Ultrahigh Specific Surface Area Research Articles

Fiber-shaped all-solid-state symmetric supercapacitors based on poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)/carbonized zeolitic imidazolate framework-8

Fiber-shaped supercapacitors (FSCs) have lately attracted interest due to their tiny size, great flexibility, and the prospect of application in wearable devices. Among the FSCs, those based on poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) (PFs) are particularly promising due to their outstanding electrochemical and mechanical properties. However, the areal capacitance and cycling stability of these materials are still far below the practical requirement. In this study, zeolitic imidazolate framework-8 (ZIF-8) is utilized to prepare nitrogen-doped porous carbon (c-ZIF-8), which is then integrated into PFs by a hybrid spinning method. Because of its ultra-high specific surface area (1633.1 m2 g−1) and abundant pores, c-ZIF-8 provides more electrochemically active sites and remarkably increases the capacitance of the composite fibers. They exhibit a high specific capacitance of 635 mF cm−2 and excellent cycling stability in 10,000 cycles.

Improved proton conductivity and mechanical performance of phosphoric acid doped aminated PAF-1 reinforced OPBI for high temperature proton exchange membranes

High-temperature proton exchange membranes (HT-PEMs) doped with phosphoric acid (PA) can achieve high proton conduction at high phosphoric acid doping level (ADL). However, polybenzimidazole (PBI) membranes have problems with PA loss, poor mechanical properties, and other issues at high ADL. Herein, PAF-1-NH2 was obtained through an amination of porous aromatic frameworks with an ultrahigh specific surface area (PAF-1), and APAF-1 was prepared by vacuum injection of PA on PAF-1-NH2 to increase the ADL through the high basic site amount and specific area. APAF-1/OPBI composite HT-PEMs was prepared by solution casting method. The composite membrane maintained superior mechanical properties, high proton conductivity and low dimensional swelling ratio (166.2%) even with a high PA doping rate (328.5%), due to the rigid structure of APAF-1 and the strong interfacial interaction between APAF-1 and OPBI. The mechanical strength and proton conductivity of the 10%APAF-1/OPBI were 20.86 MPa and 0.107 S cm−1 at 200 °C, respectively, which was about 2.43 times that of the OPBI membrane (0.044 S cm−1). When the catalyst Pt dosage was only 0.3 mg cm−2, the peak power density of the H2/O2 fuel cell at 180 °C was 366.6 mW cm−2. Therefore, this work presented a new approach for preparing HT-PEMs with excellent comprehensive properties.

Micropores enriched ultra-high specific surface area activated carbon derived from waste peanut shells boosting performance of hydrogen storage

This research effectively synthesized peanut shell-derived carbon materials (PWAC-X) with outstanding high specific surface area (SSA) and significant number of microporous structures. As a consequence of optimizing ratio of precursors and KOH, an ultra-high SSA of 3728.06 m2 g−1 and total volume of 2.21 cm3 g−1 for PWAC-4 was achieved, resulting in a remarkable hydrogen storage capacity of 6.36 wt% at 77 K and 40 bar. DFT simulations were further utilized to demonstrate interactions between N/O-containing functional groups (N-5, N-6, –OH, C–O–C) and hydrogen molecules. The hydrogen adsorption process on activated carbon was shown to be an exothermic reaction, and carbon containing N/O functional groups were more suitable for hydrogen adsorption than pure carbon materials. In brief, this study has provided an easy-to-scale-up method for obtaining ultra-high SSA carbon materials to storage hydrogen and addresses an intractable utilization of waste products.

