Suitable Pore Research Articles

Advancements in the Research of COF-Based Materials for Uranyl Enrichment

As a critical fuel for nuclear power operations, uranium plays an important role in ensuring the sustainable development of nuclear energy. In China, the demand for uranium resources is expected to reach 1.0-2.0 million tons per year by 2030. Currently, the principal methods employed for the enrichment of uranyl ions include photocatalysis, electrocatalysis, and adsorption. Covalent organic frameworks (COFs) have emerged as a popular choice for uranyl ion enrichment due to their suitable pore size, substantial specific surface area, and exceptional electrical conductivity. This review primarily focuses on the evaluation and characterization methods pertaining to uranyl enrichment, as well as the utilization of COFs-based materials for uranyl enrichment.

Coupling effect of vacancy defects and multi-adsorption sites in porous carbon cathode for high-performance aqueous zinc-ion hybrid capacitors

Aqueous zinc-ion hybrid capacitors (AZICs) are considered to be an auspicious electrochemical energy storage device due to their superior cycling stability and high power density, but the inadequate electrolyte ions storage active sites and inconsistent pore sizes of porous carbon materials result in poor energy storage performance. Thus, unveiling the interplay between the heteroatom dopant, carbon vacancy defects, and pore sizes in carbon cathode is essential for promoting the Zn2+ and SO42− ions storage capability. In this work, N, S co-doped multi-adsorption sites porous carbon materials with abundant vacancy defects (HC-0.2) are successfully prepared by a facile direct activating/annealing method, which exhibit strong interaction adsorption ability and boost ion and electron transfer. In terms of zinc storage performance, the HC-0.2 cathode exhibits a high capacity of 245.8mAh/g at 0.2A/g and a long cycling stability with 82.3 % capacity retention over 10,000 cycles at 10A/g. Moreover, the HC-0.2//Zn device has a supreme energy density of 164.1Wh/kg and an ultrahigh power density of 30.1 kW/kg. Meanwhile, through theoretical calculations, the N, S multi-adsorption sites, a suitable pore size, and vacancy defects of the HC-0.2 cathode are crucial for improving the Zn2+ and SO42− ions storage capability. This work can provide a comprehensive understanding of the coupling effect of the multi-adsorption sites and vacancy defects of N, S co-doped porous carbon materials on energy storage capability.

The surface and interlayer modification of montmorillonite and its potential application for thermal energy storage

Phase change materials (PCMs) could take full advantage of clean and renewable energy, because of their ability to convert and store various energy. However, due to the leakage and low heat storage capacity, the large-scale commercial application of PCMs is seriously limited. In this work, natural montmorillonite (MMT) was modified by organic amine coupling agent that was assembled into the interlayer of MMT. The energy storage performance and the stability of composite PCMs were significantly improved by using a novel frame of MMT encapsulated Paraffin (PA). The MMT-KH550-HAc/PA composite PCMs prepared by organic intercalation provides suitable pore structure and hydrophilicity to encapsulate more PA, resulting in the highest latent heat capacity (150 J/g) that is significantly increased by 144.1% from 60 J/g. Meanwhile, the energy storage stability of MMT-KH550-HAc/PA is also improved, and the latent heat of phase change is reduced by 3.2% after 100 cycles. The present MMT-KH550-HAc/PA has remarkable latent heat capacity and energy storage stability, which can be potentially applied to the solar water heaters.

Efficient CO2 capture and separation in TpPa COFs: Synergies from functional groups and metal Li

