and employed in the CaL-BRM. Experimental results demonstrate that Pd-Ni-CaO exhibited high activity and cyclic stability over multiple cycles, maintaining effective CO2 capture (12.0 mmolCO2/gCaO) and BRM performance (>98 % CO2 conversion; H2/CO = 2) at a relatively low temperature (600 °C). Density functional theory calculations reveal that the presence of Pd lowered the activation energy of CH* dissociation, the rate-determining step, from 1.14 to 0.67 eV. The higher adsorption energy (−0.87 eV) of H2O on the Ni-Pd surface and the lower energy barrier (0.62 eV) for subsequent dissociation contributed to the promising catalytic performance in the presence of steam. These findings underscore the significance of utilizing appropriate DFM and demonstrate the potential of CaL-BRM for efficient integrated carbon capture and utilization.

The effects of counter ion on CO2 capture performance of amino acid salt solutions for direct air capture applications

Direct CO2 capture from the atmosphere has received growing attention driven by the imperative of achieving global net-zero emission targets. Amino acid salt solutions are promising candidates for liquid-based direct air capture processes. Utilised as a neutralized salt by reacting initially with hydroxides, it has been speculated that their performance may vary with the type of counter ion present in the solution. This work investigates the influence of counter ions, potassium, sodium, and lithium, of amino acid salt solutions on the physical properties, the CO2 absorption capacities, and the CO2 absorption kinetics under atmospheric CO2 concentration levels. The potassium-containing amino acid solutions exhibited significantly lower viscosities and mildly elevated densities compared to sodium- and lithium-containing ones. At 25 °C, the potassium-prolinate solution demonstrated the highest viscosity (8.5 mPa⋅s), whereas K-glycinate exhibited the lowest viscosity (2.5 mPa⋅s). Additionally, potassium-based solutions consistently displayed the highest CO2 mass transfer coefficients, followed by sodium- and lithium-containing ones. The CO2 mass transfer coefficient was highest for potassium-prolinate (2.99 mmol m−2⋅s−1⋅kPa−1) with the lowest rate observed for potassium-β-alaninate (1.68 mmol m−2⋅s−1⋅kPa−1). Interestingly, the type of counter ion had minimal impact on the CO2 absorption capacity, with potassium-based solutions exhibiting only a slightly elevated capacity compared to sodium- and lithium-based solutions. Specifically, potassium-lysinate displayed the highest CO2 absorption capacity (0.7 mol CO2 /mol amine), while potassium-β-alaninate showed the lowest (0.65 mol CO2/mol amine). It should be noted that all lithium-based solutions of all amino acids formed precipitates during CO2 absorption. From a practical and operational perspective, these findings suggest that the potassium salt solution of amino acids would be the optimal choice for direct air capture applications due to their enhanced solubility and CO2 mass transfer rates compared to the corresponding sodium and lithium counter ion salt solutions.

LiNaCO3‐Containing Porous Carbon Composites for CO2 capture

AbstractIn this study, LiNaCO3‐ and (Li‐Na‐K)2CO3‐based porous carbon composites were synthesized from terephthalic acid, lithium hydroxide, sodium hydroxide, and potassium hydroxide at different calcination temperatures. These composite materials were characterized with X‐Ray diffraction, scanning electron microscopy, and nitrogen adsorption and desorption. According to their CO2 capture performance measured, LiNaC‐700 °C had the largest CO2 adsorption capacity of 66 mg CO2 g−1, while the CO2 capture capacity of other materials doped with three metal ions was only up to 8.57 mg CO2 g−1. Additionally, the CO2 adsorption capacity of each adsorbent was significantly higher than the N2 adsorption capacity, showing their high CO2 adsorption selectivity. Lithium‐containing carbonate‐based porous carbon materials (LiNaCO3‐ and (Li‐Na‐K)2CO3‐based porous carbon could effectively capture CO2 with excellent reproducibility.

