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Lithium–sulfur batteries (LSBs) have emerged as promising power sources for high‐performance devices such as electric vehicles. However, the poor energy density of LSBs owing to polysulfide shuttling and passivation has limited their further market penetration. To mitigate this challenge, two‐dimensional (2D) siloxene (2DSi), a Si‐based analog of graphene, is utilized as an additive for sulfur cathodes. The 2DSi is fabricated on a large scale by simple solvent extraction of calcium disilicide to form a thin‐layered structure of Si planes functionalized with vertically aligned hydroxyl groups in the 2DSi. The stoichiometric reaction of 2DSi with polysulfides generates a thiosulfate redox mediator, secures the intercalation pathway, and reveals Lewis acidic sites within the siloxene galleries. The 2DSi utilizes the corresponding in‐situ‐formed electrocatalyst, the 2D confinement effect of the layered structure, and the surface affinity based on Lewis acid–base interaction to improve the energy density of 2DSi‐based LSB cells. Combined with the commercial carbon‐based current collector, 2DSi‐based LSB cells achieve a volumetric energy density of 612 Wh Lcell−1 at 1 mA cm−2 with minor degradation of 0.17% per cycle, which rivals those of state‐of‐the‐art LSBs. This study presents a method for the industrial production of high‐energy‐dense LSBs.

This work was financially supported by and Chonnam National University, 2016 and the RD No. 2019R1C1C1007745, the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science, ICT & Future Planning; No. 2019R1A4A2001527).

Solar-energy-driven water purification is a promising technology for obtaining clean water during the current global climate crisis. Solar absorbers with high light absorption capacity and efficient energy conversion are critical components of solar-driven water evaporation and purification systems. Herein, we demonstrate that porous reduced graphene oxide (rGO)-based composite spheres facilitate efficient water evaporation and effective organic pollutant adsorption from water. Most solar light (>99% for 1 mm thick composites) is absorbed by the porous rGO-based composite spheres floating on water and is subsequently converted into heat, which is efficiently transferred to water at the air-water interface. Evaporation efficiency via energy conversion by the floating sphere composites reaches ∼74%. The increase in surface temperature of water also contributes to improving the adsorption capacity of the rGO-based composite spheres for organic pollutants. Furthermore, the composites can effectively block ultraviolet radiation, preventing the chemical reaction of water pollutants into harmful components.

The fluids of fascinating nanomaterials have recently been reported to exhibit liquid crystalline (LC) phases, and these mesophases have attracted significant interest in both fluid physics and cutting-edge applications; graphitic carbon nitride (g-CN), a type of 2D semiconducting polymers, has gained significant attention in recent years for optoelectronic and catalytic applications. However, g-CN has been studied on a powder material, which suffers from limited dispersibility, difficult recovery, and low surface accessibility. In this study, we report that controlled g-CN, which has high-aspect ratio and expanded interlayer spacing, can exhibit its true LC phase in concentrated sulfuric acid. By utilizing its LC phase, more importantly, we could fabricate a g-CN fiber for the first time.

Large particulate photocatalysts allow efficient recovery or installation into the substrate, while limiting possible light-catalyst interaction or mass/charge-transfer. In this study, we developed monodisperse organic single-crystal monoliths with controllable dimensions in the range of 10–100 μm. These were prepared on a 10-g scale by a solution-processed molecular cooperative assembly between melamine (M) and trithiocyanuric acid (TCA) and then transformed into the corresponding g-CN (MTCA-CN) by thermal polycondensation. Molecular precursors that are tightly bound in the crystal undergo polycondensation without losing their macroscopic properties depending on the dimensions of MTCA, thereby changing the microstructure, electronic structure, and photocatalytic activity. Such dimensional tunability enables the fulfillment of various catalytic requirements such as particle size, light absorption, charge separation, band edge potential, and mass transfer. As a proof-of-concept, it was shown that MTCA-CN is tailored to have a high rate of evolution of hydrogen (3.19 μmol/h) from glucose via photoreforming under AM1.5G by using MTCA-100 crystals, leading to the formation of g-CN with the more positive highest occupied molecular orbital (HOMO) level. This study highlights the possibility of developing photocatalysts for practical use and obtaining value-added products (VAPs) without losing the photocatalytic activity relevant for wastewater treatment.

In this study, sludges generated from Ti-based flocculation of dye wastewater were used to retrieve photoactive titania (S-TiO

For the purpose of atmospheric NO removal, anatase TiO

We report an electrochemical sensor based on three-dimensional porous amorphous carbon (3DPAC) for the sensitive and selective determination of gallic acid (GA). The tailor-made carbon was prepared via salt-templating in which the organic molecular precursor, i.e., glucose, was simply ground and carbonized with a eutectic mixture of LiBr and KBr at 800 °C in an inert atmosphere. Salt removal from the carbon-salt mixture with water yielded 3DPAC with a hierarchical porous structure and oxygen-containing functional groups. When employed as an electrochemical sensor, 3DPAC exhibited remarkable sensitivity (0.1045 µA pM−1 cm−2) with a lower detection limit of 0.434 pM at a signal-to-noise ratio of 3 and a linear response up to 1–150 pM for determination of GA. Under optimized test conditions, 3DPAC showed a superior peak current response for GA as compared to the glassy carbon electrode. In addition, ascorbic, uric, and caffeic acids did not interfere with the voltammetric detection of GA in terms of selectivity, stability, and repeatability. We envision that 3DPAC can provide a promising platform for the development of electrochemical sensors.