Construction of the hierarchical porous biochar with an ultrahigh specific surface area for application in high-performance lithium-ion capacitor cathode

Biochar with a highly accessible specific surface area can display a higher performance when it is used as the cathode of lithium-ion capacitors. Facing the complex composition and diversity of biomass precursors, there is a lack of a universally applicable method to construct hierarchical porous biochar controllably. In this work, a multi-stage activation strategy combining the feature of different activation methods is proposed for this target. To confirm the porous characteristic in prepared samples, N2 adsorption–desorption and transmission electron microscope were used. As the optimal sample, BC-P3K4S had the highest specific surface area of 3583.3 m2 g−1. Evaluated as the electrode for a lithium-ion capacitor, BC-P3K4S displayed a capacity of 139.1 mAh g−1 at 0.1 A g−1. After coupling it with pre-lithiated hard carbon, the full device exhibited a high energy density of 129.3 W h kg−1 at 153 W kg−1. The work outlined herein offers some insights into the preparation of hierarchical porous biochar from complex biomass by multistep activation method.Graphical

Single-atom Anchored Curved Carbon Surface for Efficient CO2 Electro-reduction with Nearly 100% Co Selectivity And Industrially-relevant Current Density.

Although single metal atoms on porous carbons (PCs) have been widely used in electrochemical CO2 reduction reaction, these systems have long relied on flat graphene-based models, which are far beyond reality because of abundant curved structures in PCs, the effect of curved surface has long been ignored. In addition, the selectivity generally decreases under high current density, which severely limits practical application. Herein, the theoretical calculations reveal that the single-Ni-atom on curved surface can simultaneously enhance the total density of states around Fermi level and decrease the energy barrier for *COOH formation, thereby enhancing catalytic activity. We report a rational molten salt approach for preparing PCs with ultra-high specific surface area of up to 2635 m2 g-1 . As determined by cutting-edge techniques, single-Ni-atom on curved carbon surface is obtained and used as catalysts for electrochemical CO2 reduction. The CO selectivity reaches up to 99.8% under industrial-level current density of 400mA cm-2 , outperforming state-of-the-art PC-based catalysts. Not only this work offers a new method for the rational synthesis of single atom catalysts with strained geometry to host rich active sites, but also provides in-depth insights for the origin of catalytic activity of curved structure-enriched PC-based catalysts. This article is protected by copyright. All rights reserved.

The synthesis and functionalization of metal organic frameworks and their applications for the selective separation of proteins/peptides.

Recently, proteins separation has drawn great interest for the full investigation of a proteome because the proteins separation is the precondition when conducting clinical research or proteomics research. Metal organic frameworks (MOFs) are fabricated via covalent connection between organic ligands and metal ions/clusters units. MOFs have attracted much attention due to the ultra-high specific surface area, tunable structure, more metal site or unsaturated site, and chemical stability. Over the past decade, different functionalization types of MOFs have been reported in combination with amino acids, nucleic acids, proteins, polymers, and nanoparticles for various applications. In this review, the synthesis and functionalization of MOFs have been thoroughly discussed, and we introduced the existing problems and development trends in these fields. Furthermore, MOFs as advanced adsorbents for selective separation of proteins/peptides are summarized. Additionally, we present a comprehensive prospects and challenges in the preparation of robust functional MOFs-based adsorbents and make a final outlook on their future development prospects in selective separation of proteins/peptides.

Biochar with enhanced performance prepared from bio-regulated lignocellulose for efficient removal of organic pollutants from wastewater

This work presented a novelty method for preparing lignocellulosic materials with reinforced performances, that is, the lignocellulose of corn straw was bio-regulated into cellulose, hemicellulose, and lignin via three types of microorganisms (Aspergillus niger, Myrothecium verrucaria, Trichoderma reesei) with cross treatment. Three different types of biochar were then prepared by the carbonization and combined alkali activation processes. The results showed that the great quantity of micro/mesopores endowed biochars ultra-high specific surface areas up to 2881, 2986, and 2878 m2 g−1. Biochars exhibited ultra-high maximum adsorption capacities for crystal violet (CV) and tetracycline hydrochloride (TC), which was higher than that of most adsorbents including the corn straw-based carbon and multi-walled carbon nanotube. After five cycles, the samples maintained a removal rate of over 70% for CV and over 60% for TC, proving their good potential for recycling. This study showed that the bio-regulation of lignocellulose was not only an effective method to develop materials with enhanced adsorption performances, but also provided a feasible idea for the comprehensive utilization of lignocellulose.