Electronic interaction between d electron-poor and d electron-rich transition metal ions promoted the CO2 capture performance of calcium-based adsorbent

The investigation of intrinsic principles for the more precise design CaO adsorbent with excellent CO2 capture performance by doping metal oxides is of great significance, but has not yet been explored. Herein, we address the critical challenge by systematical evaluation on a series of magnetic bimetallic oxides doped calcium-based adsorbents from the perspective of electronic interaction between d electron-poor and d electron-rich transition metal ions promoting the CO2 capture performance. The Mn, Co, Mo and Ni metal ions with varied d-electron numbers are doped into calcium-based adsorbent, and the results show that the introduction of magnetic bimetallic oxides with d electron-poor and d electron-rich transition metal ions into CaO at the same time can significantly promote the stability of CO2 capture. Taking the (Mn-Co)-codoped samples as an example, the relationship of d electron-poor and d electron-rich transition metal ions synergistic interaction and promoted CO2 adsorption performance is elucidated. The loose flake nanostructures favor the diffusion of CO2 inside the particles, and the uniform distribution of each component effectively ensures the double-exchange interactions. The generation of more oxygen vacancies significantly improves the CO2 affinity for the calcium-based sample. Furthermore, the results of kinetic analysis reveal that the synergistic interaction can reduce the apparent activation energy of carbonation reaction. These insights into the systematical regulation of the double-exchange interaction are expected to provide guidance for the relatively more precise design of the calcium-based adsorbent with high performance of CO2 adsorption.

Investigation on CO2 capture performance of low-viscosity diamine non-aqueous absorbents with N-methyldiethanolamine regulation

In recent years, non-aqueous absorbents have attracted increasing attention due to their ability of significantly reducing sensible and latent heats in regeneration processes compared to conventional organic amine aqueous solution. But high viscosity of non-aqueous absorbents after CO2 absorption saturation became an obstacle to their industrial application. Here, a novel low-viscosity diamine non-aqueous absorbent for high-efficiency CO2 capture was proposed, in which N-methyldiethanolamine (MDEA) with steric hindrance effect was introduced as a regulator and dimethyl sulfoxide (DMSO) as a cosolvent. The effects of MDEA on CO2 capture performance of various non-aqueous absorbents and its regulation mechanism on CO2 absorbent viscosity were investigated systematically. Experimental results showed that when 25 wt% 2-(2-aminoethylamino)ethanol (AEEA) was screened as main CO2 absorption component, AEEA/MDEA/DMSO non-aqueous absorbent exhibited a high CO2 absorption capacity of 2.55 mol/kg and a fast CO2 absorption rate. Based on further mass fraction optimisation, it was found that the lowest viscosity of non-aqueous absorbents after CO2 absorption was 13.12 mPa s and the highest CO2 regeneration reached 93.5 % with AEEA and MDEA were 17.5 wt% and 12.5 wt%, respectively. 13C NMR tests showed that two characteristic peaks of carboxylated carbon appeared in CO2 products, which indicated that both amino groups on AEEA molecule were involved in CO2 absorption reaction. DFT calculations indicated that hydrogen bonding strength between MDEA and CO2 products was relatively lower than that of AEEA and CO2 products, which favored reducing absorbent saturation viscosity significantly. Thermodynamic analysis revealed that total regeneration energy consumption for 17.5 wt% AEEA/12.5 wt% MDEA/70 wt% DMSO non-aqueous absorbent was 1.72 GJ/t CO2, which was 53 % lower than that of MEA aqueous solution.

Anomalous enhancement of humid CO2 capture by local surface bound water in polar carbon nanopores

Removal of confined space carbon dioxide (CO2) that is in low concentration and with coexisting water is necessary but challenging by physical adsorption method. To make the removal process effective, rendering the nanopore surface hydrophobic to resist water is the popular way. Instead of preventing water from occupying the nanopores, in this work, we propose to utilize the guest water for the spatially selective formation of local surface bound water and further induce the preferential CO2 capture. We observe an anomalous enhancement of CO2 capture performance under humid conditions over carbon nanopores with spatially selective polar sites. It is evidenced that the surface bound water is formed at non-CO2-selective areas of polar carbon nanopores, thus creating additional CO2 trapping sites. This work may inspire the design of environment tolerable materials for molecular separation and purification under harsh conditions.