A polymer hydrogel composed of alginate/humic acid/Fe-aminoclay was fabricated and utilized as a potential adsorbent for the removal of strontium ions (Sr 2 + ) from aqueous solution. The effects of adsorbate concentration, reaction pH, and time on the removal efficiency of Sr 2 + were investigated. The results revealed that the adsorption capacity increases as the Sr 2 + concentration increased from 1 to 10 ppm, which might be due to the more available adsorption sites. An additional increase in the Sr 2 + concentration had no effect. The optimal pH and reaction time for the removal of Sr 2 + were identified as pH 7 and 24 h, respectively, with an adsorbent dosage of 20 mg. The adsorption isotherm was fitted to the Freundlich model with a maximum Sr 2 + adsorption capacity of 45.65 mg g−1. The kinetic study showed that the adsorption behavior followed a pseudo-second-order kinetics. The hydrogel showed good selectivity toward Sr 2 + even in the presence of competitive cations having a higher concentration than Sr 2 + . From the above results, it is expected that this biocompatible hydrogel material can be used as an adsorbent for the removal of radioactive strontium.

To prevent global warming, ESS development is in progress along with the development of electric vehicles and renewable energy. However, the state-of-the-art technology, i.e., lithium-ion batteries, has reached its limitation, and thus the need for high-performance batteries with improved energy and power density is increasing. Lithium-sulfur batteries (LSBs) are attracting enormous attention because of their high theoretical energy density. However, there are technical barriers to its commercialization such as the formation of dendrites on the anode and the shuttle effect of the cathode. To resolve these issues, a boron nitride nanotube (BNNT)-based separator is developed. The BNNT is physically purified so that the purified BNNT (p−BNNT) has a homogeneous pore structure because of random stacking and partial charge on the surface due to the difference of electronegativity between B and N. Compared to the conventional polypropylene (PP) separator, the p−BNNT loaded PP separator prevents the dendrite formation on the Li metal anode, facilitates the ion transfer through the separator, and alleviates the shuttle effect at the cathode. With these effects, the p−BNNT loaded PP separators enable the LSB cells to achieve a specific capacity of 1429 mAh/g, and long-term stability over 200 cycles.

The poor absorption of visible light and rapid recombination of photoexcited charge carriers are the two main factors responsible for the low photocatalytic activities of g-CN under sunlight. To mitigate these technical challenges, we utilize molten-salt synthesis based on alkali metal iodide. The high reactivity of LiI/KI does not allow the polycondensation of triazine dicyanamide intermediates further into PTI, the degree of which depends on the initial weight ratio of eutectic mixture to molecular precursor. This enables the controlled introduction of cyano functional groups with K+-coordination and decomposition of tri-s-triazine into triazine. The resulting all-in-one g-CN-I displays a photocatalytic hydrogen evolution reaction rate of 147 and 60 μmol/h from water under visible light and sunlight, respectively, which are 76 and 7 times higher than those of bulk g-CN. This study demonstrates the significant improvement in the photocatalytic activity of g-CN achievable through the synergistic combination of structural functionalities.

In this study, sludges generated from Ti-based flocculation of dye wastewater were used to retrieve photoactive titania (S–TiO2). It was heterojunctioned with graphitic carbon nitride (g-CN) to augment photoactivity under UV/visible light irradiance. Later the as-prepared samples were utilized to remove nitrogen oxides (NOx) in the atmospheric condition through photocatalysis. Heterojunction between S–TiO2 and g-CN was prepared through facile calcination (@550 °C) of S–TiO2 and melamine mix. Advanced sample characterization was carried out and documented extensively. Successful heterojunction was confirmed from the assessment of morphological and optical attributes of the samples. Finally, the prepared samples’ level of photoactivity was assessed through photooxidation of NOx under both UV and visible light irradiance. Enhanced photoactivity was observed in the prepared samples irrespective of the light types. After 1 h of UV/visible light-based photooxidation, the best sample STC4 was found to remove 15.18% and 9.16% of atmospheric NO, respectively. In STC4, the mixing ratio of S–TiO2, to melamine was maintained as 1:3. Moreover, the optical bandgap of STC4 was found as 2.65 eV, where for S–TiO2, it was 2.83 eV. Hence, the restrained rate of photogenerated charge recombination and tailored energy bandgap of the as-prepared samples were the primary factors for enhancing photoactivity.

AgPd alloy nanoparticles deposited on carbon nitride have been synthesized by a facile one-step reduction method and exhibit high catalytic activity at near room temperature (30 °C) for formic acid dehydrogenation, both under visible light and in darkness. The study proves that using the synergistic combination of alloying effects and metal-support interactions greatly enhances the catalytic activity of Pd-based nanocatalysts for hydrogen generation.