Covalent organic frameworks (COFs) have emerged as promising materials for CO2 capture and separation owing to their exceptional structural stability. Herein, grand canonical Monte Carlo simulation (GCMC) and density functional theory (DFT) were used to first screen the most favorable functional group in the COFs consisting of 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa) functionalized with –OH, –COOH, and –SO3H, respectively (TpPa-X). Subsequently, the H atoms of –SO3H, the best functional group, were replaced by Li atoms to form –SO3Li, revealing the synergies of functional group –SO3H and Li modification on selective CO2 capture. TpPa-OLi/COOLi were also constructed to confirmed the universality of this synergistic effect. The introduction of functional groups enhanced the CO2 capture and separation performances by creating a more suitable pore environment. The Li introduction increased the structural polarity and provided strong adsorption sites, further improving the selective CO2 capture performance. Notably, TpPa-SO3Li exhibited a remarkable CO2 adsorption capacity of 136.11 cm3 cm−3 with the CO2 over N2/CH4 selectivity of 264.22/164.38, respectively, at 298 K and 1.0 bar. Structural stabilities, pore characteristics, gas adsorption distribution, isothermal adsorption heat, and interactions were adopted to reveal the synergistic effect between functional groups and Li in enhancing CO2 capture and separation.

Template-assisted fabrication of polyether ether ketone hollow fiber membrane for highly efficient separation of binary dye mixtures

Poly(ether ether ketone) (PEEK) is among the most reliable membrane materials in membrane-based separation processes due to its excellent properties especially under harsh environment. Successfully implementing the controllable construction of the pore structure into the fabrication process of PEEK hollow fiber membranes (HFMs) can make a significant contribution to addressing the issue of membrane selectivity and permeability. Herein, we developed a flexible route for manufacturing PEEK HFMs by melt-spinning technology combined with the template-assisted crystallization process. This route effectively reduced the amount of organic solvent in the membrane preparation process, and the crystallization induced strategy remarkably improved the connectivity of membrane pore structure and fixed pore structure of PEEK HFMs. Furthermore, we conducted a comprehensive investigation into the separation mechanism and performance stability of the prepared membranes in binary dye mixtures. The results unveiled that the suitable pore structure of the PEEK HFMs that maintained a high salt permeability with a high dye retention, synergized with strong negative charge contributed to excellent performance in dye/salts or dye/dye binary mixtures separations. A long-term stability of PEEK HFMs for treatment of the simulated textile wastewater with rejection coefficient of above 99% to dyes like congo red (CR) and a low NaCl rejection (<10%) indicated that PEEK HFMs have a bright prospect in dye/salt separation for water purification and resource reclamation.

Vascular tissue-derived hard carbon with ultra-high rate capability for sodium-ion storage

Vascular tissue helps quickly pass the nutrients and water through the plant. Inspiringly, the transport of electrolyte solutions within such biological tissue may also play an essential role in governing the high-current performance of sodium-ion storage. Herein, we report a facile and efficient approach to fabricate a vascular tissue-derived hard carbon (VHC) by an integrated procedure of leave stripping, carbonization and alkali/acid washing. By meticulously adjusting the pyrolysis temperatures, hierarchical microchannel carbon with abundant turbostratic nanodomains, suitable pore size and special surface functional groups can be obtained, enabling high specific capacity and excellent rate performances. It is believed that the vascular tissue-derived carbon can significantly shorten sodium ion transport paths and further enhance the storage performance on the surface and within the electrode materials, making it a promising candidate for sodium-ion batteries.

Fluorinated MOF‐Based Hexafluoropropylene Nanotrap for Highly Efficient Purification of Octafluoropropane Electronic Specialty Gas

AbstractHigh‐purity octafluoropropane (C3F8) electronic specialty gas is a key chemical raw material in semiconductor and integrated circuit manufacturing industry, while selective removal of hexafluoropropylene (C3F6) impurity for C3F8 purification is essential but a challenging task. Here we report a fluorinated cage‐like MOF Zn‐bzc‐CF3 (bzc=5‐(trifluoromethyl)‐1H‐pyrazole‐4‐carboxylic acid) for C3F6/C3F8 separation. The incorporation of −CF3 groups not only provides suitable pore aperture size for highly efficient size‐exclusive C3F6/C3F8 separation, but also creates hydrophobic microenvironments, endowing Zn‐bz‐CF3 high chemical stability. Remarkably, Zn‐bzc‐CF3 exhibits high C3F6 adsorption capacity while excluding C3F8, achieving ideal molecular‐sieving C3F6/C3F8 separation. Breakthrough experiments show that Zn‐bzc‐CF3 can efficiently separate C3F6/C3F8 mixture and high‐purity C3F8 (99.9 %) can be obtained.

