Analysis of problematic complexing behavior of ferric chloride with N,N-dimethylformamide using combined techniques of FT-IR, XPS, and TGA/DTG

Constructing novel hydrated metal molten salt with high self-healing as the anode material for lithium-ion batteries

Lithium-ion batteries (LIBs) are greatly limited in their practical application because of their poor cycle performance, low conductivity and volume expansion. Herein, molten salts (MSs) FeCl3·6H2O-NMP with low temperature via simple preparation are used as the anode material of LIBs for the first time to break through the bottleneck of LIBs. The good fluidity and high self-healing of FeCl3·6H2O-NMP effectively avoid the collapse and breakage of the structure. Based on this feature, the initial discharge specific capacity reached 770.28 mA h g-1, which was more than twice that of the commercial graphite anode. After 200 cycles at a current density of 100 mA g-1, the specific capacity did not decrease rather it was found to be higher than the initial discharge specific capacity, reaching 867.24 mA h g-1. Besides, the good conductivity of MSs provides convenience for the removal and intercalation of Li+. The active H sites that can combine with lithium ions form LiH and provide capacity for LIBs. Density functional theory (DFT) calculation also provided theoretical proof for the mechanism of LIBs.

Sodium alginate reinforced polyacrylamide/xanthan gum double network ionic hydrogels for stress sensing and self-powered wearable device applications

Strong and ductile sodium alginate (SA) reinforced polyacrylamide (PAM)/xanthan gum (XG) double network ionic hydrogels were constructed for stress sensing and self-powered wearable device applications. In the designed network of PXS-Mⁿ⁺/LiCl (short for PAM/XG/SA-Mⁿ⁺/LiCl, where Mⁿ⁺ stands for Fe³⁺, Cu²⁺ or Zn²⁺), PAM acts as a flexible hydrophilic skeleton, and XG functions as a ductile second network. The macromolecule SA interacts with metal ion Mⁿ⁺ to form a unique complex structure, significantly improving the mechanical strength of the hydrogel. The addition of inorganic salt LiCl endows the hydrogel with high electrical conductivity, and meanwhile reduces the freezing point and prevents water loss of the hydrogel. PXS-Mⁿ⁺/LiCl exhibits excellent mechanical properties and ultra-high ductility (a fracture tensile strength up to 0.65 MPa and a fracture strain up to 1800%), and high stress-sensing performance (a high GF up to 4.56 and pressure sensitivity of 0.122). Moreover, a self-powered device with a dual-power-supply mode, i.e., PXS-Mⁿ⁺/LiCl-based primary battery and TENG, and a capacitor as the energy storage component was constructed, which shows promising prospects for self-powered wearable electronics.

Electrochemical Investigation of Iron-Catalyzed Atom Transfer Radical Polymerization

Use of iron-based catalysts in atom transfer radical polymerization (ATRP) is very interesting because of the abundance of the metal and its biocompatibility. Although the mechanism of action is not well understood yet, iron halide salts are usually used as catalysts, often in the presence of nitrogen or phosphorous ligands (L). In this study, electrochemically mediated ATRP (eATRP) of methyl methacrylate (MMA) catalyzed by FeCl3, both in the absence and presence of additional ligands, was investigated in dimethylformamide. The electrochemical behavior of FeCl3 and FeCl3/L was deeply investigated showing the speciation of Fe(III) and Fe(II) and the role played by added ligands. It is shown that amine ligands form stable iron complexes, whereas phosphines act as reducing agents. eATRP of MMA catalyzed by FeCl3 was investigated in different conditions. In particular, the effects of temperature, catalyst concentration, catalyst-to-initiator ratio, halide ion excess and added ligands were investigated. In general, polymerization was moderately fast but difficult to control. Surprisingly, the best results were obtained with FeCl3 without any other ligand. Electrogenerated Fe(II) effectively activates the dormant chains but deactivation of the propagating radicals by Fe(III) species is less efficient, resulting in dispersity > 1.5, unless a high concentration of FeCl3 is used.