The growing demand for rechargeable batteries with high energy density has triggered research on batteries based on polyvalent cations such as Ca

Although sodium hybrid capacitors (NHCs) have emerged as one of the most promising next-generation energy storage systems, further advancement is delayed primarily by the absence of high-performance battery-type anodes. Herein, we report a nature-inspired synthesis route to prepare hard carbon anodes with high capacity, rate capability, and cycle stability for dual-carbon NHCs. Shape- and size-controllable crystal aggregates of inexpensive triazine molecules are utilized as reactive templates that perform triple duties of structure-directing agent, porogen, and nitrogen source. This enables the fine control of microstructure/morphology/composition and thereby electrochemical reactions toward Na-ion. The resulting hard carbon optimized in terms of lateral size, interlayer spacing, and surface affinity of graphene-like layers achieves a specific capacity of ∼380 mAh/g after 100 cycles at a current density of 250 mA/g mainly

A series of N-doped mesoporous carbon (NMC) materials are synthesized by the co-pyrolysis of an N-containing compound and carbon sources using a modified nanocasting method. The physicochemical properties are manipulated by changing the amount of resol precursors to permit the usage of these materials in the desired applications. As anodes for Li-ion batteries, the prepared NMC2, which has the highest number of hydrogenated N functional groups, delivers a high discharge capacity of 900, 700, and 600 mAh g−1 at current densities of 0.5, 1, and 2 A g−1, respectively, after 200 cycles of discharging and charging. Even at an extremely high current density of 10 A g−1, the NMC2 electrode delivers a discharge capacity of 300 mA g−1. In addition, in Na-ion batteries, NMC3, which has the highest pyridinic N content and average pore diameters, exhibits a discharge capacity of 163 mAh g−1 at 1 A g−1 over 500 cycles. Hence, an intimate relationship between the key physicochemical parameters and electrochemical properties of NMC materials are established for use of these materials in specific applications. The obtained results demonstrate that the fabricated NMC materials possess superior characteristics in comparison to those of most state-of-the-art porous carbon materials.

For the purpose of atmospheric NO removal, anatase TiO2/g-CN photocatalytic composites were prepared by using a facile template-free calcination route in atmospheric conditions. Considerably fiscal NP400 and laboratory-grade melamine were used as the precursor of the composites. Additionally, samples were prepared with different wt. ratios of TiO2 and melamine by using two distinct calcination temperatures (550 °C/600 °C). The morphological attributes of the composites were assessed with X-ray diffraction, scanning and transmission electron microscopy, infrared spectroscopy, and X-ray photoelectron spectroscopy. Additionally, the optical traits were evaluated and compared using UV–visible diffuse reflectance spectroscopy and photoluminescence analysis. Finally, the photodegradation potentials for atmospheric NO by using the as-prepared composites were assessed under both UV and visible light irradiation. All the composites showed superior NO oxidation compared to NP400 and bulk g-CN. For the composites prepared by using the calcination temperature of 550 °C, the maximum NO removal was observed when the NP400 to melamine ratio was 1:2, irrespective of the utilized light irradiation type. Whereas for increased calcination temperature (600 °C), the maximum NO removal was observed at the precursor mix ratio of 1:3 (NP400:melamine). Successfully narrowed energy bandgaps were perceived in the as-prepared composites. Moreover, a subsequent drop in NO2 generation during NO oxidation was observed under both UV and visible light irradiation. Interestingly, higher calcination temperature during the synthesis of the catalysts has shown a significant drop in NO2 generation during the photodegradation of NO.

A 3D cubic structure of mesoporous graphitic carbon nitride (3D-g-CN) was fabricated by nano casting using the mesoporous silica hard template KIT-6. The abundant intrinsic amine functionalities of 3D-g-CN were applied as a selective adsorbent for silver ions using the unique affinity of silver and amine functionalities. The large surface area of 3D-g-CN resulted in increased amine functionalities at the surface and enabled it to form complexes with silver ions. As a result, almost 400 mg/g of silver ion could be removed from 100 mM of initial solution at 293.15 K. The isotherm of silver ion adsorption onto 3D-g-CN was described by the Freundlich and Sips models and indicated heterogeneity of the adsorbent surface. Thermodynamic parameters determined from temperature dependent isotherms were verified by the endothermic silver ion adsorption process of 3D-g-CN. The adsorption capacity of silver ion on 3D-g-CN was maintained during several reuses without a significant decrease in capacity. Overall, the results indicate that 3D-g-CN has intrinsic amine functional groups with a large surface area and could therefore be utilized as an efficient selective adsorbent of silver ions for water purification.

Graphitic carbon nitride (g-C3N4) is widely considered as a promising visible-driven photocatalyst. It is a type of inexpensive, air-stable, and non-toxic material that has been proven to exhibit high performance in photocatalysis. For more efficient use of solar energy, it is necessary to enhance the light absorption of g-C3N4. To take advantage of the near-infrared (NIR) region of the solar energy, g-C3N4 was combined with upconversion nanoparticles (UCNPs), in this study. The UCNPs can convert NIR photons into ultraviolet (UV) and visible light, which can then activate the g-C3N4 photocatalyst. The use of visible and NIR light sources improves the photocatalytic activity of the UCNPs/g-C3N4 nanocomposite. In order to optimize the photocatalytic efficiency of the nanocomposite, the absorption and emission wavelengths of the UCNPs were tuned by controlling the lanthanide dopant composition where the core UCNPs were coated with an inner active shell and an outer inert shell. It is shown in this study that the nanocomposite can exhibit excellent photocatalytic activities under simulated solar light illumination.

