Tailored Pore Size Research Articles

Supercapacitor electrodes based on metal‐organic compounds from the first transition metal series

AbstractMetal‐organic compounds, including molecular complexes and coordination polymers, have attracted much attention as electrode materials in supercapacitors owing to their large surface area, high porosity, tailorable pore size, controllable structure, good electrochemical reversibility, and abundant active sites. Among the variety of metal‐organic compounds exhibiting desired supercapacitor performances (high specific capacitance, long cycling life, high energy density, and power density), those with metals in the first transition metal series are the most studied due to their rich covalent states, light atom weight, environmental‐friendliness, non‐toxicity, and low cost. In this review, the recent reports on the metal‐organic compounds of the first transition metal series as electrode materials in supercapacitors are summarized and their electrode and device performances are discussed in terms of different metal elements and typical multidentate ligands. Moreover, the current challenges, design strategies, future opportunities and further research directions are also highlighted for metal‐organic compounds in the field of supercapacitors.image

Soluble salt assisted synthesis of hierarchical porous carbon-encapsulated Fe3C based on MOFs gel for all-solid-state hybrid supercapacitor

Hierarchical porous materials receive extensive attention due to their excellent electrode kinetic performance. Herein, a facile strategy is presented to fabricate hierarchical porous supercapacitor materials using NaCl-assisted MOFs gel as a structure-directing template. By controlling the additive amount of NaCl, hierarchical porous carbon-encapsulated Fe3C with tailored pore size distribution has been obtained with a high specific capacity of 184.1 mAh g−1 (602.3F g−1) at a current density of 1 A g−1. The analysis of kinetics and impedance indicates that the tailored porosity can provide broad ion diffusion pathway and low charge-transfer resistance. Meanwhile, seawater was used instead of NaCl for preparing hierarchical porous carbon with good capacitive performance. When evaluated their practical applications, the assembled all-solid-state hybrid supercapacitor delivers a high energy density of 30.6 W h kg−1 at a power density of 600 W kg−1, and even maintains an energy density of 15.5 W h kg−1 at a power density of 12000 W kg−1 with 86.5% capacity retention after 10,000 cycles. This work is anticipated to open up a new route of using MOFs gel and water-soluble salts for designing hierarchical porous electrodes materials, which pave the way for advanced utilization of MOFs gel and seawater.

Could Nanotheranostics be the Answer to the Coronavirus Crisis?

The COVID‐19 pandemic is expanding worldwide. This pandemic associated with COVID‐19 placed the spotlight on how bacterial (e.g., methicillin‐resistant Staphylococcus aureus) co‐infections may impact responses to coronavirus. In this review the ways in which nanoparticles can contain and rapidly diagnose COVID‐19 under the umbrella of nanotheranostics (i.e., smart, single agents combining nanodiagnostics and nanotherapeutics) are elaborated. The present work provides new insights into the promising incorporation of antiviral nanotheranostics into nanostructured materials, including electrospun fibers with tailored pore sizes and hydrophobicity, namely “superhydrophobic self‐disinfecting electrospun facemasks/fabrics (SSEF).” SSEFs are proposed as smart alternatives to address the drawbacks of N95 respirators. The challenges of coronavirus containment are underscored, literature is reviewed, and “top‐five suggestions” for containing COVID‐19 are offered, including: i) preventive appraisals—avoiding needless hospital admission and practicing frequent hand washing (from 20 to 60 s). ii) Diagnostics—highly recommending nanodiagnostics, detecting COVID‐19 within 10 min. iii) Therapeutics—expanding nanotherapeutics to treat COVID‐19 and bacterial co‐infections after safety assessments and clinical trials. iv) Multipronged and multinational, including China, collaborative appraisals. v) Humanitarian compassion to traverse this pandemic in a united way.

Constructing coral-like hierarchical porous carbon architectures with tailored pore size distribution as sulfur hosts for durable Li-S batteries

Structural hierarchy of porous carbon has been a key role in the sulfur hosts for lithium sulfur (Li-S) batteries. Herein, coral-like hierarchical porous carbon (HPC) is developed by a dual alkaline activation process. The production of HPC is inexpensive and scalable, which gives a great promise as sulfur host for the future application of Li-S batteries. Moreover, the as-prepared material achieves an admirable interconnected conductive network, hierarchical pore size distribution and notably high pore volume. This architecture contributes to ultrafast ion diffusion, rapid mass transport, robust electrode configuration as well as effective physical adsorption for soluble polysulfide, thus enabling a favorable scaffold for Li-S battery cathodes with high sulfur utilization and exceptionally electrochemical stability. As a consequence, the HPC based sulfur cathode manifests high areal capacity of 7.5mAh/cm2 with a high sulfur loading and superb cycling stability over 500 cycles with lower sulfur loading. The classification of alkali significantly affects on the hierarchical porosity of the resultant carbon. And the correlation between the pore size distribution and electrochemical performance is revealed. This work offers a hierarchical material engineering of a sulfur host material for restricting the mobile polysulfide moieties, thus achieving a high efficiency and stable Li-S battery.