Rational construction of hierarchical porous carbon with ultrahigh specific surface area and rich heteroatoms toward high-performance supercapacitors

Favourable pore configuration and active heteroatoms contribute significantly to intrinsic electrochemical performance of carbon materials. Herein, N, S co-doped porous carbons are prepared through a two-step calcination process, in which pre-carbonized chitosan, thiourea and potassium hydroxide are served as carbon source, dopant and activator, respectively. Optimal sample CTK-3 exhibits considerable specific surface area (SSA), remarkable micropore configuration and heteroatom content. Therefore, it exhibits a remarkable specific capacitance (309.4 F g−1 at 0.5 A g−1), cyclic stability (98.7% after 8000 cycles) and rate capability. Moreover, the symmetrical supercapacitors assembled by CTK-3 yields an ultrahigh energy density of 15.6 Wh kg−1, indicating appealing application potential of the N, S co-doped porous carbon.

A robust and ultra-high-surface hydrogen-bonded organic framework promoting high-efficiency solid phase microextraction of multiple persistent organic pollutants from beverage and tea.

Persistent organic pollutants (POPs) are widely distributed in the environment and are toxic, even at low concentrations. In this study, we first used hydrogen-bonded organic framework (HOF) to enrich POPs, based on solid phase microextraction (SPME). The HOF called PFC-1 (self-assembled by 1,3,6,8-tetra(4-carboxylphenyl)pyrene) has an ultra-high specific surface area, excellent thermochemical stability, and abundant functional groups, making it potential to be an excellent coating in SPME. And the as-prepared PFC-1 fiber have demonstrated outstanding enrichment abilities for nitroaromatic compounds (NACs) and POPs. Furthermore, the PFC-1 fiber was coupled with gas chromatography-mass spectrometry (GC-MS) to develop an ultrasensitive and practical analytical method with wide linearity (0.2-200ng·L-1), low detection limits for organochlorine pesticides (OCPs) (0.070-0.082ng·L-1) and polychlorinated biphenyls (PCBs) (0.030-0.084ng·L-1), good repeatability (6.7-9.9%), and satisfactory reproducibility (4.1-8.2%). Trace concentrations of OCPs and PCBs in drinking water, tea beverage, and tea were also determined precisely with the proposed analytical method.

Attachment of Fe3O4 nanoparticles on UiO-66: A stable composite for efficient sorption and reduction of selenite from water

In the present work, Fe3O4 nanoparticles were attached to the surface of UiO-66, a zirconium-based metal–organic framework material and the composite material formed was used to remove selenite (Se(IV)) in water. The Fe3O4/UiO-66 composite were assembled by a facile two-stage strategy. Benefiting from the ultra-high specific surface area of UiO-66, the Fe3O4/UiO-66 also had a large specific surface area, which made it easier to expose the active sites of Fe3O4 on the surface of UiO-66. The XPS and Mössbauer spectroscopy analysis indicated that there was charge transfer between Fe3O4 and UiO-66 in the Fe3O4/UiO-66, which made the Fe3O4 on the surface of UiO-66 had enhanced reductive activity. The mechanism of Fe3O4/UiO-66 to removed Se(IV) from the solution was further investigated by Zeta potential, FT-IR, SEM, TEM, and XPS spectra. The results indicated that the Fe3O4 nanoparticles on the surface of UiO-66 not only interacted with selenite through electrostatic action and inner-sphere complex but could also reduce a large amount of selenite to the insoluble Se0. The combination of these three actions finally strengthened the removal of selenite. This study cloud promote the practical application of MOF-based composites in removing heavy metal ions.

Bioinspired Hierarchical Carbon Structures as Potential Scaffolds for Wound Healing and Tissue Regeneration Applications.