Ultrarapid Gelation of Porous Ti3C2Tx MXene Monoliths Induced by Ionic Liquids.

Gelation is a promising method to assemble 3D macroscopic structures from MXene sheets for various applications. However, the fine control and scalable manufacturing of 3D MXene monoliths remains a great challenge. Herein, the controllable gelation of Ti3C2Tx MXene initiated by various ionic liquids (ILs) is first proposed, where the IL serve as linkers to bond the nanosheets together through electrostatic and hydrogen bonding interactions, forming 3D monoliths with well-adjustable structure. Furthermore, density functional theory calculations and experiments further reveal the cross-linking effect of different ILs. Typically, 3D porous structure with high specific surface area, suitable pore size, and improved electrolyte affinity is designed through the cross-linking of Ti3C2Tx with 1-vinyl-3-ethylimidazole bromide ([C2VIm]Br-Ti3C2Tx). Due to the strong coupling, the as-synthesized monolith possesses excellent rate performance and high energy density. The methodology is quite flexible, controllable, and universal that provides a new perspective for promoting innovative applications of 2D materials.

Fluorinated MOF-Based Hexafluoropropylene Nanotrap for Highly Efficient Purification of Octafluoropropane Electronic Specialty Gas.

High-purity octafluoropropane (C3F8) electronic specialty gas is a key chemical raw material in semiconductor and integrated circuit manufacturing industry, while selective removal of hexafluoropropylene (C3F6) impurity for C3F8 purification is essential but a challenging task. Here we report a fluorinated cage-like MOF Zn-bzc-CF3 (bzc=5-(trifluoromethyl)-1H-pyrazole-4-carboxylic acid) for C3F6/C3F8 separation. The incorporation of -CF3 groups not only provides suitable pore aperture size for highly efficient size-exclusive C3F6/C3F8 separation, but also creates hydrophobic microenvironments, endowing Zn-bz-CF3 high chemical stability. Remarkably, Zn-bzc-CF3 exhibits high C3F6 adsorption capacity while excluding C3F8, achieving ideal molecular-sieving C3F6/C3F8 separation. Breakthrough experiments show that Zn-bzc-CF3 can efficiently separate C3F6/C3F8 mixture and high-purity C3F8 (99.9 %) can be obtained.

Novel recovery of a low-concentration gold thiosulfate complex through electroreduction via a walnut shell charcoal electrode

Low-concentration Au(S2O3)23− recovery is an urgent issue to facilitate the application of thiosulfate leaching instead of cyanide leaching in factories. Herein, this work presents a novel recovery of low-concentration Au(S2O3)23− combining adsorption and electrodeposition (electroreduction) to realize high Au(S2O3)23− recovery in the form of gold particles (Au0). Walnut shells were used as the raw material for the successful preparation of charcoal with porous structure and rich oxygen-containing functional groups. Walnut shell charcoal (WSC) as the electrode achieved efficient recovery of low-concentration Au(S2O3)23−. The recovery under low-concentration conditions was higher than 90%, with the highest reduction of 46.97 mg·g−1. Applying a suitable low voltage (0.8 V) facilitated low-concentration Au(S2O3)23− recovery, which was immensely improved than that without voltage. Au(S2O3)23− recovery performances under applied voltage via the WSC electrode were related to electrochemical abilities, including reaction intensity and charge transfer. More reactive sites containing suitable pores and oxygen functional groups were beneficial for the reduction reaction. This work offers a new way to recover low-concentration Au(S2O3)23− via cheap charcoal electrodes from solutions for application in the cyanide-free leaching method in industry.

