Enhanced CO2 Adsorption Research Articles

Enhancing CO2 adsorption performance of cold oxygen plasma-treated almond shell-derived activated carbons through ionic liquid incorporation

To enhance the CO2 adsorption of almond shell-derived activated carbon (AC) samples treated with cold oxygen plasma, the samples were impregnated with cholinium-amino acid ionic liquids ([Cho][AA] ILs) using the vacuum-assisted impregnation method. The physicochemical and textural properties of the resulting composites (ILs@AC) were characterized using various techniques, including Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray (EDX) spectroscopy, and Brunauer-Emmett-Teller (BET) surface area measurement. The CO2 adsorption performance of the samples was evaluated using a quartz crystal microbalance (QCM) over a temperature range of 288.15–308.15 K and gas pressures up to 1 bar. The IL@AC composite materials exhibited notably improved CO2 adsorption capacities compared to pristine AC. The CO2 adsorption isotherms onto the IL@AC composite samples closely conformed to the Langmuir isotherm model, indicating the dominant involvement of strong intermolecular interactions, particularly driven by amine functionalities. Meanwhile, the results revealed that [Cho][His]@AC showed lowered CO2 adsorption capacity compared to [Cho][Pro]@AC and [Cho][Gln]@AC. Among the studied ionic liquids, [Cho][Pro]@AC showed the highest absorption capacity (2.332 mmol·g−1 at 288 K and 1 bar). This was due to the obstruction of internal pores within the AC structure caused by excessive amine incorporation into its porous framework. In the meantime, for a deeper insight into the impregnation process of ILs onto the AC surfaces and their potential interactions with CO2 molecules, we conducted density-functional theory (DFT) calculations using the ωB97XD/6-31 + G(d,p) method. The calculated interaction energies, ranging from − 1.19 to − 1.44 eV, along with calculated quantum chemical descriptors, indicated a notable stabilization of IL species on the AC surfaces, with high affinity toward CO2 molecules.

Impact of aminopropyl units on physisorption in mesostructured silica is larger for CH4 than CO2 and depends on pore curvature

Mesoporous silica-based materials attract great interest for diverse applications, including capture, storage, and catalysis due to their large surface area, uniform pore size distribution, and customizable surface. The regular 2D hexagonal pore symmetry of MCM-41 makes it an ideal model. Amine groups are introduced to enhance CO2 adsorption, but the interplay of factors influencing overall performance, including pore size, remains unclear. This computational study explores the physisorption of CO2 and CH4, shedding light on the microscopic details underlying adsorption capacity and selectivity. Three aminopropyl-functionalized MCM-41 models with different pore size are compared through Grand Canonical Monte Carlo and Molecular Dynamics simulations. Aminopropyl chains affect CO2 adsorption, but its affinity for the preserved silanol groups is larger. In addition, the competitive interaction between amine and silanol groups emerged, and it is pore curvature dependent. Surprisingly, CH4 physisorption is influenced even more by surface functionalization. Results show a non-monotonic trend as a function of pore size. Local density of the alkyl chains plays the major role. Overall, the intermediate pore size demonstrates the best performance, thanks to the balance among the various effects. The study emphasizes the importance of understanding the interplay between material texture and gas interactions to optimize adsorption performance.

Combined experimental and grand canonical Monte Carlo simulation study of CO2 capture in nitrogen and sulfur co-doped biochar derived from biowaste: Cost analysis, kinetics, and equilibrium

Nitrogen (N) and sulfur (S) co-doped biochar was produced from an agricultural waste. Heat treatment was combined with the use of dopants including thiourea, CO2, and air. The results show that the modified N and S co-doped biochar with the use of CO2 gas agent at 1123 K for 2 hr in the modification process, had the highest CO2 adsorption capacity of 4.36 and 3.05 mmol/g at 273 and 298 K at 1 bar among others in literature even it had lower surface area or pore volume. This is due to the containing of N and S on the solid surface and superior pore size of 1.0 nm. Moreover, the modified biochar had superior kinetics and CO2/N2 selectivity and was more economical than its unmodified biochar. To support experimental observation and better understand individual characteristics of functionalized carbons, a grand canonical Monte Carlo simulation was carried out to systematically illustrate the effect of N and S functional groups, pore size and pore volume on CO2 adsorption. The surface chemistry was the minor factor and played the key role in CO2 adsorption capacity at low pressures until it became saturated by adsorbate molecules at 0.3 bar. S was stronger than N for enhanced CO2 adsorption capacity. Whereas the pore size was the major factor in both low and moderate pressures (< 23 bar). The optimum pore size was found in a range of 0.66⎼4.0 nm which was pressure-dependent. The pore volume became the main factor at higher pressures (> 23 bar).