Engineered bio-scaffolds for wound healing provide an attractive treatment option for tissue engineering and traumatic skin injuries since they can reduce dependence on donors and promote faster repair through strategic surface engineering. Current scaffolds present limitations in handling, preparation, shelf life, and sterilization options. In this study, bio-inspired hierarchical all-carbon structures comprising carbon nanotube (CNT) carpets covalently bonded to flexible carbon fabric have been investigated as a platform for cell growth and future tissue regeneration applications. CNTs are known to provide guidance for cell growth, but loose CNTs are susceptible to intracellular uptake and are suspected to cause in vitro and in vivo cytotoxicity. This risk is suppressed in these materials due to the covalent attachment of CNTs on a larger fabric, and the synergistic benefits of nanoscale and micro-macro scale architectures, as seen in natural biological materials, can be obtained. The structural durability, biocompatibility, tunable surface architecture, and ultra-high specific surface area of these materials make them attractive candidates for wound healing. In this study, investigations of cytotoxicity, skin cell proliferation, and cell migration were performed, and results indicate promise in both biocompatibility and directed cell growth. Moreover, these scaffolds provided cytoprotection against environmental stressors such as Ultraviolet B (UVB) rays. It was seen that cell growth could also be tailored through the control of CNT carpet height and surface wettability. These results support future promise in the design of hierarchical carbon scaffolds for strategic wound healing and tissue regeneration applications.

Three-dimensional porous nitrogen-doped carbon nanosheets with ultra-high surface area for high-performance oxygen reduction reaction electrocatalysts

A series of three-dimensional (3D) porous nitrogen-doped carbon nanosheets (PNCNs) have been successfully fabricated via a high-pressure carbonization followed by high-temperature thermal treatment. With the prolonging of thermal treatment time, the 3D PNCNs demonstrate several remarkable advantages for oxygen reduction reaction (ORR) electrocatalysts, including ultra-high specific surface area (more than 2100 m2/g−1), unique 3D porous structure, abundant defects, and suitable configuration of nitrogen. With these merits, the N-C-2 h based electrocatalyst exhibits outstanding ORR activities with a comparable onset potential of −40 mV (vs. Ag/AgCl), half-wave potential of −120 mV (vs. Ag/AgCl), satisfactory electron transfer number (4) and superior stability to those of commercial 20% Pt/C. The excellent electrochemical behaviors of 3D PNCNs are confirmed to be dominated by structural characteristics, which can be optimized by varying thermal treatment time. Our work offers a promising way for controllably constructing carbon-based materials with optimized ORR performance.

Preparation of diatomite-based SA@ZIF-8 composite microspheres by electrostatic spray method and its adsorption performance for Cu(II)

Diatomite (DE)-based sodium alginate (SA) loaded ZIF-8 composite microspheres were prepared by high-voltage electrostatic spray technology. SA/DE microspheres were prepared by SA and acid-base-regulated silica sol solution. Ultra-small ZIF-8 was grown on SA/DE microspheres by in-situ synthesis method to obtain ultra-high specific surface area composite microspheres. The morphology and particle size of the composite microspheres were analyzed by SEM, and characterized by FT-IR, XRD and TGA. The optimum adsorption efficiency were achieved by a series of conditions optimization. The adsorption of Cu(II) by SA/DE@ZIF-8 conforms to the Langmuir adsorption model, and the theoretical maximum adsorption capacity is 599.07 mg/g. In summary, this study opens up a new strategy for the design of efficient and easily recycled ZIF-8 composite microspheres for water treatment.

Efficient removal of methylene blue via two-step modification hazelnut shell biochar: Process intensification, kinetics and thermodynamics