The Effect of Chlorine Modification of Precipitated Iron Catalysts on Their Fischer–Tropsch Synthesis Properties

Precipitated iron Fischer–Tropsch synthesis catalysts impregnated with chlorine were prepared and their Fischer–Tropsch synthesis performances were tested in a 1 L stirred tank reactor. The results showed that the chlorine modification had a significant influence on the Fischer–Tropsch synthesis performance of the precipitated iron catalyst. Compared with the catalyst without the chlorine modification, the catalyst containing about 0.1 wt% chlorine was deactivated by about 40% and the catalyst containing about 1 wt% chlorine was deactivated by about 65%. The textural properties, phase, reduction properties, and chlorine adsorption state of the catalysts before and after the Fischer–Tropsch synthesis were characterized. The strong interaction between chlorine and iron in the catalyst hindered the reduction and carbonization of the catalyst, which was the reason for the deactivation of the catalyst caused by the chlorine modification.

Synthesis of Layered Double Hydroxides with Phosphate Tailings and Its Effect on Flame Retardancy of Epoxy Resin

In this work, phosphate tailings (PTs) were used as raw materials for the preparation of Ca-Mg-Al layered double hydroxides (LDHs-1) and Ca-Mg-Al-Fe layered double hydroxides (LDHs-2) by co-precipitation method. The as-prepared samples were characterized by FT-IR, SEM, XRD, and XPS and applied as a flame retardant to improve the fire safety of epoxy resin (EP). The results showed that both LDHs-1 and LDHs-2 exhibited layered structure and high crystallinity. Compared with neat EP, the value of limiting oxygen index (LOI) increased from 25.8 to 29.3 and 29.9 with 8 wt% content of LDHs-1 and LDHs-2, respectively. The flame retardant properties of the composite material were characterized by cone calorimeter (CC), and the results showed that the peak value of the smoke production rate (SPR) decreased more than 45% and 74%, total smoke production (TSP) reduced nearly 64% and 85% with the addition of LDHs-1 and LDHs-2. Meanwhile, the value of the total heat release (THR) reduced more than 28% and 63%. The conversion from LDHs to layered double oxide (LDO) might be conducive to the fire safety of EP. Moreover, the transformation of Fe-OH to Fe-O could promote the early cross-linking of polymer. In summary, LDHs-2 could significantly improve the carbonization process of EP and suppress the smoke released during the combustion process.

Preparation of a Novel Organic Phosphonic Acid Intercalated Phosphate Tailings Based Hydrotalcite and Its Application in Enhancing Fire Safety for Epoxy Resin

Phosphate tailings (PTs) are solid waste, which is produced by phosphate flotation. In this work, PTs were used as raw materials for the preparation of diethylenetriamine pentamethronic acid (DTPMP) intercalated trimetal (Ca-Mg-Al) layered double hydroxides (TM-DTPMP LDHs) by co-precipitation method. TM-DTPMP LDHs were characterized by X-ray diffraction, fourier-transform infrared spectroscopy, scanning electron microscopy, differential thermal gravimetric analysis, X-ray photoelectron spectroscopy and applied as a flame retardant to improve the fire safety of epoxy resin (EP). The results showed that the composite materials exhibited obvious layered structure. After intercalation, layer spacing increased from 0.783 to 1.78 Å. When the amount of TM-DTPMP LDH in EP was 8%, the limitted oxygen index of the composite material increased from the original 19.2% to 30.2%. In addition, Cone calorimeter (CC) and Raman spectrum results indicated that with the addition of TM-DTPMP LDHs, the value of heat release rate peak (pHRR) and total heat release (THR) were reduced by more than 43% and 60%, while the value of smoke formation rate (pSPR) and the total smoke production (TSP) decreased nearly 64% and 83%, respectively. The significant reduction in the release of combustion heat and harmful smoke during EP combustion may be attributed to the synergistic flame-retardant effect between hydrotalcite and DTPMP. This work exhibited great potential for the green recycling of PTs and the enhancement of the fire safety of EP.