Eutectic molten salt assisted fabrication of microporous biochar for greenhouse gases adsorption

The utilization of eutectic molten salt technology has emerged as a prominent area of investigation aimed at fabricating a novel carbon material sorbent based on biomass wastes. The adsorption mechanism on CO2 adsorption remains inadequately elucidated as well. Herein, the biochar fabrication process involving eutectic molten salt method at intermediate-low temperature of 550 °C was successfully achieved and investigated in detail. The impacts of molten salt composition, monomer salt’s anion and cation, and pyrolysis parameters were firstly studied on the resulting microporous biochar of 1.8 nm pore diameter and 975 m2/g surface area. The optimized conditions are 550 °C, 15 °C min−1 ramp rate, 120 min holding time, Na+ cation, NO3– anion, and ternary salt KCl/NaNO3/Na2SO4 of 32.5/30.4/37.1. The efficient adsorbent exhibited abundant micropores and a substantial specific surface area, leading to enhanced CO2 adsorption quantity of 3.75 mmol/g (the calculated capacity is up to 4.54 mmol/g) at pressure state of 1.6 MPa. Investigation into key factors, adsorption kinetics, and adsorption isotherm revealed that CO2 capture by optimal adsorbent predominantly stemmed from micropore filling, van der Waals forces, hydrogen bonds, and Lewis acid-base interactions. This research contributes novel insights into the utilization of biochar adsorbents for CO2 capture in the realm of industry.

Examination of the use of binderless zeolite blend as backfill materials to enhance CO2 adsorption in coal mine working face

The release and accumulation of CO2 in the working face of the coal mine is a major safety concern and requires an effective means to avoid the incidence of the mine. This present study therefore sought to develop a self-CO2 adsorbing backfill (SCAB) material to remove CO2 from the working environment, and simultaneously mitigate the movements of the surrounding rock layers. SCAB was formulated using coal mine solid waste activated with an alkali activator, and binderless 4 A zeolite was embedded in the backfill body. The total CO2 adsorption capacity was investigated using a CO2 flow-through method under ambient pressure and temperature conditions. The adsorption plateau was found in stages II and III respecting the predetermined curing time and zeolite contents. The maximum adsorption capacity was 143.8 mg-CO2/g-SCAB, resulting in an increase of up to 82 % in UCS compared to reference samples. The underlying mechanism was discovered in morphological analyses.1) The well distribution of zeolite in the SCAB body provided as diffusive pathways and adsorption sites for CO2 after standard curing. 2) The adsorbed CO2 underwent a desorption stage when the CO2 concentration decreased and reacted to the cementitious matrix of the SCAB body. 3) More CaCO3 crystals were generated and filled in the micro spaces of the SCAB body, which contributed to an increase in compressive strength. This study developed an effective approach to remove CO2 gas from the working face of the coal mine during backfilling. Adsorbed CO2 improved the strength of the material, provided as a novel multi-function backfill mining for sustainable green coal mining technology.

Understanding the influences and mechanism of water vapor on CO2 capture by high-temperature Li4SiO4 sorbents

Li4SiO4 sorbent attracts wide attention due to its high and stable CO2 adsorption. However, the process of CO2 capture is significantly affected by various impurities under the circumstance of industrial applications, and water vapor is one such impurity that needs to be well studied. Herein, we aim to evaluate the effect of water vapor on physicochemical characteristics of Li4SiO4-based sorbents during cyclic CO2 adsorption and desorption and to understand the action mechanism of H2O molecules on CO2 adsorption by Li4SiO4. Reaction tests show that water vapor can significantly enhance CO2 adsorption performance of sorbents, but the promotion effect varies with the different presence of water vapor during reactions. Material characterization and DFT calculation reveal that although the presence of water vapor leads to deterioration of internal pore structure of the sorbent, H2O molecule will form OH– on the surface of Li4SiO4 and further react with CO2 to generate HCO3–, thus the adsorption energy with water vapor presenting is increased with an observation of promoted CO2 adsorption.