Fabrication of trabecular-like beta-tricalcium phosphate biomimetic scaffolds for bone tissue engineering

The introduction of 3D printing into the manufacturing of ceramic components offers new possibilities to fabricate porous bioceramic scaffold with biomimetic morphology, customized-designed shape and suitable mechanical property for bone tissue engineering. However, most of 3D printed porous ceramic scaffolds are prepared from the array of unit cells, which do not exploit the whole potential of additive manufacturing. In this paper, a novel biomimetic porous beta-tricalcium phosphate (β-TCP) scaffolds with trabecular-like morphology were obtained based on three dimension (3D) Voronoi tessellation method and generated design. This bionic pore structure is fabricated via photopolymer-based digital light processing (DLP) 3D printing technique, a suitable 30 wt% β-TCP ceramic slurry with the addition of adjuvants was prepared. After optimized debinding-sintering process according the TG-DSC analysis, the β-TCP scaffolds showed fully interconnected trabecular-like pore structure with tailorable pore size (360 μm–1200 μm) and porosity (45%–75%) and compact microstructure. Combining compressive tests and finite element analysis (FEA), the relationship between inputting parameters, pore structure and compressive strength is investigated. Thus, the mechanical strength of the trabecular-like β-TCP scaffolds could be predicted and tuned in the initial generated design stage. In addition, the shrinkage ratio and XRD pattern are also detected. The method proposed in this study may provide an efficient bionic design intended for tissue engineering applications.

Photothermal-modulated drug release from a composite hydrogel based on silk fibroin and sodium alginate

In order to realize effective controlled release of medicine to specific sites, the near-infrared (NIR) light responsive hydrogel has recently attracted noticeable attention as an innovative vehicle for a reserving and releasing the drug remotely “on demand” via stimuli-responsive NIR irradiation on/off. Herein, a modulated drug delivery platform was developed based on a silk fibroin (SF)/sodium alginate (SA) composite hydrogel incorporated with indocyanine green (ICG) as components. The gelation time of the crosslinked composite hydrogel ranged from 15 to 35 min, mainly depending on the concentration of SF. These materials are typical elastic hydrogels display stiffness between 260 and 2210 Pa. Besides, the compressive modulus E of the hydrogels varied in the range of 0.89–1.71 kPa by changing blend ratios. Scanning electron microscope (SEM) revealed the hydrogels showed highly porous (~89%) and tailored pore size in the range of 132–215 µm. And SF mainly remained silk I structure in the composite hydrogel and bovine serum albumin (BSA) and tetracycline hydrochloride (TH) still kept their own structure after encapsulation. SF/SA@ICG hydrogels exhibited desirable stability and swelling properties. Additionally, these hydrogel extracts displayed good cellular compatibility in vitro. Under near-infrared (NIR) radiation exposure, the hydrogels exhibited photothermal properties such as temperature rise by 8 °C, sufficient to stimulate drug release. Furthermore, hydrogels demonstrated NIR stimulated drug release, which was evaluated using BSA and TH, the drug loaded photothermal hydrogels can effectively increase the amount of drug released under NIR light trigger for just 1 min. The NIR-responsive hydrogels can provide a new option for developing natural ploymer based delivery vehicles to regulate drug release on demond using NIR irradiation remotely.

High-Performance Porous Graphene Oxide Hollow Fiber Membranes with Tailored Pore Sizes for Water Purification

High-Performance Porous Graphene Oxide Hollow Fiber Membranes with Tailored Pore Sizes for Water Purification

Nanoporous carbon oxynitride and its enhanced lithium-ion storage performance

Heteroatom doped nanomaterials are reported to be excellent electrodes for energy storage and conversion applications. However, the introduction of these heteroatoms in materials such as carbon nitride is quite challenging owing to the poor thermodynamic stability of these atoms in the carbon matrix. In this report, we demonstrate the single-step approach for the preparation of highly ordered nanoporous carbon oxynitride (O-MCN) materials with tailored pore sizes by employing carbohydrazide as a single C, N, O precursor using nano-templating approach. Experimental characterization of the O-MCN confirms oxygen doping in C-N framework. Density functional theory (DFT) calculations demonstrate that the O-MCN optimized with AB type bilayer structure can adsorb nine Li ions per unit cell with mild Li-ion binding energy value of 5.16 eV. The synthesized O-MCN materials are firstly applied in Li-ion batteries as anode materials. The optimized O-MCN displays 2.5 times higher reversible capacity than that of non-porous g-C3N4 with remarkable stability in the long run in the Li-ion battery.