Bacterial pathogens of water origin have potential public threats thus suggesting the need of developing efficient and sustainable water disinfection strategies from waterborne pathogens. We set out to synthesize different controlled morphologies of graphitic carbon nitride (g-C

We propose a nanostructured Mn-doped V2O5 lithium-ion battery cathode material that facilitates cathodic charge transport. The synthesis strategy uses a layered compound, vanadium(III) jarosite, as the precursor, in which the Mn2+ ions are doped uniformly between the vanadium oxide crystal layers. Through a two-step transformation, the vanadium jarosite was converted into Mn2+-doped V2O5. The resulting aliovalent doping of the larger Mn cations in the modified V2O5 structure increases the cell volume, which facilitates diffusion of Li+ ions, and introduces oxygen vacancies that improve the electronic conductivity. Comparison of the electrochemical performance in Li-ion batteries of undoped and the Mn2+-doped V2O5 hierarchical structure made from layered vanadium jarosite confirms that the Mn-doping improves ion transport to give a high cathodic columbic capacity (253 mAhg–1 at 1C, 86% of the theoretical value, 294 mAhg–1) and excellent cycling stability.

A high-yielding synthesis of a series of polyimide dendrimers, including decacyclene- and perylene-containing dendrimer D6, in which two types of polyimide dyes are present, is reported. In these constructs, the branching unit is represented by trisphenylamine, and the solubilizing chains by N-9-heptadecanyl-substituted perylene diimides. The photophysical properties of the dendrimers have been studied by absorption, steady-state, and time-resolved emission spectroscopy and pump–probe transient absorption spectroscopy. Photoinduced charge-separated (CS) states are formed on the femtosecond timescale upon visible excitation. In particular, in D6, two different CS states can be formed, involving different subunits that decays independently with different lifetimes (ca. 10–100 ps).

We report utilization of graphitic carbon nitride (g-CN) as an electrocatalyst for dye-sensitized solar cells (DSSCs). Crystalline poly(triazine imide) based g-CN was synthesized via a modified ionothermal method, and deposited onto the counter electrodes along with a conductive additive and a sacrificial polymer binder. The resulting DSSCs exhibited a power conversion efficiency (7.8%) comparable to that of conventional Pt catalyst (7.9%), confirming the excellent catalytic activity of poly(triazine imide) g-CN as a non-precious metal electrocatalyst.

Organic graphitic carbon nitride nanoparticles (NP-g-CN), less than 30 nm in size, were synthesized and evaluated for photodynamic therapy (PDT) and cell imaging applications. NP-g-CN particles were prepared through an intercalation process using a rod-like melamine-cyanuric acid adduct (MCA) as the molecular precursor and a eutectic mixture of LiCl-KCl (45:55 wt%) as the reaction medium for polycondensation. The nano-dimensional NP-g-CN penetrated the malignant tumor cells with minimal hindrance and effectively generated reactive oxygen species (ROS) under visible light irradiation, which could ablate cancer cells. When excited by visible light irradiation (λ > 420 nm), NP-g-CN introduced to HeLa and cos-7 cells generated a significant amount of ROS and killed the cancerous cells selectively. The cytotoxicity of NP-g-CN was manipulated by altering the light irradiation and the BP-g-CN caused more damage to the cancer cells than normal cells at low concentrations. As a potential non-toxic organic nanomaterial, the synthesized NP-g-CN are biocompatible with less cytotoxicity than toxic inorganic materials. The combined effects of the high efficacy of ROS generation under visible light irradiation, low toxicity, and bio-compatibility highlight the potential of NP-g-CN for PDT and imaging without further modification.

Although numerous research efforts have been made for the last two decades, the chronic problems of lithium-sulphur batteries (LSBs), i.e., polysulfide shuttling of active sulphur material and surface passivation of the lithium metal anode, still impede their practical application. In order to mitigate these issues, we utilized polyimide functionalized glass microfibers (PI-GF) as a functional separator. The water-soluble precursor enabled the formation of a homogenous thin coating on the surface of the glass microfiber (GF) membrane with the potential to scale and fine-tune: the PI-GF was prepared by simple dipping of commercial GF into an aqueous solution of poly(amic acid), (PAA), followed by thermal imidization. We found that a tiny amount of polyimide (PI) of 0.5 wt.% is more than enough to endow the GF separator with useful capabilities, both retarding polysulfide migration. Combined with a free-standing microporous carbon cloth-sulphur composite cathode, the PI-GF-based LSB cell exhibits a stable cycling over 120 cycles at a current density of 1 mA/cm2 and an areal sulphur loading of 2 mgS/cm2 with only a marginal capacity loss of 0.099%/cycle. This corresponds to an improvement in cycle stability by 200%, specific capacity by 16.4%, and capacity loss per cycle by 45% as compared to those of the cell without PI coating. Our study revealed that a simple but synergistic combination of porous carbon supporting material and functional separator enabled us to achieve high-performance LSBs, but could also pave the way for the development of practical LSBs using the commercially viable method without using complicated synthesis or harmful and expensive chemicals.

Bacterial pathogens of water origin have potential public threats thus suggesting the need of developing efficient and sustainable water disinfection strategies from waterborne pathogens. We set out to synthesize different controlled morphologies of graphitic carbon nitride (g-C3N4) polymer, evaluate their comparative effects on the generation of reactive oxygen species (ROS), and investigate potential applications in water purification systems. Characterization of the synthesized microstructures of g-C3N4, such as melamine-cyanuric acid (MCA)-based rosette-type, rod-type, 2D hexagonal, and 3D cubic mesoporous silica was accomplished using Fourier transform infrared (FT-IR), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and transmission electron microscopy (TEM). The microbial inhibitory potential of 2D g-C3N4 photocatalyst against waterborne Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium was evaluated based on the effective activity of 2D g-C3N4 upon visible light excitations. The microbicidal efficiency of 2D g-C3N4 was evident within 30 min of visible light exposure via direct interaction, while other microstructures of g-C3N4 demonstrated only slight antimicrobial effects after 120 min, with insufficient ROS generation. The antimicrobial and ROS-generating effects of 2D g-C3N4 depended on the type and surface area of the synthesized 2D g-C3N4 material. Considering its availability and excellent disinfection activity, 2D g-C3N4 obtained from simple and convenient facile synthesis is a promising solar-driven photocatalyst for clearing microbial contamination from water.