Unveiling the role of silicon in boosting electrochemical carbon dioxide reduction via carbon nanotubes@bismuth silicates

Electrochemical CO2 reduction reaction (CO2RR) is one of the most attractive measures to achieve the carbon neutral goal by converting CO2 into high-value chemicals such as formate. Si in Bi silicates is promising to enhance CO2 adsorption and activation due to its strong oxygenophilicity. Whereas, its role in boosting CO2RR via the cheap Bi-based catalysts is still not clear. Herein, we design CNT@Bi silicates catalyst, demonstrating the highest FEHCOOH of 96.3 % at −0.9 V vs. reversible hydrogen electrode with good stability. Through X-ray photoelectron spectroscopy (XPS), in-situ Attenuated Total Reflectance-Fourier Transform Infrared (In-situ ATR-SEIRAS) experiments, and Density Functional Theory (DFT) calculations, the role of Si in Bi silicates was unveiled: tuning the electronic structure of Bi, weakening the Bi-O bond, and strengthening electron transfer from Bi to CO2, thereby promoting the generation of CO2*− and *OCHO intermediates. Additionally, carbon nanotubes (CNTs) promote not only the conductivity but also the generation of abundant oxygen vacancies in CNT@Bi silicates evidenced by the electron transfer from CNT to Bi silicates from XPS results. Further, the CNT@Bi silicates endows it with the highest electrochemical activation area. These findings suggest the effectiveness of Si in Bi silicates and structure tuning to design highly selective CO2RR catalyst for HCOOH production.

Negative Reaction Order for CO during CO2 Electroreduction on Au.

The potential-dependent negative fractional reaction orders with respect to the CO partial pressures were measured for CO2 electroreduction (CO2R) on Au under mass-transfer-controlled conditions using a rotating ring-disk electrode setup. At high overpotentials, the CO reaction order approaches -1 due to enhanced CO adsorption on Au, which is supported by kinetic analysis and density functional theory (DFT) simulations. This work illustrates that the CO site-blocking effect cannot be ignored, even on a weak CO-binding metal such as Au in the electrochemical environment. The CO site-blocking effect can greatly hamper the activity and the selectivity of the CO2R to CO. This observation enriches the current mechanistic understanding of the CO2R and could have significant implications not only in the theoretical modeling of the CO2R but also in the evaluation of intrinsic CO2R activity at practical current density and high conversion conditions.

CO2 adsorption on a K-promoted MgO surface: A DFT theoretical study

The primary cause of global warming is the emission of greenhouse gases such as CO2. So reducing CO2 emissions is vital. This paper investigates the impact of the atom K as a promoter of MgO on the CO2 adsorption properties using the DFT theoretical computational method. By analyzing the adsorption energy, bader charge as well as the density of states and COHP, it was found that K-promoting the MgO (100) surface resulted in a redistribution of charge on the MgO surface and enhanced CO2 adsorption compared to the pure MgO surface. The presence of K atoms causes orbital hybridization among O (CO2) and Mg atoms, O (CO2) atoms and K atoms, and the surface O atoms and K atoms. These interactions lead to the formation of (MgO)Mg-O(CO2) and (CO2)O−K−O(MgO) chemical bonds. The adsorption energy of CO2 on the K-promoted MgO surface increased from -0.32 eV to -1.01 eV compared to the pure surface, enhancing the adsorption of CO2.

Vacancy-Engineered 1D Nanorods with Spatially Segregated Dual Redox Sites for Visible-Light-Driven Cooperative CO2 Reduction.