Facile One-Pot Synthesis of Zn/Mg-MOF-74 with Unsaturated Coordination Metal Centers for Efficient CO2 Adsorption and Conversion to Cyclic Carbonates

Bimetallic metal-organic frameworks (MOFs) containing two different inorganic metal nodes exhibited enhanced properties in CO₂ adsorption and catalytic conversion compared with the corresponding monometallic MOFs. In this work, the novel bimetallic Zn/Mg-MOF-74 with different ratios of Zn/Mg was synthesized successfully by a facile one-pot method. Powder X-ray diffraction, Fourier transform infrared, X-ray photoelectron spectroscopy, scanning electron microscopy/transmission electron microscopy, N₂/CO₂ adsorption/desorption, and CO₂/NH₃-temperature-programmed desorption techniques thoroughly characterized the structure, morphology, and physicochemical properties of Zn/Mg-MOF-74. Besides the excellent CO₂ adsorption capacity (128.3 cm³/g at 273 K and 1 bar), Zn_0.75Mg_0.25-MOF-74 also showed efficient catalytic activity for the cycloaddition reaction of CO₂ and epoxides to cyclic carbonates with outstanding yield and selectivity all over 99% under solvent-free and mild conditions (60 °C, 0.8 MPa), outperforming the mechanical combination of Zn-MOF-74 and Mg-MOF-74 with the same metal contents, indicating the synergistic effect of two adjacent metals in bimetallic MOF-74. In addition, the Zn_0.75Mg_0.25-MOF-74 catalyst could be recycled for at least five runs and possess good versatility to various substrates. Finally, a feasible mechanism of the catalytic reaction was proposed. Thanks to the high surface area, affinity toward CO₂, and accessibility of multiple active sites of the unsaturated metal centers as active Lewis acid sites and O atoms from Zn-O and Mg-O as Lewis basic sites, efficient chemical fixation of CO₂ to cyclic carbonates was obtained over the Zn_0.75Mg_0.25-MOF-74 catalyst. The present facile synthesis and application of a robust bimetallic MOF catalyst offered a competitive avenue for the integration of CO₂ adsorption and CO₂ catalytic conversion.

Chitin as a Sorbent Superior to Other Biopolymers: Features and Applications in Environmental Research, Energy Conversion, and Understanding Evolution of Animals

Chitin is an effective sorbent which can be used in environmental monitoring, beyond obvious applications in withholding metal-containing pollutants from wastewater- or nuclear fuel reprocessing flows, since background levels in (purified) chitin are very low except for a few metals (Fe, Cu, Al, Ti, and Zn). Since retention of Mx+ and their complexes on chitin depend on an oxidation state, and to a lesser extent the presence of possible ligands or co-ligands, partition between chitin samples exposed to sediment and those exposed to water can be changed by environmental factors such as local biota producing or absorbing/metabolizing effective ligands such as citrate or oxalate and by changes of redox potential. Thermodynamics are studied via log P, using calibration functions log P vs. 1/r or log P vs. Σσ (sum of Hammett parameters of ligand donor groups) for di- and trivalent elements not involved in biochemical activity (not even indirectly) and thus measuring “deviations” from expected values. These “deviations” can be due to input as a pollutant, biochemical use of certain elements, precipitation or (bio-induced reduction of SO42− or CO2) dissolution of solids in sediment. Biochemical processes which occur deep in sediment can be detected due to this effect. Data from grafted chitin (saturation within ≤ 10 min) and from outer surfaces of arthropods caught at the same site do agree well. Log P is more telling than total amounts retrieved. Future applications of these features of chitin are outlined.

Microtubular PEDOT-Coated Bricks for Atmospheric Water Harvesting

Atmospheric water harvesting is a promising technology for alleviating global water scarcity. Current water sorption materials efficiently capture water vapor from ubiquitous air; however, they are difficult to scale up due to high costs, complex device engineering, and intensive energy consumption. Fired red brick, a low-cost masonry construction material, holds the potential for developing large-scale functional architectures. Here, we utilize fired red brick for atmospheric water harvesting by integrating a microtubular coating of the conducting polymer PEDOT within its inorganic microstructure. This microtubular polymer coating affords hygroscopicity and high surface area for water nucleation, enables capillary forces to promote water transport, and enhances the water harvesting efficiency. Our brick composite achieves a maximum water vapor uptake of ∼200 wt % versus polymer mass at 95% relative humidity, decreasing to ∼15 wt % at 40% relative humidity. Facile water release is demonstrated via thermal, electrical, and illuminative heating. This proof-of-concept study demonstrates the potential of masonry construction materials for large-scale atmospheric water harvesting.