Simple organic cooperative assembly of triazine molecules leads to three-dimensional macroscopic assemblies of low-dimensional graphitic carbon nitrides (g-CNs), for example, nanoparticles, nanotubes, and nanosheets. The approach enables the characterization of the cooperative properties and photocatalytic activities of low-dimensional g-CN materials in hydrogen evolution reactions from water under visible light. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Graphitic carbon nitride (g-CN) is a promising heterogeneous metal-free catalyst for organic photosynthesis, solar energy conversion, and photodegradation of pollutants. Its catalytic performance is easily adjustable by modifying texture, optical, and electronic properties via nanocasting, doping, and copolymerization. However, simultaneous optimization has yet to be achieved. Here, a facile synthesis of mesoporous g-CN using molecular cooperative assembly between triazine molecules is reported. Flower-like, layered spherical aggregates of melamine cyanuric acid complex (MCA) are formed by precipitation from equimolecular mixtures in dimethyl sulfoxide (DMSO). Thermal polycondensation of MCA under nitrogen at 550 °C produces mesoporous hollow spheres comprised of tri-s-triazine based g-CN nanosheets (MCA-CN) with the composition of C3N4.14H1.98. The layered structure succeeded from MCA induces stronger optical absorption, widens the bandgap by 0.16 eV, and increases the lifetime of photoexcited charge carriers by twice compared to that of the bulk g-CN, while the chemical structure remains similar to that of the bulk g-CN. As a result of these simultaneous modifications, the photodegradation kinetics of rhodamine B on the catalyst surface can be improved by 10 times.

Uncontrolled hemorrhage is a leading cause of potentially preventable death. The most effective commercial hemostatic products employ layered clays. Due to safety concerns only a product containing kaolin is currently recommended by the U. S. Department of Defense. A problem related to layered clays, including kaolin, is their cytotoxicity. Also, material left in the wound can lead to thrombosis and other adverse effects. Recently, it has been shown that pure silica mesocellular foams (MCF) with cell window sizes >20 nm are effective in promoting blood clotting. Here, we tested the potency and cytotoxicity of layered clays in comparison to MCF with a cell window size of 26 nm (MCF-26) in vitro. The results showed that the potencies of MCF-26 and layered clays in promoting clotting were comparable. Effects on cell viability were assessed with relevant primary human cell types. The cytotoxic effects of all compounds were cell type-specific and most sensitive were endothelial cells. The IC50 values of MCF-26 were in the mg ml−1 range and its cytotoxicity was ∼1–2 orders of magnitude lower than the cytotoxicity of layered clays. Further, MCF-26 did not adhere strongly to cell surfaces and was not taken up by cells as observed for the layered clays. This suggests that it would be easier to remove MCF-26 from wounds. Altogether, the results suggest that MCF-26 would be effective and safer than currently used hemostatic agents.

The technical features of solid-electrode batteries (e.g., high energy density, relatively low capital cost ($/kWh)) and flow batteries (e.g., long cycle life, design flexibility) are highly complementary. It is therefore extremely desirable to integrate their advantages into a single storage device for large-scale energy storage applications where lifetime cost ($/kW-h/cycle) is an extremely important parameter. Here, we demonstrate a non-Li-based-flow battery concept that replaces the aqueous solution of redox-active molecules found in typical redox flow batteries with suspensions of hydrophilic carbon particles ("solid suspension electrodes") coated with earth-abundant redox-active metals. The solid suspension electrodes charge by depositing earth-abundant redox-active metals onto the carbon particle suspension, which are then stripped during discharge operation. The electrical contact to the solid suspension electrodes is fed through fixed redox-inert hydrophobic carbon current collectors through "contact charge transfer" mechanism. The hydrophobicity of the current collectors prevents direct plating of redox-active metals onto their surfaces. The above concept was successfully used to demonstrate several non-Li-based battery chemistries including zinc-copper, zinc-manganese oxide, zinc-bromine, and zinc-sulfur, providing a pathway for potential applications in medium and large-scale electrical energy storage.

Nanostructured uniformly Mn-doped V2O5 Li on battery cathode material is prepared via layered VIII jarosite as precursor, which is obtained by microwave-assisted solvothermal reaction of VOSO4, Mn(OAc)2, and glucose in a H2O/1-hexanol emulsion containing cetyltrimethylammoniumbromide (sealed vial, 195 °C, 1 h) followed by vacuum annealing (900 °C, 1 h) and firing in air (400 °C, 1 h) to convert V2O3 into V2O5.