Cooperative CO2 photoreduction with tailored organic synthesis offers a potent avenue for harnessing concurrently generated electrons and holes, facilitating the creation of both solar fuels and specialized chemical compounds. However, controlling the crystallization and morphologies of metal-free molecular nanostructures with exceptional photocatalytic activities toward CO2 reduction remains a significant challenge. These hurdles encompass insufficient CO2 activation potential, sluggish multielectron processes, delayed charge-separation kinetics, inadequate storage of long-lived photoexcitons, unfavorable thermodynamic conditions, and the precise control of product selectivity. Here, melem oligomer 2D nanosheets (MNSs) synthesized through pyrolysis are transformed into 1D nanorods (MNRs) at room temperature with the simultaneous engineering of vacancies and morphology. Transient absorption spectral analysis reveals that vacancies in MNRs trap charges, extending charge carrier lifetimes. Additionally, carbon vacancies enhance CO2 adsorption by increasing amine functional centers. The photocatalytic performance of MNRs for CO2 reduction coupled with benzyl alcohol oxidation is approximately ten times higher (CH3OH and aromatic aldehyde production rate 27 ± 0.5 and 93 ± 0.5 mmol g-1 h-1, respectively) than for the MNSs (CH3OH and aromatic aldehyde production rate 2.9 ± 0.5 and 9 ± 0.5 mmol g-1 h-1, respectively). The CO2 reduction pathway involved the carbon-coordinated formyl pathway through the formation of *COOH and *CHO intermediates, as mapped by in situ Fourier-transform infrared spectroscopy. The superior performance of MNRs is attributed to favorable energy-level alignment, enriched amine surfaces, and unique morphology, enhancing solar-to-chemical conversion.

Micro-Structure Engineering in Pd-InOx Catalysts and Mechanism Studies for CO2 Hydrogenation to Methanol.

Significant interest has emerged for the application of Pd-In2O3 catalysts as high-performance catalysts for CO2 hydrogenation to CH3OH. However, precise active site control in these catalysts and understanding their reaction mechanisms remain major challenges. In this investigation, a series of Pd-InOx catalysts were synthesized, revealing three distinct types of active sites: In-O, Pd-O(H)-In, and Pd2In3. Lower Pd loadings exhibited Pd-O(H)-In sites, while higher loadings resulted in Pd2In3 intermetallic compounds. These variations impacted catalytic performance, with Pd-O(H)-In catalysts showing heightened activity at lower temperatures due to the enhanced CO2 adsorption and H2 activation, and Pd2In3 catalysts performing better at elevated temperatures due to the further enhanced H2 activation. In situ DRIFTS studies revealed an alteration in key intermediates from *HCOO over In-O bonds to *COOH over Pd-O(H)-In and Pd2In3 sites, leading to a shift in the main reaction pathway transition and product distribution. Our findings underscore the importance of active site engineering for optimizing catalytic performance and offer valuable insights for the rational design of efficient CO2 conversion catalysts.

Promotion of CO2 Electroreduction on Bismuth Nanosheets with Cerium Oxide nanoparticles.

Formic acid (HCOOH) is a highly energy efficient product of the electrochemical CO2 reduction reaction (CO2RR). Bismuth-based catalysts have shown promise in the conversion of CO2 to formic acid, but there is still a great need for further improvement in selectivity and activity. Herein, we report the preparation of Bi nanosheets decorated by cerium oxide nanoparticles (CeOx) with high Ce3+/Ce4+ ratio and rich oxygen vacancies. The CeOx nanoparticles affect the electronic structures of bismuth, enhance CO2 adsorption, and thus promote the CO2RR properties of Bi nanosheets. Compared with elemental Bi nanosheets, the hetero-structured CeOx/Bi nanosheets exhibit much higher activity over a wide potential window, showing a current density of 16.1 mA cm-2 with a Faradaic efficiency of 91.1% at -0.9 V vs. reversible hydrogen electrode.

Synthesis and characterization of porous silica and composite films for enhanced CO₂ adsorption: A circular economy approach

This study explores the synthesis and application of carbon-negative technology that leverage circular economy and environmentally friendly methodologies. Porous silica using plant-derived silica sources and self-assembled lignin templates were prepared, achieving an impresive surface area of up to 104.76 m2/g. Additionally, we prepared porous composite films via a freeze-drying process incorporating polyvinyl alcohol (PVA). These films demonstrated enhanced tensile properties, with a tensile strength reaching 285.72 kPa. Notably, the film surfaces engaged in a third-body tribology mechanism, which endowed them with excellent abrasion resistance and a low friction coefficient. The specific surface area of the films was measured at 20.15 m2/g, making them ideal substrates for CO₂ adsorption functionalization. The functionalized films showcased outstanding CO₂ adsorption capabilities, with a maximum uptake of 29.38 mg/g. Furthermore, they retained over 90% of their adsorption capacity after five adsorption/desorption cycles. Under high CO₂ conditions, these composite films combine the desirable attributes of both solid and liquid adsorbents—high surface area, low volatility, and adsorption stability—contributing significantly to greenhouse gas mitigation and the pursuit of carbon neutrality.