CO2 gas-liquid equilibrium study and machine learning analysis in MEA-DMEA blended amine solutions

The combination of primary and tertiary amines represents a promising approach to improve sorbent performance in CO2 capture by enhancing absorption efficiency and reducing regeneration energy. This study focuses on investigating the absorption performance of binary mixtures of ethanolamine (MEA) and N,N-dimethylethanolamine (DMEA) at temperatures between 298–323 K and CO2 partial pressures between 5–60 kPa. The species generated during the absorption were analyzed using 13C NMR spectroscopy, to clarify the intricate role of MEA and DMEA in the capture process. A developed excess property model for MEA-DMEA, based on excess CO2 loading, predicted equilibrium CO2 solubility data with an average absolute relative deviation (AARD) of 1.6 %. Additionally, the machine learning models XGBoost, RBFNN, and SVR were applied, providing AARD values between 0.86 % and 1.28 %, demonstrating strong agreement between experimental and predicted outcomes. These comprehensive findings enhance our understanding of mixed amines’ mechanisms and practical applications, contributing to ongoing research development.

Evaluation of calcium looping CO2 capture and thermochemical energy storage performances of different stabilizers promoted CaO-based composites derived from solid wastes

Calcium looping is considered as an important high-temperature cyclic CO2 capture and concentrated solar energy storage technology. However, the dramatic inactivation of CaO over multiple carbonation-calcination cycles has seriously restricted their practical applications. In this study, a series of metal oxide (i.e. TiO2, MgO, Al2O3 and ZrO2)-stabilized CaO-based materials with high cyclic stability derived from carbide slag were synthesized via a facile and cost-effective approach for simultaneously enhanced CO2 capture and thermochemical energy storage (TCES). The results suggest that CCS-H-TiO2 exhibits high initial CO2 uptake of 0.41 gCO2/gsorbent, superior cyclic stability with an average attenuation of 1.71 %/cycle and remarkably stable energy storage density. CCS-H-Al2O3 shows the best stability with lowest attenuation rate of 9.6 %. Except for CCS-H-MgO, the stabilizers reacted with active calcium to form new phases and used as physical “barrier” and high-TT skeleton to offset the sintering stress, retain the microporous structures, hinder the excessive agglomeration and alleviate sintering.

Solar-driven calcination of clays for sustainable zeolite production: CO2 capture performance at ambient conditions

This study presents the environmentally sustainable synthesis of zeolites from solar-calcined kaolin and halloysite, emphasizing their application in CO2 capture due to their distinctive porous structures and chemical attributes. Expanding upon prior research that utilized solar energy for kaolin calcination, we now explore halloysite as an alternative clay mineral for zeolite production and CO2 capture. Employing a solar simulator, halloysite was calcined at temperatures ranging from 700 to 1000 °C, resulting in the synthesis of zeolites 4A and 13X via hydrothermal methods. The synthesized zeolites were characterized using X-ray diffraction (XRD), low angle XRD (LA-XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FE-SEM), and Brunauer–Emmett–Teller (BET) surface area measurements. Notably, the presence of Al-Si spinel, which crystallizes at elevated solar calcination temperatures, persisted within the zeolite 13X matrix, inducing a secondary mesoporous phase. The observed hysteresis in 13X samples, rather than confirming the mesoporous character of zeolite 13X, indicates a tandem effect of mesoporous Al-Si spinel with microporous zeolite 13X, exemplifying systems known as micro/mesoporous zeolitic composites (MZCs). The correlation obtained between the interplanar distances calculated from LA-XRD and pore size distributions acquired from the BJH desorption branches highlights LA-XRD as an alternative analysis method for assessing mesoporosity. While the microporosity of Al-Si spinel possessing 13X samples positively correlates with CO2 capture performance, mesoporosity appears to have minimal impact. Among the zeolites synthesized using solar energy, zeolite 4A (LTA) demonstrates superior CO2 capture capability, achieving an adsorption capacity of 2.15 mmol/g at 25 °C and 1 bar. This study highlights the potential of solar energy in producing eco-friendly zeolites from kaolin and halloysite for improved CO2 capture, advancing sustainable environmental solutions.