For practical application of lithium–sulfur batteries (LSBs), it is crucial to develop sulfur cathodes with high areal capacity and cycle stability in a simple and inexpensive manner. In this study, a carbon cloth infiltrated with a sulfur-containing electrolyte solution (CC-S) was utilized as an additive-free, flexible, high-sulfur-loading cathode. A freestanding carbon cloth performed double duty as a current collector and a sulfur-supporting/trapping material. The active material in the form of Li2S6 dissolved in a 1 M LiTFSI-DOL/DME solution was simply infiltrated into the carbon cloth (CC) during cell fabrication, and its optimal loading amount was found to be in a range between 2 and 10 mg/cm2 via electrochemical characterization. It was found that the interwoven carbon microfibers retained structural integrity against volume expansion/contraction and that the embedded uniform micropores enabled a high loading and an efficient trapping of sulfur species during cycling. The LSB coin cell employing the CC-S electrode with an areal sulfur loading of 6 mg/cm2 exhibited a high areal capacity of 4.3 and 3.2 mAh/cm2 at C/10 for 145 cycles and C/3 for 200 cycles, respectively, with minor capacity loss (

Mesoporous melamine resins have been prepared using hexamethoxymethyl melamine (HMMM) as monomer and block-co-polymer Pluronic F127 as template. At acidic conditions, HMMM condenses into melamine resins, replicating the mesophases formed by the block-co-polymer template. The template can be removed by solvent extraction, yielding mesoporous melamine resins with surface areas of up to 258 m2/g and pore diameters of 7.8 nm. At a HMMM/F127 weight ratio of 1:1 an ordered mesoporous melamine resin is observed exhibiting a 2d hexagonal arrangement of cylindrical pores. The simplicity of the synthesis of these mesoporous films allows the large scale production of the materials, for example, in the form of free-standing films.

Carbon and metal nitrides are appealing classes of materials, astheir properties can complement carbon, on the one hand, andmetal oxides, on the other, in a variety of applications. A largernumber of reports in the literature concern the synthesis ofdifferent modifications of carbon nitrides, while at ambientconditions graphitic-C

In this work, the synthesis of porous TiN/carbon composites via “reactive hard templating” is presented. The concept of this synthesis strategy is to use the template, responsible for the final morphology of the TiN/carbon material, as a reactant and nitrogen source; template removal is unnecessary as the final product is obtained as such. As reactive templates, two types of macroporous graphitic carbon nitride powders with different pore sizes (60 nm or 500 nm spherical pores) were used. The powders were infiltrated with a titanium precursor solution, aged for 1 night at 100 °C under air, and subsequently annealed at 800 °C to create the final nanocrystalline porous TiN/carbon structures. The final products were analyzed by XRD, TEM, HRTEM, EA, and gas sorption experiments. It was shown that the morphology of the resulting material generates from a nanocoating of the macropores of the carbon nitride reactive template, yielding aggregated hollow TiN/C spheres with hierarchical porosity.

Serum albumin, one of the most abundant serum proteins, blocks the expression of other important biomarkers. The objective of this study is to remove serum albumin effectively by using solid-phase extraction (SPE) in microfluidic devices. Photo-polymerized adsorbent as a stationary phase of SPE was used to remove bovine serum albumin (BSA). The adsorption capacity was examined with the effect of pH and concentration in BSA solution, and adjustment of monomer concentration such as hydrophilic 2-acrylamido-2-methyl-1-propanesulfonic acid and acrylamide in the adsorbent. The effect of hydrophobic butyl methacylate on BSA adsorption was also studied. Selective removal in a bicomponent with BSA and bovine gamma-globulin was performed by adjusting the pH as required.

In this study, mesoporous silica SBA-15 was functionalized with primary, secondary, and tertiary aminofunctional silanes onto the channel walls using a postsynthesis method as a first attempt to purify succinic acid from a fermentation broth. Ordered mesostructures of pristine and functionalized SBA-15 were evaluated using small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and N2 adsorption/ desorption isotherms. 13 C and 29 Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR) with 1 H cross-polarization (CP-MAS) and thermogravimetric analysis (TGA) revealed that amino-functional silanes were covalently bound to the active layer of pore walls. The distribution and accessibility of amine groups were characterized by scanning transmission electron microscopy (STEM), elemental analysis, and conductivity measurements. Adsorption isotherms were analyzed using the Sips model, simultaneously obtaining the temperature dependence of isotherms derived from the isosteric heats of adsorption. Pyruvic acid had higher adsorption capacities than succinic acid on amine-functionalized SBA-15, resulting in the selective adsorption of pyruvic acid from binary acid solution. In particular, SBA-15 functionalized with primary amino silane obtained higher selectivity on pyruvic acid compared to that of other amine-functionalized SBA-15. The adsorption capacities of pyruvic acid at equilibrium are dependent on the basicity and distribution of amino silanes. The isosteric heats between 10 and 100 kJ/mol and desorption energy between 1 and 10 kJ/mol revealed that the adsorption of pyruvic and succinic acid originated from the formation of an acid-amine complex via hydrogen bonding. It is proposed that the amine functionalization of ordered mesoporous solids provides a simple and effective method of separating or purifying useful carboxylic acids.