Emerging Pyroelectric Nanogenerators to Convert Thermal Energy into Electrical Energy

Pyroelectric energy harvesting systems have recently received substantial attention for their potential applications as power generators. In particular, the pyroelectric effect, which converts thermal energy into electrical energy, has been utilized as an infrared (IR) sensor, but upcoming sensor technology that requires a miniscule amount of power is able to utilize pyroelectric nanogenerators (PyNGs) as a power source. Herein, an overview of the progress in the development of PyNGs for an energy harvesting system that uses environmental or artificial energies such as the sun, body heat, and heaters, is provided. It begins with a brief introduction of the pyroelectric effect, and various polymer and ceramic materials based PyNGs are reviewed in detail. Various approaches for developing polymer-based PyNGs and various ceramic materials-based PyNGs are summarized in particular. Finally, challenges and perspectives regarding the PyNGs are described.

Biological synthesis of iron nanoparticles using hydrolysates from a waste-based biorefinery

The purpose of this work was to produce iron nanoparticles (Fe-NP) by microbial pathway from anaerobic bacteria grown in anaerobic fluidized bed reactors (AnFBRs) that constitute a new stage of a waste-based biorefinery. Bioparticles from biological fluidized bed reactors from a biorefinery of organic fraction of municipal solid wastes (that produces hydrolysates rich in reducing sugars) were nanodecorated (embedded nanobioparticle or nanodecorated bioparticle, ENBP) by biological reduction of iron salts. Factors "origin of bioparticles" (either from hydrogenogenic or methanogenic fluidized bed reactor) and "type of iron precursor salt" (iron chloride or iron citrate) were explored. SEM and high-resolution transmission electron microscopy (HRTEM) showed amorphous distribution of nanoparticles (NP) on the bioparticles surface, although small structures that are nanoparticle-like could be seen in the SEM micrographs. Some agglomeration of NPs was confirmed by DLS. Average NP size was lower in general for NP in ENBP-M than ENBP-H according to HRTEM. The factors did not have a significant influence on the specific surface area of NPs, which was high and in the range 490 to 650 m² g^-1. Analysis by EDS displayed consistent iron concentration 60-65% iron in nanoparticles present in ENBP-M (bioparticles previously grown in methanogenic bioreactor), whereas the iron concentration in NPs present in ENBP-H (bioparticles previously grown in hydrogenogenic bioreactor) was more variable in a range from 8.5 to 62%, depending on the iron salt. X-ray diffraction patterns showed the typical peaks for magnetite at 35° (3 1 1), 43° (4 0 0), and 62° (4 0 0); moreover, siderite diffraction pattern was found at 26° (0 1 2), 38° (1 1 0), and 42° (1 1 3). Results of infrared analysis of ENBP in our work were congruent with presence of magnetite and occasionally siderite determined by XRD analysis as well as presence of both Fe⁺² and F⁺³ (and selected satellite signal peaks) observed by XPS. Our results on the ENBPs hold promise for water treatment, since iron NPs are commonly used in wastewater technologies that treat a wide variety of pollutants. Finally, the biological production of ENBP coupled to a biorefinery could become an environmentally friendly platform for nanomaterial biosynthesis as well as an additional source of revenues for a waste-based biorefinery.

A Solution-based Method for Synthesizing Pyrite-type Ferrous Metal Sulfide Microspheres with Efficient OER Activity

Simple and stable synthesis of transition metal sulfides and clarification of their growth mechanisms are of great importance for developing catalysts, metal-air batteries and other technologies. In this work, we developed a one-step facile hydrothermal approach to successfully synthesize NiS₂ microspheres. By changing the experimental parameters, the reason that affects the formation of nanostructured spheres is investigated and discussed in detail, and the formation mechanism of microspheres is proposed innovatively. Furthermore, electrochemical testing results show that the 7 h-NiS₂ catalyst exhibits a remarkable oxygen evolution reaction (OER) activity with an overpotential of 311 mV at 10 mA cm^-2 in 1.0 M KOH, superior to precious metal RuO₂ . The NiS₂ catalyst also exhibits a robust durability. This work will contributes to the rational design and the understanding of growth mechanism of transition metal chalcogenide electrocatalysts for diverse energy conversion technologies.