Porous carbon materials with ultra-high specific surface area and adjustable pore structure characteristics were prepared from food industry waste hazelnut shells for the adsorption of methylene blue (MB) wastewater by two-step activation by impregnation with ZnCl2 followed by chemical activation with KOH. The Fusso effect, which can reduce the size of MB molecules, was further used to enhance the adsorption of MB on porous carbon. The results show that both HSBC-a and HSBC-a-b have ultra-high specific surface area (2979.59 m2/g for HSBC-a, 2882.73 m2/g for HSBC-a-b). The mesopore ratio of HSBC-a-b (Vmeso/Vtotal % = 14.05%) was doubled compared to HSBC-a. It showed an excellent adsorption performance of 694.03 mg/g for MB. It showed a fast adsorption kinetics and the adsorbed amount increased to 882.46 mg/g at 0.1 M NaCl solution. In addition, adsorption processes were studied using adsorption kinetics and adsorption isotherm model fitting. The results of this research confirm that hazelnut shell is a kind of promising and sustainable porous carbon raw material, and its ultra-high specific surface area and adjustable pore structure characteristics are favorable for the efficient treatment of MB from dyeing wastewater. This work could provide potential guidance for the high-value utilization of waste hazelnut shell biochar.

Engineering Active-Site-Induced Homogeneous Growth of Polydopamine Nanocontainers on Loading-Enhanced Ultrathin Graphene for Smart Self-Healing Anticorrosion Coatings

Engineering nanocontainers with encapsulated inhibitors onto graphene has been an emerging technology for developing self-healing anticorrosion coatings. However, the loading contents of inhibitors are commonly limited by inhomogeneous nanostructures of graphene platforms. Here, we propose an activation-induced ultrathin graphene platform (UG-BP) with the homogeneous growth of polydopamine (PDA) nanocontainers encapsulated with benzotriazole (BTA). Ultrathin graphene prepared by catalytic exfoliation and etching activation provides an ideal platform with an ultrahigh specific surface area (1646.8 m2/g) and homogeneous active sites for the growth of PDA nanocontainers, which achieves a high loading content of inhibitors (40 wt %). The obtained UG-BP platform exhibits pH-sensitive corrosion inhibition effects due to its charged groups. The epoxy/UG-BP coating possesses integrated properties of enhanced mechanical properties (>94%), efficient pH-sensitive self-healing behaviors (98.5% healing efficiency over 7 days), and excellent anticorrosion performance (4.21 × 109 Ω·cm2 over 60 days), which stands out from previous related works. Moreover, the interfacial anticorrosion mechanism of UG-BP is revealed in detail, which can inhibit the oxidation of Fe2+ and promote the passivation of corrosion products by a dehydration process. This work provides a universal activation-induced strategy for developing loading-enhanced and tailor-made graphene platforms in extended smart systems and demonstrates a promising smart self-healing coating for advanced anticorrosion applications.

Dual-Salt-Induced Hierarchical Porous Structure in a Carbon Sheet for High Performance Supercapacitors

Porous carbon, one of the characteristic materials for electrochemical energy storage devices, has been paid wide-ranging attention. However, balancing the reconcilable mesopore volume with a large specific surface area (SSA) was still a challenge. Herein, a dual-salt-induced activation strategy was developed to obtain a porous carbon sheet with ultrahigh SSA (3082 m2 g-1), desirable mesopore volume (0.66 cm3 g-1), nanosheet morphology, and high surface O (7.87%) and S (4.0%) content. Hence, as a supercapacitor electrode, the optimal sample possessed a high specific capacitance (351 F g-1 at 1 A g-1) and excellent rate performance (holding capacitance up to 72.2% at 50 A g-1). Furthermore, the assembled zinc-ion hybrid supercapacitor also exhibited superior reversible capacity (142.7 mAh g-1 at 0.2 A g-1) and highly stable cycling (71.2 mAh g-1 at 5 A g-1 after 10,000 cycles with retention of 98.9%). This work was delivered a new possibility for the development of coal resources for the preparation of high performance porous carbon materials.