Reactive extraction can be used for the recovery of carboxylic acids from fermentation broth. Through the formation of complex with extractants at the two-phase interface, the carboxylic acids are partitioned into organic solvents. However, the recovery of carboxylic acids is interrupted by the conditions of fermentation broth. In this study, the effects of conditions of fermentation broth on the extraction kinetics were investigated using a microporous membrane-based stirred cell for the extraction of succinic acid with tri- n -octylamine. The interfacial concentrations of species in various systems were correlated and thus the effects of pH, salts and contaminated acid on the intrinsic reaction kinetics were discovered. The reaction rate constants were determined from the forward reaction rate equation reported in our previous work. It was found that the extraction rates were steeply decreased at pH values larger than 3 due to the dissociation of carboxylic group. Competitive extraction of salts, which were HPO 4 2− (or PO 4 3− ), CO 3 2− and SO 4 2− , and contaminated acid, which was pyruvic acid, had negative influence on the extraction process of succinic acid and thus the extraction rates were decreased. The interfacial concentrations of succinic acid and TOA in fermentation broth had no difference with those in artificial single acid systems. Therefore, the decrease of extraction rates can be explained by the change of ionic strength in fermentation broth.

Urea is commonly used to lyse cultured cells and solubilize proteins from a biological source. In this study, after extracting biomolecules using a lysis buffer that included urea for an effective cleaning of protein from a urea-rich protein sample, a five-flow microfluidic desalting system was applied using the metal ions of Mn2+, Zn2+ and Fe3+, which have urea affinity-capturing properties. This device effectively removed urea from the sample phase of the microfluidic channel via the diffusion, with a difference of the concentration from the sample flow to both sides of the buffer flow, and an affinity of metal ions into the urea between the buffer phase and the affinity phase. The removal efficiency for the urea was 67, 64, and 63%, with concentrations of 50 mM Mn2+, 10 mM Zn2+, and 5 mM Fe3+ metal ions in the affinity phase, respectively. In addition, protein after desalting with the microfluidic device was improved to more than 10% of the relative activity, with a significant improvement of the signal of mass spectrum shown by MALDI-MS.

A large mesoporous γ-alumina was fabricated through a thermal process without postaddition of molecular or organic solvents at ambient pressure in an open container by using the dual functions of 1-hexadecyl-3-methylimidazolium chloride (C16MimCl) as room-temperature ionic liquids (RTILs), i.e., templating and cosolvent functions. In this synthesis, a thermal process with the assistance of RTILs was the key technology for induction of the nanostructure of aluminum hydroxide and transformation to boehmite crystallites by means of intermolecular interaction. Both C16MimCl/boehmite hybrid and γ-alumina displayed the nanostructure consisting of randomly debundled nanofibers embedded in wormlike porous networks. Nanofibers of C16MimCl/boehmite hybrid and γ-alumina exhibited a length of ca. 40−60 nm and a diameter of ca. 1.5−3 nm. In particular, γ-alumina had good thermal stability and reasonable acidic sites. After conversion from boehmite crystallites into γ-phase by calcination, this nanostructured γ-alumina...

This study was investigated for the enantioselective separation of ( S )-ibuprofen using the ionic liquid in the microfluidic device. A stable and thin ionic liquid flow (ILF) was made by controlling the flow rate of the ILF in the microfluidic channel. In addition, coupling lipase as a biocatalyst with the ILF based on the microfluidic device showed the facilitative and selective transport of ( S )-ibuprofen across the ILF, indicating successful optical resolution of a racemic mixture. Subsequently, the enantioselectivity was evaluated in the transport ratio ( η ) of ( R )- and ( S )-ibuprofen, the optical resolution ratio ( α ) and enantiomeric excess of ( S )-ibuprofen (ee S ).

The present study deals with the development of purification and separation processes required to produce the highly purified succinic acid from the fermentation broth produced by recombinant microorganism, Mannheimia succiniciproducens. The newly developed process consists of the pretreatment process such as reactive extraction and vacuum distillation step and the crystallization process for the highly purified succinic acid production. By-produced acids were effectively removed by the reactive extraction as a primary separation. In addition, the crystallization was applied without adding any salts to produce highly purified succinic acid. The purified succinic acid, with 99.8% purity and 73.1% yield rate was obtained through this newly developed purification process.

The plasma-enhanced chemical vapor (PECVD) co-deposition of pyridine and 1,2 dicarbadodecaborane, 1,2-B10C2H12 (orthocarborane) results in semiconducting boron carbide composite films with a significantly better charge extraction than plasma-enhanced chemical vapor deposited semiconducting boron carbide synthesized from orthocarborane alone. The PECVD pyridine/orthocarborane based semiconducting boron carbide composites, with pyridine/orthocarborane ratios ~3:1 or 9:1 exhibit indirect band gaps of 1.8 eV or 1.6 eV, respectively. These energies are less than the corresponding exciton energies of 2.0 eV–2.1 eV. The capacitance/voltage and current/voltage measurements indicate the hole carrier lifetimes for PECVD pyridine/orthocarborane based semiconducting boron carbide composites (3:1) films of ~350 µs compared to values of ≤35 µs for the PECVD semiconducting boron carbide films fabricated without pyridine. The hole carrier lifetime values are significantly longer than the initial exciton decay times in the region of ~0.05 ns and 0.27 ns for PECVD semiconducting boron carbide films with and without pyridine, respectively, as suggested by the time-resolved photoluminescence. These data indicate enhanced electron–hole separation and charge carrier lifetimes in PECVD pyridine/orthocarborane based semiconducting boron carbide and are consistent with the results of zero bias neutron voltaic measurements indicating significantly enhanced charge collection efficiency.

A turn-on fluorescence sensor, Cu(2+)-c-mpg-C(3)N(4), was developed for detection of CN(-) in aqueous solution by simply mixing cubic mesoporous graphitic carbon nitride (c-mpg-C(3)N(4)) and aqueous solution of Cu(NO(3))(2). The highly sensitive detection of CN(-) with a detection limit of 80 nM is not only possible in aqueous solution but also in human blood serum.