Synthesis of N-(3-aminopropyl)imidazole-based poly(ionic liquid) as an adsorbent for the selective recovery of Au(iii) ions from aqueous solutions

A novel poly(ionic liquid) adsorbent (PIL-APIBCl) exhibits a high adsorption capacity of 236.68 mg g⁻¹ for Au(iii).

Ru nanoclusters confined in porous organic cages for catalytic hydrolysis of ammonia borane and tandem hydrogenation reaction

The fabrication of narrow-sized metal nanoclusters for heterogeneous catalysis has attracted widespread research attention. Nevertheless, it is still a significant challenge to fabricate highly dispersed metal-nanocluster-based catalysts with high activity and stability. In this study, 1,3,5-benzenetricarboxylate and 1,2-diaminocyclohexane were used as precursors to fabricate porous organic cages (POCs), CC3-R. CC3-R exhibited a high specific surface area and a microporous-mesoporous structure. In addition, ultrafine Ru nanoclusters were successfully encapsulated in CC3-R with high dispersion via impregnation and subsequent reduction, affording Ru nanoclusters with a precisely controlled size of ∼0.65 nm. As-obtained Ru(1.45%)@CC3-R exhibited significantly enhanced catalytic activities toward the hydrolysis of ammonia borane (AB) and exhibited high conversion and selectivity for the tandem hydrogenation of nitroarenes and hydrogenation of quinoline in water under mild conditions. In addition, the Ru(1.45%)@CC3-R catalyst exhibited high stability and good recyclability. This study should provide a novel strategy for fabricating highly dispersed ultrafine nanocluster-based catalysts for various catalysis applications.

Modification of CuCl2·2H2O by dielectric barrier discharge and its application in the hydroxylation of benzene

A DBD plasma converts a homogeneous catalyst CuCl₂·H₂O into a heterogeneous catalyst CuCl₂–DBD by removing some chlorine from CuCl₂·H₂O.

A hybrid strain and thermal energy harvester based on an infra-red sensitive Er3+ modified poly(vinylidene fluoride) ferroelectret structure

In this paper, a novel infra-red (IR) sensitive Er3+ modified poly(vinylidene fluoride) (PVDF) (Er-PVDF) film is developed for converting both mechanical and thermal energies into useful electrical power. The addition of Er3+ to PVDF is shown to improve piezoelectric properties due to the formation of a self-polarized ferroelectric β-phase and the creation of an electret-like porous structure. In addition, we demonstrate that Er3+ acts to enhance heat transfer into the Er-PVDF film due to its excellent infrared absorbance, which, leads to rapid and large temperature fluctuations and improved pyroelectric energy transformation. We demonstrate the potential of this novel material for mechanical energy harvesting by creating a durable ferroelectret energy harvester/nanogenerator (FTNG). The high thermal stability of the β-phase enables the FTNG to harvest large temperature fluctuations (ΔT ~ 24 K). Moreover, the superior mechanosensitivity, SM ~ 3.4 VPa-1 of the FTNG enables the design of a wearable self-powered health-care monitoring system by human-machine integration. The combination of rare-earth ion, Er3+ with the ferroelectricity of PVDF provides a new and robust approach for delivering smart materials and structures for self-powered wireless technologies, sensors and Internet of Things (IoT) devices.