Controllable biotransformation of naringin to prunin by naringinase immobilized on functionalized silica

AbstractBACKGROUNDMesoporous silica materials, with high specific surface area, tailorable pore size and excellent chemical stability, have wide prospects for application in catalyst carriers. In this work, aldehyde‐modified silica materials were first prepared through silanization reaction of N‐[3‐(trimethoxysilyl)propyl]ethylenediamine and then Schiff base reaction of glutaraldehyde. Subsequently, the resulting materials were used for immobilization of naringinase.RESULTSThe results demonstrated that the activity of immobilized naringinase was optimized as 352.83 U g−1 support. The optimal immobilization conditions were determined as follows: immobilization temperature of 30 °C, immobilization time of 3 h, pH of 3.5 and initial naringinase activity of 200.75 U mL−1. In addition, at the optimal reaction temperature of 50 °C and pH of 8.0, the percentage of immobilization, naringinase activity recovery and naringinase activity of the immobilized naringinase reached 56.41%, 93.42% and 423.22 U g−1 support, respectively. Besides, comparing with free naringinase, in the process of naringin hydrolysis, the immobilized naringinase exhibited wide pH application range and good thermal stability, and still maintained 71.13% residual naringinase activity after 1 month of storage. Even more important, the immobilized naringinase could controllably transform naringin to prunin as the only hydrolysis product, and no naringenin was detected, which represents a new route for controllable preparation of prunin.CONCLUSIONSThis study provides an ideal carrier material and some basic data for naringinase immobilization technology, which will greatly promote the application of naringinase and the development of the pharmaceutical industry. © 2020 Society of Chemical Industry

Understanding how pore surface fluorination influences light hydrocarbon separation in metal–organic frameworks

The designability and tunability of the pore structure are the advantage of metal–organic frameworks (MOFs) for adsorptive separation applications. However, it is still challenging to design MOF adsorbent rationally according to industrial demands, because of the complexity in the separation processes and the relative lack of structure-separation relationship information. Herein, we established a contrastive model ingeniously via structural modification at the atom level in three Cu(II)-MOFs constructed from isonicotinic acid (HINA) and its fluorinated analogue 3-fluoro-isonicotinic acid (HFINA), targeting on controlling pore surface fluorination for studying light hydrocarbon separation. Both the fluorinated MOFs (Cu-FINA-1 and 2) show notably enhanced C2H2/C2H4 and C3H4/C3H6 selectivity compared with Cu-INA without increasing regeneration energy consumption. Especially, Cu-FINA-2 exhibits a considerable IAST selectivity (6.3–9.3) for C3H4/C3H6, while Cu-FINA-1 achieves a C3H6 process productivity of 31.6 cm3/g in column breakthrough experiments. Molecular simulations reveal that the polar F sites within the confined pores can interact with gas adsorbates through C-H···F hydrogen bonds, and the tailored pore size and optimal diffusion kinetics mainly contribute to the excellent separation selectivity for Cu-FINA-1. This work highlights how pore surface fluorination and related structural evolution can influence light hydrocarbon adsorption/separation properties in MOFs, and thus promotes the rational design and precise optimization of new adsorbents for alkynes/alkenes separations, even at the atom level.

Polyetheresterurethane Based Porous Scaffolds with Tailorable Architectures by Supercritical CO2 Foaming

Porous three-dimensional (3D) scaffolds are promising treatment options in regenerative medicine. Supercritical and dense-phase fluid technologies provide an attractive alternative to solvent-based scaffold fabrication methods. In this work, we report on the fabrication of poly-etheresterurethane (PPDO-PCL) based porous scaffolds with tailorable pore size, porosity, and pore interconnectivity by using supercritical CO2 (scCO2) fluid-foaming. The influence of the processing parameters such as soaking time, soaking temperature and depressurization on porosity, pore size, and interconnectivity of the foams were investigated. The average pore diameter could be varied between 100-800 μm along with a porosity in the range from (19 ± 3 to 61 ± 6)% and interconnectivity of up to 82%. To demonstrate their applicability as scaffold materials, selected foams were sterilized via ethylene oxide sterilization. They showed negligible cytotoxicity in tests according to DIN EN ISO 10993-5 and 10993-12 using L929 cells. The study demonstrated that the pore size, porosity and the interconnectivity of this multi-phase semicrystalline polymer could be tailored by careful control of the processing parameters during the scCO2 foaming process. In this way, PPDO-PCL scaffolds with high porosity and interconnectivity are potential candidate materials for regenerative treatment options.