Facilely incorporating aliphatic amines into a hydroxyl-containing robust metal-organic framework for enhancing CO2 adsorption

Two amine-incorporated composites, TETA@MIP-206-OH and TREN@MIP-206-OH, were facilely fabricated by incorporation of triethylenetetramine (TETA) and tris(2-aminoethyl)amine (TREN), respectively, into a hydroxyl-containing robust metal-organic framework, MIP-206-OH for enhancing CO2 adsorption. Characterizations revealed that the two amines were both successfully loaded into the pores by the interactions between the phenolic hydroxyl sites in the porous skeleton and the introduced amines groups without disrupting the inherent structure of MIP-206-OH. CO2 sorption experiments revealed that TETA@MIP-206-OH(1:1) possesses a CO2 adsorption capacity of 20.76 ± 2.3 cm3/g at 298 K and 1 atm, which is similar with that of MIP-206-OH itself (20.32 cm3/g) at the same condition. But, at relative lower pressure (P/P0 < 0.1), TETA@MIP-206-OH(1:1) exhibits much higher CO2 adsorption capacity that of MIP-206-OH itself, which finally is attributed to chemisorption feature verified by desorption hysteresis and Fourier transform infrared spectra measurements. TREN@MIP-206-OH(10:1) exhibits a higher CO2 adsorption capacity than both of them not only at lower pressure (P/P0 < 0.1) but also at about 1 atm with a value of 35.07 ± 0.59 cm3/g at 298 K. Moreover, the recycle sorption experiments revealed TETA@MIP-206-OH(1:1) composite can be reused for CO2 adsorption after being reactivated by heating, while the loaded aliphatic amines were still well immobilized in the framework even after running ten cycles of the CO2 sorption experiments. This work successfully demonstrated that incorporating aliphatic amines into hydroxyl-containing porous materials by simple acid-base interactions, effective recyclable adsorbents for CO2 capture can be facilely achieved.

PRELIMINARY STUDY ON PERFORMANCE OF Zn-DOPED ZEOLITE IN LOW-TEMPERATURE CO2 ADSORPTION

Zeolite has been identified as a potential low-temperature CO₂ adsorbent with the highest adsorption capacity among adsorbents in its category. However, its adsorption capacity remains relatively low, limiting its industrial application for CO₂ adsorption. Additionally, there is a need to increase the optimal adsorption temperature of this porous material to effectively adsorb CO₂ emitted from flue gas, which has an average temperature of 100 - 125°C. To address these challenges, a preliminary study on Zn-doped zeolite has been conducted. This study aims to investigate the ability of Zn-doped zeolite to enhance CO₂ adsorption capacity and its effect on the optimal temperature for CO₂ adsorption. Zinc-doped zeolite was synthesized by doping zinc oxide into natural zeolite using a zinc ion exchange method at different doping concentrations (0.2 M &amp; 1.0 M). Undoped natural zeolite was studied as a benchmark. Their CO₂ adsorption performance was tested using TGA at 30°C, 50°C, and 100°C. The effects of temperature and doping concentration on adsorption capacity were investigated. The adsorbent samples were characterized using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) analysis. It was found that increasing the temperature from 30°C to 50°C increased the CO₂ adsorption capacity, but the capacity decreased when the temperature was further increased to 100°C. Furthermore, increasing the doping concentration tended to enhance the CO₂ adsorption capacity. The highest adsorption capacity of 0.0281 g CO₂/g sorbent was observed in zinc-doped zeolite with a 1.0 M doping concentration at 50°C. The improvement was mainly attributed to the zinc oxide doped on the zeolite, which provided a functional group that formed chemical bonds with CO₂. This study also found that the adsorption rate of CO₂ was predominantly influenced by temperature, while the effect of doping concentration was less significant. All testing and characterization results suggested that the zinc-ion exchange method improved the CO₂ adsorption capacity of zeolite.