Facile Approach to Preparing a Vanadium Oxide Hydrate Layer as a Hole-Transport Layer for High-Performance Polymer Solar Cells

We demonstrate a facile and green approach to preparing a vanadium oxide hydrate (VO_x·nH₂O) layer to serve as the hole-transport layer (HTL) in high-performance polymer solar cells (PSCs). The VO_x·nH₂O layer was in situ prepared by a combined H₂O₂ and ultraviolet-ozone (UVO) processing on a VO_x layer. The as-prepared VO_x·nH₂O layer featured a work function of 5.0 ± 0.1 eV, high transmittance, and better interface properties compared to those of the generally prepared VO_x (UVO or thermal annealing) layers. PSCs based on poly[(ethylhexyl-thiophenyl)-benzodithiophene-(ethylhexyl)-thienothiophene]/[6,6]-phenyl-C₇₁-butyric acid methyl ester using the VO_x·nH₂O layer as the HTL yielded high power conversion efficiencies (PCEs) up to 8.11%, outperforming the devices with VO_x layers (PCE of 6.79% for the UVO-processed VO_x layer and 6.10% for the thermally annealed VO_x layer) and conventional polyethylenedioxythiophene-polystyrenesulfonate (PEDOT:PSS) layers (PCE of 7.67%). The improved PCE was attributed to the enhanced J_SC and/or fill factor, which mainly correlate to the improved interfacial contact between the photoactive layer and the indium tin oxide/HTL or cathode when using the VO_x·nH₂O layer as the HTL. A similar improvement in the PCE was also observed for the PSCs based on poly(3-hexylthiophene)/[6,6]-phenyl-C₆₁-butyric acid methyl ester. In addition, PSCs with a VO_x·nH₂O layer as the HTL showed a higher stability than that of those with a PEDOT:PSS layer. Hence, it would be possible to use this simply and in situ prepared VO_x·nH₂O layer as an inexpensive HTL for high-performance PSCs.

Enhanced electro-active phase in a luminescent P(VDF–HFP)/Zn2+ flexible composite film for piezoelectric based energy harvesting applications and self-powered UV light detection

An electro-active P(VDF–HFP)/Zn²⁺ composite film scavenges the mechanical energy that enabled self-powered UV light detection.

Hybrid Perovskite Thin-Film Photovoltaics: In Situ Diagnostics and Importance of the Precursor Solvate Phases

Solution-processed hybrid perovskite semiconductors attract a great deal of attention, but little is known about their formation process. The one-step spin-coating process of perovskites is investigated in situ, revealing that thin-film formation is mediated by solid-state precursor solvates and their nature. The stability of these intermediate phases directly impacts the quality and reproducibility of thermally converted perovskite films and their photovoltaic performance.

Enabling Design of Advanced Elastomer with Bioinspired Metal-Oxygen Coordination

It poses a huge challenge to expand the application gallery of rubbers into advanced smart materials and achieve the reinforcement simultaneously. In the present work, inspired by the metal-ligand complexations of mussel byssus, ferric ion was introduced into an oxygen-abundant rubber network to create additional metal-oxygen coordination cross-links. Such complexation has been revealed to be highly efficient in enhancing the strength and toughness of the rubbers. Significantly, such complexation also enables the functionalization of the rubber into highly damping or excellent multishape memory materials. We envision that the present work offers an efficient yet facile way of creating advanced elastomers based on industrially available diene-based rubber.

Cellulose nanofiber backboned Prussian blue nanoparticles as powerful adsorbents for the selective elimination of radioactive cesium

On 11 March 2011, the day of the unforgettable disaster of the 9 magnitude Tohoku earthquake and quickly followed by the devastating Tsunami, a damageable amount of radionuclides had dispersed from the Fukushima Daiichi's damaged nuclear reactors. Decontamination of the dispersed radionuclides from seawater and soil, due to the huge amounts of coexisting ions with competitive functionalities, has been the topmost difficulty. Ferric hexacyanoferrate, also known as Prussian blue (PB), has been the most powerful material for selectively trapping the radioactive cesium ions; its high tendency to form stable colloids in water, however, has made PB to be impossible for the open-field radioactive cesium decontamination applications. A nano/nano combinatorial approach, as is described in this study, has provided an ultimate solution to this intrinsic colloid formation difficulty of PB. Cellulose nanofibers (CNF) were used to immobilize PB via the creation of CNF-backboned PB. The CNF-backboned PB (CNF/PB) was found to be highly tolerant to water and moreover, it gave a 139 mg/g capability and a million (10⁶) order of magnitude distribution coefficient (K_d) for absorbing of the radioactive cesium ion. Field studies on soil and seawater decontaminations in Fukushima gave satisfactory results, demonstrating high capabilities of CNF/PB for practical applications.