Research on CO2 capture performance and reaction mechanism using a novel low energy consumption and high cyclic performance absorbent for onboard application

High desorption energy consumption and low cyclic loading are critical issues limiting the application of onboard carbon capture (OCC) systems. In this study, a tetraethylenepentamine (TEPA) and 2–amino–2–methyl–1–propanol (AMP) mixed amine solvent with low desorption energy consumption and high CO2 cyclic loading, suitable for the operational environment of OCC systems, has been proposed. Detailed research was conducted on the capture performance and mechanism of the TEPA + AMP mixed amine solvent. The 0.25M TEPA+0.75M AMP mixed amine solvent exhibited the best performance, with an 86.5% increase in CO2 loading, a 214% increase in single–cycle CO2 loading, a 236% increase in CO2 loading after four cycles compared to monoethanolamine (MEA), and a 20.76% reduction in desorption energy consumption. In addition, to address the challenge of applying polyamine mixed solutions in the simulation studies of OCC systems, the capture mechanism was analyzed using density functional theory (DFT) calculations and nuclear magnetic resonance (NMR) characterization. The results indicated that increasing AMP promoted HCO3– formation in the TEPA + AMP mixed amine solvent. Since HCO3– decomposed more easily than carbamate, it reduced desorption energy consumption. However, an excess of AMP inhibited the absorption rate of TEPA, affecting the absorption capacity. Increasing the concentration of TEPA enhanced the amine concentration in the absorbent and improved the absorption performance. Nevertheless, excessive TEPA caused AMP to participate only in deprotonation reactions, which was not conducive to reducing desorption energy consumption.

Metal Ions Modified Azo‐Linked Porous Polymers for High Performance CO2 Capture

AbstractPorous polymer show great potential for CO2 capture owing to its high specific surface area, adjustable porous structure and chemical structure. Herein, a novel CO2 adsorption materials ALP−M (M: Cu2+, Mg2+, Ni2+) were prepared through coordination between azo‐linked porous polymer (ALP) synthesized by oxidative coupling polymerization of tris(4‐aminophenyl)amine and metal ions. The structures and morphology of as‐prepared materials were demonstrated by FT‐IR, XRD, XPS, BET and SEM, the CO2 capture performance and mechanism of ALP−M were also investigated through static adsorption and column adsorption experments, the results show that metal ions can enhance the CO2 adsorption and desorption performance of ALPs by coordination adsorption. ALP−M showed a highest static CO2 adsorption capacity of 2.67 mmol g−1 at 273 K (1 bar), which is 35.5 % higher than that of ALP. The metal ions served as Lewis acid sites can enhance the affinity of adsorbent for CO2. In column adsorption experiments, the ALP−M showed a higher saturated adsorption capacity 4.99 mmol g−1 at 273 K (1 bar) than that of static adsorption, and excellent cycling stability after 500 adsorption and desorption cycles, the adsorption capacity retention rate of ALP−M for CO2 can reach 98 %.

CFD modeling of CO2 fixation by microalgae cultivated in a lab scale photobioreactor

The green microalga Chlorella vulgaris has been studied for efficient fixation of carbon dioxide, CO2, from elevated concentrations of in-feed gas flows. In this work, a Computational Fluid Dynamics (CFD) model for algae cultivation including the dependence on CO2 concentration in liquid has been derived based on cultivation experiments of Chlorella vulgaris. The experiments were performed in a laboratory scale cylindrical stirred tank reactor with a range of enriched CO2 concentrations in-feed (0.04–50 %). The model provided by Béchet et al. (2015) for algae cultivation considering dependence on local light, algae concentration and temperature has been implemented for CFD and modified for comprising CO2 dependence. The model has been verified with experimental results for the algae productivity showing the proper trends for dissolved CO2 concentrations and algae concentrations. Thus, the developed CFD model can serve as a tool for evaluating photobioreactor performance for CO2 capture

Continuous flow synthesis of MOF UTSA-16(Zn), mixed-metal and magnetic composites for CO2 capture – toward scalable manufacture