Polyamide composite membrane with 3D honeycomb-like structure via acetone-regulated interfacial polymerization for high-efficiency organic solvent nanofiltration

High-performance organic solvent nanofiltration (OSN) membranes play an indispensable role in chemical separation processes. However, conventional OSN membranes such as thin-film composite polyamide (TFC-PA) membranes exhibit insufficient perm-selectivity. In this study, we developed a high-performance TFC-PAOSN membrane on a porous polyketone (PK) support by regulating interfacial polymerization (IP) with acetone as an organic co-solvent. The effect of the acetone co-solvent on the IP reaction and PA nanofilm morphology was investigated. Acetone serves as a regulator to mediate the IP reaction by facilitating the convective diffusion of monomers at the aqueous/organic interface. Furthermore, experimental results and molecular dynamics (MD) simulation analysis confirmed that the addition of acetone increases the width of the IP reaction zone, facilitates more violent exothermic reactions, and induces aggravated vaporization of acetone, resulting in the formation of a 3D honeycomb-like structure with an ultrahigh specific surface area. Compared with the TFC-PA membrane prepared by the conventional IP method, the TFC-PA-acetone membrane prepared by acetone-regulated IP (ARIP) exhibited 2.6 times higher methanol solvent permeance (7.0 LMH/bar) and comparable methyl orange rejection (94.6%). This work explores the underlying mechanism of acetone-regulated IP, providing a facile strategy for tailoring the membrane morphology with high-efficiency organic solvent nanofiltration.

Combining 3D Printing and Electrochemical Deposition for Manufacturing Tailor-Made 3D Nickel Foams with Highly Competitive Porosity and Specific Surface Area Density

One of the most promising and heavily researched energy storage systems due to their high energy density, rate capability and extended cycle life are lithium-ion batteries. Their performance and efficiency are nonetheless strongly dependent on their constituent materials and design, including the current collectors. One attractive approach in this respect is the use of metal foams as an alternative to the conventional current collectors. This concept is therefore intended to increase the current collectors’ specific surface area and therefore load more active material by nominal area while keeping the cell architectures simple and less costly. In the present work, nickel is chosen as a model system for a proof of concept of a novel manufacturing method for nickel foams using a combination of 3D printing, coating and electroplating. The purpose is to create geometrically well-defined hollow structures with high porosity and specific surface area density that can rival and partially outperform the commercially available nickel foams. To this end, a 3D printer is used to create geometrically flexible and well-defined open-pored disks of HIPS (high-impact polystyrene), which are then spray coated with a graphite-based conducting layer and subsequently electroplated with a 5–30 µm thin layer of nickel from an additive-free nickel sulfamate electrolyte. Following the coating process, the support structure is dissolved with toluene, resulting in structures with a unique combination of porosity in the range of 92.3–99.1% and an ultra-high specific surface area density up to 46 m2/kg. Morphological characterization by light and scanning electron microscopy has proven that the temporarily required polymer substrate can be mildly and completely removed by the suggested room temperature dissolution process.

The honeysuckle stem derived porous carbon with an ultra-high specific surface area and ultra-long cycle life

The honeysuckle stem derived porous carbon with an ultra-high specific surface area and ultra-long cycle life

Lignin-derived carbon aerogels with high surface area for supercapacitor applications

Carbon materials are attracting increasing interest in the field of supercapacitors because of their well-developed porous structures, large specific surface areas, long cycle life, good conductivity, and environmental friendliness. In this study, Kraft lignin extracted from black liquor was used to synthesize a lignin precursor via the sol–gel method. Under well-controlled pyrolysis conditions, this precursor produces lignin-based carbon aerogels (LECAs) with well-developed textural structures that exhibit excellent supercapacitor performance. A LECA with a specific surface area of 3742 m2 g−1 exhibits a saturated adsorption capacity of up to 3442 mg g−1 for methylene blue. As a supercapacitor electrode material, the LECA shows an excellent specific capacitance (504.7F g−1 at 0.2 A g−1) and a high stability (87.7% capacity retention after 10,000 cycles). In addition, a symmetric LECA-based supercapacitor exhibits high energy and power densities with maximum values of 18.1 Wh kg−1 and 16000 W kg−1, respectively. This excellent energy-storage ability may be attributable to the LECA electrode, which has an ultrahigh specific surface area, suitable pore size distribution, and trace amounts of heteroatoms such as O and S. Thus, this study provides a simple, scalable approach for improving the performance of lignin-based energy-storage materials and offers a route for the high-quality utilization of lignin derived from the pulp and paper industry toward the alleviation of environmental pollution.