Synthesis and characterization of Co3O4 nanoneedle structures for enhancing the supercapacitive performance

The present study focuses on the synthesis of Co3O4 nanoneedles utilizing a deep eutectic solvent (DES) comprising choline chloride and urea, renowned for its environmentally advantageous characteristics. The deposition time was modified to achieve the desired Co3O4 nanoneedle structure, as indicated by several analyses including structural, vibrational, morphological, elemental, surface area, and pore distribution examinations. Following the initial characterization, other electrochemical storage characterizations were conducted. Experimentally it has been found that the optimum Co3O4 samples yielded 1-D mesoporous nanoneedle structure with the features like (i) a substantial presence of oxygen vacancies, (ii) a relatively greater surface area, and (iii) a suitable pore size. As a result, of which it shows significant specific capacitance of 880 Fg−1 when subjected to a current density of 0.66 Ag−1 in a 2 M KOH aqueous electrolyte. Additionally, it displayed excellent retention of 118% at 60 mVs−1 scan rate after undergoing 5000 cycles. Moreover, a symmetric supercapacitor with a liquid electrolyte was constructed using identical nanoneedle Co3O4 materials as both the cathode and anode. The experimental results demonstrated a specific capacitance of 98.39 Fg−1 at a current density of 0.66 Ag−1. Furthermore, the device exhibited an energy density of 18 Whkg−1 along with a power density of 200 Wkg−1, demonstrating exceptional cycling stability of 94% over a span of 5,000 cycles.

Amino-functionalized iron-based MOFs for Rhodamine B degradation in heterogeneous photo-Fenton system

Amino-functionalized iron-based MOFs were successfully synthesized and used for the photo-Fenton-catalyzed degradation of Rhodamine B (RhB). The degradation efficiency of NH2-MIL-53(Fe) towards RhB (95.0%) exceeded that of NH2-MIL-88B(Fe) (87.0%) and NH2-MIL-101(Fe) (88.0%), which might be mainly because that NH2-MIL-53(Fe) had the most suitable specific surface area and pore volume, and the best light absorption properties. Additionally, NH2-MIL-53(Fe) exhibited higher degradation efficiency than MIL-53(Fe) (84.0%), possibly owing to the incorporation of amino functional groups that inhibited the recombination of photogenerated electron-hole pairs and enhanced visible light responsiveness. Remarkably, NH2-MIL-53(Fe) had a good degradation effect on RhB in a wide range of pH (3.0–7.0), and the degradation rate was still as high as 90.0% after 5 consecutive degradation experiments. The degradation process was predominantly influenced by the involvement of ·OH and 1O2, as evidenced by the outcomes of free radical capture experiments. Possible degradation pathways of RhB were proposed by mass spectrometry.

Research on CeO2 Activated Carbon Electrode Capacitance Method for Sulfate Removal from Mine Water

Sulfate is a typical characteristic pollutant in mine water. Because of its high concentration and large discharge of mine water, it has become a difficult problem in mineral exploitation. Capacitive deionization (CDI) is an innovative and economical removal technology. There are few reports on the use of CDI to remove SO42− from mine water. In this study, a CeO2 activated carbon electrode with good wettability, excellent electrochemical performance, and suitable pore structure was prepared by the sol-gel method. The application of the CeO2 activated carbon electrode to the capacitive method for treating high SO42− mine water was investigated using simulated wastewater and actual mine water. The study structure shows that CeO2:activated carbon (AC) has the best wettability, the highest specific capacitance, and the lowest electrical conductivity when the mass ratio of CeO2 is 5%. At 100 mg/L, the electrode has the maximum SO42− ion specific adsorption capacity (SAC). At 1 V and 20 mL/min, this value is measured. The electrode has a SAC value of 9.36 mg/g, far higher than the AC electrode’s 4.1 mg/g. The effect of CDI process factors such the voltage, flow rate, and initial concentration was studied to find the best treatment method. SAC retention is 91% after 10 adsorption–desorption cycles, demonstrating outstanding electrode performance. Under the best CDI process (1.4 volts, 30 mL/min), mine water was treated. After 20 cycles of treatment, the concentration of SO42− in mine water decreased from 1170 mg/L to 276.46 mg/L, and the removal rate was 76.37%. This study proved that the CeO2 modified activated carbon electrode capacitance method can effectively remove sulfate ions and other ions from mine water.

Fabrication of Soft-Hard Heterostructure Porous Carbon with Enhanced Performance for High Mass-Loading Aqueous Supercapacitors.