Sustainable Carbon as Efficient Support for Metal-Based Nanocatalyst: Applications in Energy Harvesting and Storage.

Sustainable activated carbon can be obtained from the pyrolysis/activation of biomass wastes coming from different origins. Carbon obtained in this way shows interesting properties, such as high surface area, electrical conductivity, thermal and chemical stability, and porosity. These characteristics among others, such as a tailored pore size distribution and the possibility of functionalization, lead to an increased use of activated carbons in catalysis. The use of activated carbons from biomass origins is a step forward in the development of more sustainable processes enhancing material recycling and reuse in the frame of a circular economy. In this article, a perspective of different heterogeneous catalysts based on sustainable activated carbon from biomass origins will be analyzed focusing on their properties and catalytic performance for determined energy-related applications. In this way, the article aims to give the reader a scope of the potential of these tailor-made sustainable materials as a support in heterogeneous catalysis and future developments needed to improve catalyst performance. The selected applications are those related with H2 energy and the production of biomethane for energy through CO2 methanation.

Bioinspired "Skin" with Cooperative Thermo-Optical Effect for Daytime Radiative Cooling.

Energy-saving cooling materials with strong operability are desirable for sustainable thermal management. Inspired by the cooperative thermo-optical effect in the fur of a polar bear, we develop a flexible, superhydrophobic, and reusable cooling "skin" by laminating a poly(dimethylsiloxane) film with a highly scattering polyethylene aerogel. Owing to its high porosity (97.9%) and tailored pore size of 3.8 ± 1.4 μm, it can achieve superior solar reflectance (R̅sun ∼ 0.96) and high transparency to irradiated thermal energy (τ̅PE,MIR ∼ 0.8) at a thickness of 2.7 mm. Combined with the low thermal conductivity (0.032 W m-1 K-1) of the aerogel, the cooling skin exerts midday sub-ambient temperature drops of 5-6 °C in a metropolitan environment, with an estimated limit of 14 °C under ideal service conditions. Our generalized bilayer approach can be easily applied to different types of emitters, bridging the gap between night-time and daytime radiative cooling and paving the way for more cost-effective and scalable cooling materials.

Hierarchical H-ZSM5 zeolites based on natural kaolinite as a high-performance catalyst for methanol to aromatic hydrocarbons conversion

The present work introduces a good prospect for the development of hierarchical catalysts with excellent catalytic performance in the methanol to aromatic hydrocarbons conversion (MTA) process. Hierarchical H-ZSM5 zeolites, with a tailored pore size and different Si/Al ratios, were synthesized directly using natural kaolin clay as a low-cost silica and aluminium resource. Further explored for the direct synthesis of hierarchical HZSM-5 structures was the steam assisted conversion (SAC) with a cost-effective and green affordable saccharide source of high fructose corn syrup (HFCS), as a secondary mesopore agent. The fabricated zeolites exhibiting good crystallinity, 2D and 3D nanostructures, high specific surface area, tailored pore size, and tunable acidity. Finally, the catalyst performance in the conversion of methanol to aromatic hydrocarbons was tested in a fixed bed reactor. The synthesized H-ZSM5 catalysts exhibited superior methanol conversion (over 100 h up to 90%) and selectivity (over 85%) in the methanol conversion to aromatic hydrocarbon products.

Fabricating efficient porous sorbents to capture organophosphorus pesticide in solution

Abstract The adsorption of organophosphorus pesticides in aqueous solution was studied in this paper, including acephate, folimat, phoxim, chlorpyrifos, dipterex, and two other pesticides carbendazim and imidacloprid. Sixteen sorbents were used in the experiments, involving zeolites, mesoporous silica and activated carbon, in order to explore how the pore structure, morphology and surface composition of the sorbent affected the liquid adsorption. Among them, MCM-22 zeolite and modified SBA-15 exhibited a high capacity of capturing carbendazim and dipterex in the solution. In order to prepare a new adsorbent with low cost and high efficiency, silica gel was coated with MgO followed by alkali corrosion, in accordance with the principle of printed circuits, to form the micro-porous sorbent with the tailored pore size and surface composition. This modified silica efficiently adsorbed the folimat and rogor in solution as expected, giving a clue for the development of specific sorbent to protect environment.