Impact of copper on activity, selectivity, and deactivation in the photocatalytic reduction of CO2 over TiO2

The photocatalytic reduction of CO2 to hydrocarbons may be a promising mechanistic route to reduce greenhouse gas CO2, convert it into useful products, and limit the direct emission of CO2. The photocatalytic reduction of CO2 is a reaction in which photons activate the photocatalyst by generating reduced and oxidized sites, that are re-oxidized and re-reduced by the reactants. The photocatalytic reduction of CO2 can produce various products, including CO, formic acid, formaldehyde, methanol, methane, etc.Here, the activity/selectivity of produced hydrocarbons in the presence of oxygen on various photocatalysts (TiO2, 5 wt%Cu-TiO2, 5 wt%Cu-C-TiO2) was determined.The reaction rate increased with increasing reaction time up to the first half an hour of the reaction but then started to decrease with photocatalysts, indicating photocatalyst deactivation, a rate-limiting step by hydroxyl radicals and adsorption of intermediates on TiO2. Carbon deposition as the origin of photocatalyst deactivation was confirmed using the TGA of the spent photocatalyst. Additionally, absorption of intermediates on spent catalysts were confirmed by FTIR. On the other hand, the conversion increased with time when copper was used as a promoter on a TiO2 compared with TiO2 due to its larger surface area and having more active sites.The photocatalysts were characterized using BET, ICP-OES, XRD, TGA, XPS, Fourier-Transform Infrared Spectroscopy (FTIR), and UV–Vis. The focus of this study was to determine the activity and efficacy of different photocatalysts (TiO2, 5 wt%Cu-TiO2, 5 wt%Cu-C-TiO2) by gas phase measurement, with a particular emphasis on obtaining reproducible data on conversion and selectivity as a function of irradiation time.The copper on TiO2 was found to be more selective towards sodium formate/formic acid with a maximum selectivity of ∼90 % in 4 h and had higher activity (74.3 µmol gcat-1 h-1). A maximum CO with a selectivity of 86 % was found when TiO2 was used in 4 h.Copper transfer electrons on the TiO2 surface enhance CO2 adsorption on the catalytic surface and is the reason for having higher valuable product on Cu-C-TiO2 and Cu-TiO2 compared with TiO2. Carbon in this experiment did not have a role and its effect was negligible.

Incorporation anthracene and Cu to NH2-Zr-UiO-67 metal-organic framework: Introducing the simultaneous selectivity and efficiency in photocatalytic CO2 reduction to ethanol

Metal-organic frameworks (MOFs) are considered promising candidates for photocatalytic CO2 reduction (PCR) into valuable organic fuels. However, compared to numerous reports regarding CO, CH4, and CHOOH generation, the explored MOFs have shown limited success in producing alcohols, particularly EtOH, through the PCR strategy. Existing MOFs also suffer from insufficient selectivity and efficiency. This study addresses these limitations by implementing a dual modification strategy on NH2-Zr-UiO-67 MOFs. This strategy involves synthesizing four MOF derivatives with different ratios of redox-active metal sites (Cu) to light absorption antenna (anthracene): 1:1, 2:1, 1:2, and 1:3. The as-synthesized MOFs (denoted as Cu/An (X:X)@NZU67 exhibited a remarkable capability for PCR-to-EtOH, without requiring a photosensitizer. The optimal amount of anthracene plays a crucial role in several aspects: improving light absorption, enhancing CO2 adsorption capacity, and promoting charge transfer/separation. Efficient charge transfer is critical for facilitating the multi-step electron transfer pathway required for ethanol synthesis. Notably, Cu/An (1:2)@NZU67 achieved an ethanol productivity of 624.17 µmolh−1g−1 for EtOH, which is, to the best of our knowledge, the highest efficiency reported for MOFs in PCR-to-EtOH conversion so far. Besides significant performance, the MOF showed 100% selectivity for EtOH production. This work represents a significant milestone in the field of PCR-to-EtOH transformation by providing a new perspective for designing MOF photocatalysts that can simultaneously improve both selectivity and efficiency.

Robust Nitrogen-Doped Microporous Carbon via Crown Ether-Functionalized Benzoxazine-Linked Porous Organic Polymers for Enhanced CO2 Adsorption and Supercapacitor Applications.