With the increasing attention to energy and environmental issues, the high value-added utilization of biomass and pitch to functional carbon materials has become an important topic in science and technology. In this work, the soft-hard heterostructure porous carbon (NRP-HPC) is prepared by bio-template method, in which biomass and pitch are used as hard carbon and soft carbon precursors, respectively. The prepared NRP-HPC-4 shows high specific surface area (2293m2g-1), suitable pore size distribution, good conductivity (0.25Ωcm-1), and strong wettability. The synergistic effect of soft carbon and hard carbon ensures the composite material exhibiting excellent electrochemical performance for high mass loading (12.0mgcm-2) aqueous supercapacitor, i.e., high specific capacitance (304.69Fg-1 at 0.1Ag-1), high area capacitance (3.67Fcm-2 at 0.1Ag-1), high volumetric specific capacitance (202.74Fcm-3 at 0.1Ag-1), low open-circuit voltage attenuation rate (21.04mVh-1), good voltage retention (79.12%), and excellent cyclic stability (92.04% capacitance retention and 100% coulombic efficiency after 20000 cycles). The composite technology of soft carbon and hard carbon not only ensures the prepared porous carbon electrode materials with enhanced electrochemical performance, but also realizes the high value-added coupling utilization of biomass and pitch.

Heteroatom-doped porous carbon materials for high performance supercapacitors

Heteroatom-doped carbon materials have considerable potential for applications in energy storage devices (ESDs). In this study, an interconnected B/N/O/P co-doped porous carbon materials (B5-CPPCN-700) was synthesised using a simple one-step method with zinc nitrate hexahydrate and 4′-(4-phosphonylphenyl)−3,2′:6′,3″-terpyridine as raw materials through KOH activation. The as-prepared B5-CPPCN-700 had a large specific surface area, rough surface for ion adsorption, and suitable pore size distribution for electron transport. Moreover, the co-doped B/N/O/P species—particularly the B species—in B5-CPPCN-700 provided active sites and additional pseudocapacitance. These structural and morphological features ensured a high specific capacitance of 503.3 F/g at 0.5 A/g. Furthermore, the assembled symmetric supercapacitor delivered a satisfactory specific energy, specific power (14.98 Wh/kg at 300 W/kg and 6.97 Wh/kg at 22,800 W/kg), and specific capacitance (149.8 F/g at 0.5 A/g and 77.2 F/g at 40 A/g). This study paves the way for the preparation of high-capacitance porous carbon materials for ESDs.

Rationally designed nanotrap structures for efficient separation of rare earth elements over a single step

Extracting rare earth elements (REEs) from wastewater is essential for the growth and an eco-friendly sustainable economy. However, it is a daunting challenge to separate individual rare earth elements by their subtle differences. To overcome this difficulty, we report a unique REE nanotrap that features dense uncoordinated carboxyl groups and triazole N atoms in a two-fold interpenetrated metal-organic framework (named NCU-1). Notably, the synergistic effect of suitable pore sizes and REE nanotraps in NCU-1 is highly responsive to the size variation of rare-earth ions and shows high selectivity toward light REE. As a proof of concept, Pr/Lu and Nd/Er are used as binary models, which give a high separation factor of SFPr/Lu = 796 and SFNd/Er = 273, demonstrating highly efficient separation over a single step. This ability achieves efficient and selective extraction and separation of REEs from mine tailings, establishing this platform as an important advance for sustainable obtaining high-purity REEs.

Application of Covalent Organic Framework-Based Solid-Phase Microextraction for Efficient and Direct Analysis of Neurotransmitters in the Striatum of Nicotine-Addicted mice