Carbon nitride is an appealing class of material which can complement carbon in a variety of applications. At ambient conditions a graphitic carbon nitride (g-C3N4) is regarded to be the most stable allotrope. Kroke et al. proposed that gC3N4 consists of sheets of ordered tri-s-triazine moieties connected through planar tertiary amino groups stacked in a graphitic fashion. The bulk material synthesis of g-C3N4 was attempted by thermal condensation of nitrogen-rich precursors, even though most reactants do not proceed significantly past the polymeric form owing to incomplete condensation or polymerization in the bulk. A higher condensation degree was achieved by carrying out the condensation in molten salts. Graphitic carbon nitride has recently attracted great interests because of its semiconductor properties, which makes it suitable for photocatalytic applications. The electronic band structure and band gap of g-C3N4 depend on the degree of condensation of the material. It was also proposed that the band gap can be tuned to lower or higher values by protonation or synthesis of inclusion complex with metal cations such as Zn and Fe. g-C3N4 has been used as a photocatalyst for the production of hydrogen and oxygen from water. The introduction of porosity into g-C3N4 yields an increase in the accessible surface area of the material. It was also shown that the catalytic and photocatalytic activity of mpg-C3N4 (“mesoporous graphitic carbon nitride”) greatly improved over that of the bulk material. 10] Optical sensors are molecular receptors whose optical properties change upon binding to specific guests. Optical sensing systems have been intensively investigated for their capability of providing sensitivity and fast and easy detection, biocompatibility, and adaptability to a wide variety of assay conditions. One notable application of optical sensors is in the sensing of metal ions. Especially in industrial areas, large amounts of toxic and carcinogenic metals have been released into the environment, which has strongly raised interest in the biological and environmental monitoring of such compounds. Various optical sensors based on azo-coupled macrocycles, porphyrin, and phenanthroline derivatives have been described for the detection of a wide range of metal ions. The Lewis basic site on these molecular receptors provides strong coordination to metal ions while the net electron transfer from chromophore/fluorophore group in the receptor to the complexed metal ions leads to the qualitative and semiquantitative sensing of metal ions. Recent development in mesoporous materials has improved the performance of these sensors through immobilization of receptors, whereby the receptors are attached to a large and accessible surface area and well-defined pores, favorable for high adsorption capacity of chromogenic/fluorescent molecules and efficient transport of analytes and thus low detection limits of below tens of nanomolar concentrations. There is, however, still growing demand for more advanced optical sensing system with lower detection limit and faster kinetic response. Considering the properties of present chromogenic/fluorescent receptors, it seems that nanostructured g-C3N4 would be a promising alternative. As previously described, the electronic structure of g-C3N4 is adjustable by coupling events of protons or metals to the surface. The surface functionalities of g-C3N4, that is, NH2/ NH /=N , are well-characterized ligands exhibiting high adsorption capacity for metal ions through chelation or redox reaction. Finally, an additional supporting material is not necessary because it is possible to tailor its nanostructure by using any kind of silica hard template. In comparison with the systems in which the receptor is supported on a porous material, and thus constitute just a minor part, considering weight and volume fraction of the overall system, in mpgC3N4 the entire material would be composed of the functional, in this case sensing, material, which principally gives rise to very high sensitivity. Such a nanostructuring is also necessary for efficient transport of metal ions to the surface. Herein, we utilized g-C3N4 as an all-in-one chemosensor to detect trace amounts of metal ions in aqueous solutions. For this purpose 3D cubic (Ia 3d) mesoporous g-C3N4 (c-mpgC3N4) with high surface area was synthesized for the first time. The electronic properties as well as the surface functionalities of c-mpg-C3N4 should make it an efficient optical sensor. Structural characterization of c-mpg-C3N4 was carried out by smalland wide-angle X-ray scattering (SAXS and WAXS), transmission electron microscopy (TEM), N2 sorption, thermogravimetric analysis (TGA), Fourier transform infrared [*] E. Z. Lee, Dr. Y.-S. Jun, Prof. W. H. Hong Department of Chemical and Biomolecular Engineering, KAIST 335 Gwahak-ro, Yuseong-gu, Daejeon, 305-701 (Korea) Fax: (+82)42-350-3910 E-mail: st9750@kaist.ac.kr whhong@kaist.ac.kr Homepage: http://sep.kaist.ac.kr

Kinetic studies for the extraction of succinic acid from aqueous solution with 1-octanol solutions of tri-n-octylamine (TOA) were carried out using a stirred cell with a microporous hydrophobic membrane. The interfacial concentrations of species were correlated and thus the intrinsic kinetics was obtained. The overall extraction process was controlled by the chemical reaction at or near the interface between the aqueous and organic phases. The formation reaction of succinic acid-TOA complex was found to be first order with respect to the concentration of succinic acid in the aqueous phase and the order of 0.5 with respect to that of TOA in the organic phase with a rate constant of (3.14 +/- 0.6) x 10(-8) m(2.5) x mol(-0.5) x s(-1). The dissociation reaction of succinic acid-TOA complex was found to be the second-order with respect to that of succinic acid-TOA complex in the organic phase and the order of -2 with respect to that of TOA in the organic phase with a rate constant of (1.44 +/- 1.4) x 10(-4) mol x m(-2) x s(-1).