UTSA-16(Zn) is a zinc and citrate-based metal-organic framework (MOF) which has shown highly promising performance for CO2 capture. However, the transition of this MOF to industrial application has been hindered as a scalable synthesis method has not yet been reported. Herein we report the first scalable continuous flow synthesis of UTSA-16(Zn), demonstrating a production rate of 173 g/h, which is a 77-fold increase compared to previously reported batch methods. Sustainability of the synthesis was maximised using low-cost non-toxic reagents and a low-energy flow reactor operating at atmospheric pressure. Chemical (reactant ratios, Zn/Mg mixed-metal) and process parameters (solvent ratio, flow rate, temperature) were optimised to continuously produce UTSA-16(Zn) which also demonstrated a high CO2 adsorption capacity up to 3.8 mmol/g and conversion yield of up to 66 %. Pristine MOFs are typically thermally insulating, thus thermal regeneration is challenging. To overcome this limitation, magnetic nanoparticles can be embedded within the MOF. This enables fast and energy efficient regeneration through magnetic induction heating. Here, citrate-coated Fe3O4 magnetic nanoparticles (MNP-CA) were successfully incorporated into the flow synthesis process of UTSA-16(Zn) to form UTSA-16(Zn)@MNP-CA magnetic framework composites (MFCs), representing the highest production rate reported of any MFC to date (152 g/h c.f. 13 g/h for MgFe2O4@UiO-66-NH2). UTSA-16(Zn)@MNP-CA MFCs demonstrate rapid heating under a magnetic field (26–150 °C in 60 s). The flow method developed herein is also widely applicable for scalable manufacture of other MOFs and MFCs, enabling their broader transition towards industrial applications.

Modulation of p-Block Electron Orbits in Metal-Organic Frameworks for CO2 Capture and Electrochemical Reduction.

Developing catalysts with excellent CO2 capture capability and electrochemical CO2 reduction reaction (CO2RR) at a wide potential range simultaneously is significant but remains a formidable challenge. Here, two novel InMg defective trinuclear cluster-based MOFs (SNNU-41 and SNNU-42) with abundant p-block unsaturated coordinated sites were reported and exhibited good CO2 capture and CO2RR performance simultaneously. Due to the suitable micropores, SNNU-41 showed higher CO2 capture ability at different adsorption pressure conditions. On account of the rigid framework and the closer p band center to Fermi level, SNNU-42 accelerated the conversion of CO2 molecule to C1 efficiency. Notably, via adjusting the ratio of p-block metal (In) in the SNNU-42 framework, the performance of the CO2RR was promoted drastically. SNNU-42 with the InMg (1:1.8) mixed cluster delivered an excellent Faradaic efficiency of 91.3% for C1 products and high selectivity of 72.0% for HCOOH at -2.5 V (vs Ag/Ag+) with a total current density of 77.2 mA cm-2. This work provides a possibility for efficient CO2 capture and CO2RR electrocatalysts through the modulation of electronic structures and composition in MOFs.

Developing slurry based on immobilized and aqueous [MEACl][EDA] for CO2 capture

The urgent need to mitigate climate change and reduce greenhouse gas emissions has underscored the importance of developing effective CO2 capture technologies. In this study, a novel strategy was proposed and developed, where adding cosolvent and immobilizing deep eutectic solvent (DES) were combined to enhance the performance from capacity to rate. To this end, [MEACl][EDA] (1:5) was chosen as the DES, H2O was used as the cosolvent, and silica was selected as the substrate to immobilize the DES; the effects of the DES immobilization amount and the concentration of the immobilized DES particles in the aqueous system as well as temperature on the viscosity and CO2 capture performance were investigated systematically. Compared to the aqueous DES, the slurry exhibited higher CO2 uptake and improved kinetics, comparable viscosity before CO2 capture, and slightly high viscosity after CO2 capture, where the best sample (3 wt% of (5 wt% DES@silica) in 40 wt% aqueous DES) showed a capacity of 24.93 wt% at the room temperature (22 ℃) and viscosities of 7.32 and 21.82 mPa·s before and after CO2 capture. Also, the CO2 capture rate of the slurry reached 1.4 mol CO2/(kg sorbent·min) after 2 min at 22 ℃, which was higher than the aqueous DES without immobilized DES (1.24 mol CO2/(kg sorbent·min) under the same condition). The prepared slurries showed high stability (over one month) and high regeneration (∼91 % CO2 capture recovery after 5 cycles).