This study developed and validated a novel solid-phase microextraction (SPME) method based on covalent organic framework (COF) for the simultaneous analysis of 10 neurotransmitters (NTs) in mice brain tissue using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The synthesized COF was utilized as SPME fiber coating, exhibited a suitable pore size and macromolecule exclusion capability, ensuring excellent thermal stability and high adsorption efficiency for NTs. This allowed direct extraction from brain homogenates, eliminating the need for protein precipitation. And the COF-based SPME fiber exhibited good reusability throughout eight successive recycling cycles. The SPME-UHPLC method demonstrated excellent linearity (correlation coefficients > 0.99), low intra- and inter-day precision (RSDs ≤ 9.5 % and ≤ 10.6 %, respectively), and acceptable matrix effects (ranging 84.3 % to 117.3 %). The developed method was then applied to analyze NTs in the striatum of nicotine-addicted mice, and the statistical analysis revealed significant shifts in the concentrations of dopaminergic, serotonergic, glutamatergic, addiction and deepened the understanding of addiction's neurobiology. This method offers a sensitive and efficient approach for extracting polar NT analytes in complex matrices, profiling NT alterations linked to addiction, and holds potential for early detection and treatment of addiction disorders. It could contribute significantly to addiction neurobiology and neurological disease research.

Water transferable, customizable highly ordered honeycomb film from polystyrene foam waste for complex surface patterning in confined space

AbstractThe disposal of plastic foam, mostly composed of polystyrene, poses significant environmental challenges due to its high popularity, slow degradation, and low cost. To address this problem, recycling polystyrene foam waste (PF) has emerged as a promising solution to reduce plastic pollution. This paper presents a novel approach to mass‐produce highly ordered, porous honeycomb‐patterned film (hc‐film) using wasted PF as the raw material. The hc‐film is produced using an improved phase separation (IPS) method that utilizes methanol as a suitable pore inducer and template droplet stabilizer. Methanol provides the hc‐film with customizable features such as pore ordering, size, and separation. The freestanding hc‐film, achieved by adopting a water‐soluble polystyrene sulfonate as a scarified layer, can be transferred and utilized as a flexible mold to pattern various solid substrates with complicated surface morphologies using the pre‐impregnated technique. This study demonstrates the potential of this cost‐effective and efficient approach for various applications, such as super/anti‐wetting surfaces, microelectronics, optical devices, sensors, and nanogenerators.

One Scalable and Stable Metal-Organic Framework for Efficient Separation of CH4/N2 Mixture.

Separating CH4 from coal bed methane is of great importance but challenging. Adsorption-based separation often suffers from low selectivity, poor stability, and difficulty to scale up. Herein, a stable and scalable metal-organic framework [MOF, CoNi(pyz-NH2)] with multiple CH4 binding sites was reported to efficiently separate the CH4/N2 mixture. Due to its suitable pore size and multiple CH4 binding sites, it exhibits excellent CH4/N2 selectivity (16.5) and CH4 uptake (35.9 cm3/g) at 273 K and 1 bar, which is comparable to that of the state-of-the-art MOFs. Theoretical calculations reveal that the high density of open metal sites and polar functional groups in the pores provide strong affinity to CH4 than to N2. Moreover, CoNi(pyz-NH2) displays excellent structural stability and can be scale-up synthesized (22.7 g). This work not only provides an excellent adsorbent but also provides important inspiration for the future design and preparation of porous adsorbents for separations.

Pore parameter selection for fused deposition modeling of gas diffusion layers in proton exchange membrane fuel cells

AbstractBecause of the global energy crisis, many researchers have focused their efforts on fuel cells. The gas diffusion layer (GDL) is a fundamental component of proton exchange membrane (PEM) fuel cells. The manufacturing procedures for traditional carbon‐based GDLs are sophisticated and energy‐intensive, and have design flexibility constraints, making it difficult to build complicated forms and structures. Additive manufacturing is widely used in a variety of fields, with the fused deposition modeling (FDM) technique being the most popular method. Prior to conducting systematic research on the printed GDLs, it is necessary to investigate the pore parameters with the support of FDM technique. In this research, the initial step involves material selection, FDM printer selection, and modeling. Subsequently, printing analysis and sample characterization are conducted to select an acceptable pore shape. A water drainage test determines the appropriate pore size, followed by additional tests for acceptable porosity range. The square pore shape is determined to be more suitable. A pore side length of 1.0 mm is identified. Furthermore, a suitable pore range of 10.9%–30.3% is identified. Next step, the printed GDLs will undergo further testing to investigate their suitability to be used in PEM fuel cells.