Nitrogen-doped carbon materials, characterized by abundant microporous and nitrogen functionalities, exhibit significant potential for carbon dioxide capture and supercapacitors. In this study, a class of porous organic polymer (POP) were successfully synthesized by linking Cr-TPA-4BZ-Br4 and tetraethynylpyrene (Py-T). The model benzoxazine monomers of Cr-TPA-4BZ and Cr-TPA-4BZ-Br4 were synthesized using the traditional three-step method [involving CH═N formation, reduction by NaBH4, and Mannich condensation]. Subsequently, the Sonogashira coupling reaction connected the Cr-TPA-4BZ-Br4 and Py-T monomers, forming Cr-TPA-4BZ-Py-POP. The successful synthesis of Cr-TPA-4BZ-Br4 and Cr-TPA-4BZ-Py-POP was confirmed through various analytical techniques. After verifying the successful synthesis of Cr-TPA-4BZ-Py-POP, carbonization and KOH activation procedures were conducted. These crucial steps led to the formation of poly(Cr-TPA-4BZ-Py-POP)-800, a carbon material with a structure akin to graphite. In practical applications, poly(Cr-TPA-4BZ-Py-POP)-800 exhibited a noteworthy CO2 adsorption capacity of 4.4 mmol/g, along with specific capacitance values of 397.2 and 159.2 F g-1 at 0.5 A g-1 (measured in a three-electrode cell) and 1 A g-1 (measured in a symmetric coin cell), respectively. These exceptional dual capabilities stem from the optimal ratio of heteroatom doping. The outstanding performance of poly(Cr-TPA-4BZ-Py-POP)-800 microporous carbon holds significant promise for addressing contemporary energy and environmental challenges, making substantial contributions to both sectors.

Valorization of argan paste cake waste: Enhanced CO2 adsorption on chemically activated carbon

This study addresses the critical need to reduce energy penalties in CO2 capture processes by exploring the potential of activated carbons derived from argan paste cake for post-combustion CO2 capture applications. Leveraging their cost-effectiveness, stability in humid conditions, and microporous structure, a series of activated carbons with diverse textural characteristics were synthesized through a two-step chemical activation process employing a KOH: biochar ratio of 1:1. Activation temperatures ranged from 700 to 850 °C. Characterization techniques such as Raman spectroscopy, X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, elemental analysis, and Fourier-transform infrared spectroscopy were employed to analyze the structural and chemical properties of the synthesized activated carbons. Remarkably, all synthesized samples exhibited excellent CO2 adsorption properties. Notably, the activated carbon sample prepared at 700 °C (APC-500–700) demonstrated the highest CO2 adsorption capacity, reaching up to 4.89 mmol/g at 0 °C and 2.98 mmol/g at 25 °C. Additional samples, including APC-500–800 and APC-500–850, exhibited CO2 adsorption capacities of 4.89 mmol/g and 4.83 mmol/g, respectively, at 0 °C, with corresponding values of 2.74 mmol/g and 2.60 mmol/g observed at 25 °C. Selectivity and stability tests were conducted to evaluate the adsorption performance under varied conditions, further highlighting the potential of activated carbon derived from argan paste cake in contributing to efficient CO2 capture processes. These findings underscore the significance of synthesis conditions in tailoring adsorption performance and pave the way for the sustainable utilization of waste biomass for environmental applications.

Ce3+-OV-Ce4+] Located Surface-Distributed Sheet Cu-Zn-Ce Catalysts for Methanol Production by CO2 Hydrogenation.

The metal-support interaction is crucial for the performance of Cu-based catalysts. However, the distinctive properties of the support metal element itself are often overlooked in catalyst design. In this paper, a sheet Cu-Zn-Ce with [Ce3+-OV-Ce4+] located on the surface was designed by the sol-gel method. Through EPR and X-ray photoelectron spectroscopy (XPS), the relationship between the content of oxygen vacancies and Ce was revealed. Ce itself induces the generation of [Ce3+-OV-Ce4+]. Through ICP-MS, XPS, and SEM-mapping, the Ce-induced formation of [Ce3+-OV-Ce4+] located on the catalyst surface was demonstrated. CO2-TPD and DFT calculations further revealed that [Ce3+-OV-Ce4+] enhanced CO2 adsorption, leading to a 10% increase in methanol selectivity compared to Cu-Zn-Ce synthesized via the coprecipitation method.