The influence of hydrogen bonding on the dielectric constant and the piezoelectric energy harvesting performance of hydrated metal salt mediated PVDF films

Polyvinylidene fluoride (PVDF) films are filled with various mass fractions (wt%) of hydrated metal salt (MgCl2·6H2O) (Mg-salt) to fabricate high performance piezoelectric energy harvesters (PEHs). They deliver up to 4 V of open circuit voltage by simply repeated human finger imparting (under a pressure of ∼4.45 kPa) and also generate sufficient power to turn on at least ten commercial blue light emitting diodes (LEDs) instantly. The enhanced piezo-response is attributed to the combined effect of the change in the inherent dipole moment of the electroactive phase containing PVDF itself and H-bonding arising between the Mg-salt filler and PVDF via electrostatic interactions. Furthermore, it also successfully charged the capacitors, signifying practical applicability as a piezoelectric based energy harvester power source. UV-visible optical absorption spectral analysis revealed the possibility to estimate a change in the optical band gap value at different concentrations of Mg-salt filler added PVDF films that possess a useful methodology where the Mg-salt can be used as an optical probe. In addition dielectric properties have been studied to understand the role of molecular kinetic and interfacial polarization occurs in H-bond PVDF films at different applied frequencies at room temperature.

High nitrogen-doped carbon/Mn3O4 hybrids synthesized from nitrogen-rich coordination polymer particles as supercapacitor electrodes

High nitrogen-doped carbon/Mn3O4 composites were synthesized by annealing nitrogen-rich Mn-based coordination polymer particles, and investigated by electron microscopy, X-ray diffraction, and electrochemical experiments. To assess the performance of high nitrogen-doped hybrids as electrode materials in supercapacitors, cyclic voltammetry and galvanostatic charging-discharging measurements are performed. High nitrogen-doped carbon/Mn3O4 composites are charged and discharged faster and have higher capacitance than carbon/Mn3O4 nanostructures with low nitrogen amounts and other reported ones. The capacitance of the high nitrogen-doped carbon/Mn3O4 is 94% retained after 1000 cycles at a constant current. These improvements can be attributed to the nitrogen-doped carbon matrix, which promotes fast Faradaic charging and discharging of the Mn3O4 motifs. The nitrogen-doped carbon/Mn3O4 composites could be a promising candidate material for a high-capacity, low-cost, and environmentally friendly electrode for supercapacitors.

Iron-catalyzed atom transfer radical polymerization

This article reviews the preparation of polymers using iron-catalyzed atom transfer radical polymerization.

Preparation of graphene oxide-silver nanoparticle nanohybrids with highly antibacterial capability

A simple method based on electrostatic interactions was utilized to assemble silver nanoparticles (AgNPs) to graphene oxide (GO) sheets. This method allows conjugation of AgNPs with desired morphologies (densities, sizes and shapes) onto GO. In this process, poly(diallyldimethylammonium chloride) (PDDA) was introduced as an adhesive agent. The as-prepared graphene oxide-AgNPs composites (GO-AgNPs) have enhanced colloid stability and photo-stability than that of AgNPs. After conjugating to GO sheets, the antibacterial activities of AgNPs against Gram negative (G-) bacterial strain (Escherichia coli, E. coli) and Gram positive (G+) bacterial strain (Bacillus subtilis, B. subtilis) have been improved significantly. The antibacterial activity of GO-AgNPs is dependent on the size of AgNPs, i.e. the small AgNPs modified GO sheets show more effective antibacterial capability than that of large AgNPs modified GO sheets. Compared with AgNPs, the enhanced antibacterial activity of GO-AgNPs might not only be due to high stability of AgNPs anchored on GO sheets, but also the positive charged surface of hybrids which increases the electrostatic interaction of bacterial cell membrane with nanohybrids.