Ordered Nanoporous Carbons with Broadly Tunable Pore Size Using Bottlebrush Block Copolymer Templates.

We report the preparation of ordered porous carbon materials with tailored pore sizes selected between 16 and 108 nm using bottlebrush block copolymers (BBCPs) as templates. The nanoporous carbons are prepared via the cooperative assembly of polydimethylsiloxane-block-poly(ethylene oxide) (PDMS-b-PEO) BBCPs with phenol-formaldehyde resin yielding ordered precursor films, followed by carbonization. The assembly of PDMS-b-PEO BBCPs with the resin leads to films exhibiting a spherical morphology (PDMS as the minor domain) with uniform domain sizes between 18 and 150 nm in the bulk. The assembled PDMS sphere diameters scale linearly with BBCPs molecular weights, allowing precise control of domain size. Access to very large ordered domains is an enabling hallmark of BBCPs self-assembly, but reports of well-ordered spherical domains are not common. Carbonization of the ordered precursor films yields nanoporous carbon with uniform and tunable pore size. These nanoporous carbons are shown to exhibit excellent performance as supercapacitor electrodes with capacitance reaching up to 254 F g-1 at a current density of 2 A g-1.

Metal-organic frameworks and their derivatives for Li–air batteries

Metal-organic frameworks (MOFs) are a class of outstanding materials in Li–air batteries because of their high surface areas, tailorable pore sizes and diverse catalytic centers. However, MOF-based batteries are facing challenges such as poor electronic conductivity and inferior long-cycle stability that limit their further development. This review first summarizes the progress of pristine MOFs and MOF-derived materials in Li–air batteries in the past 5 years, then provides a perspective for subsequent development of MOFs and their derivatives in this emerging field.

V‐N‐C catalysts anchored to mesoporous Al‐SBA‐15 with tailorable pore sizes for the synthesis of spirooxindole dihydroquinazolinones derivatives

Heterogeneous nanoscale catalyst was successfully synthesized via anchoring of V‐bis(2‐aminobenzamide) complex on the Al‐SBA‐15. This modified mesoporous was identified by several characterization techniques, such as X‐ray diffraction, field emission‐scanning electron microscopy, Fourier transform‐infrared, Brunauer–Emmett–Teller and transmission electron microscopy. V‐Bis(2‐aminobenzamide)@Al‐SBA‐15 was found to be an efficient heterogeneous catalyst for the rapid and desirable synthesis of various spirooxindole dihydroquinazolinones derivatives. In addition, the heterogeneous nanocatalyst was chemically stabilized in organic and aqueous solutions as well as can be expeditiously reused for at least seven cycles without a significant loss in catalytic activity.

Efficient bio-ethanol recovery by non-contact vapor permeation process using membranes with tailored pore size and hydrophobicity

Vapor permeation seems to be a more suitable separation process than pervaporation in bio-ethanol recovery from fermentation broth because of its non-direct contact trait. The unsatisfactory flux and selectivity of polymeric membranes limit their utilization in industrial application. Here, we tailored the physical and chemical structure of commercial available polyacrylonitrile (PAN) ultrafiltration membrane to serve in vapor permeation. The membrane porosity was reduced till dense enough for separation while preserving an ultra-high flux by hydrolyzing in alkali. The hydrophilicity/hydrophobicity was controlled by grafting fluoroalkyl chains to ensure an acceptable ethanol selectivity. The changes of physical structure and chemical property were systematically characterized by Fourier transform infrared-attenuated total reflectance (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), water contact angle and pure water permeance. Tested at 60 °C, the optimized membrane exhibited a high flux of ca. 10.5 kg m−2 h−1 and a permeate ethanol content similar to vapor-liquid equilibrium curve, which outstripped most polymeric membranes (applied in pervaporation or vapor permeation) in both flux and selectivity.

Celgard-silica composite membranes with enhanced wettability and tailored pore sizes prepared by supercritical carbon dioxide assisted impregnation with silanes

In this work, a novel method of producing polyolefin-silica composite membrane with enhanced wettability and tailored pore sizes was presented. The supercritical CO2 was used as the medium for intercalation of the silica precursor into the polymer matrix, which allowed obtaining a uniform distribution of SiO2 nanoparticles in the material structure. The proposed method of impregnating Celgard matrix with tetraethoxysilane (TEOS) in supercritical carbon dioxide and following acid-catalyzed hydrolysis and condensation leads to significant changes in ion transport properties of Celgard membranes in aqueous electrolytes. This allows one to obtain separators suitable for aqueous electrochemical energy storage systems such as aqueous vanadium redox flow batteries.