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Herein, catalytically active cyclodextrin (CD) nanofibers loaded with in situ formed Pd nanoparticles (Pd-NPs) were prepared by solution electrospinning. Cyclodextrin (CD) acted as a reducing agent and catalyzed the formation of noble metal nanoparticles, e.g., palladium (Pd) over the reduction from Pd2+ to metallic Pd0, without requiring any other reducing agent. Nanofibers were produced by the electrospinning of CD molecules from aqueous and DMF solutions containing two different Pd loadings (1 and 2 wt% with respect to CD). The electrospinning of these solutions could give rise to bead-free CD nanofibers whose diameters showed variations depending on the solvent-type and the Pd content used: the nanofibers electrospun from DMF solutions were smaller in diameter than those produced from aqueous solutions. Furthermore, increasing Pd loading decreased the nanofiber diameter. TEM, HRTEM, STEM and SAED analyses confirmed the presence of homogeneously distributed polycrystalline Pd-NPs in the size range of 3–5 nm throughout the nanofiber matrix. XPS experiments demonstrated the presence of a higher proportion of metallic Pd0 atoms owing to the efficient reduction of Pd2+ by CD molecules. Lastly, the catalytic activity of the nanocomposite nanofibers was explored by the reduction of a nitroarene compound, p-nitrophenol (PNP), to p-aminophenol (PAP), and high catalytic activity of the nanofibers was observed. [ABSTRACT FROM AUTHOR]

The developments in environmental remediation based on the advanced oxidation processes of catalyst surfaces still endure the burden of the effective recombination of photoinduced charge carriers. The construction of defect band levels with heterostructural phases of catalytic nanostructures is a tenable strategy for separating photogenerated charge carriers and for minimizing carrier recombination. Herein, we explain an effective carrier separation rate with extended light absorption using electrospun ZnTi-based semiconducting nanofibers, which feature as composites and ternary form for their structural geometry. We explain the effective surface functionality with the design of the ZnO-TiO2 composite and ZnTiO3 as a function of the annealing temperature on electrospun fibers, and their commendable visible catalytic properties with the presence of defect states for degrading organic pollutants. The constructed ZnTiO3 in the form of nanofibers induced a narrow band gap of 3.01 eV as compared with its individual counterparts (ZnO (3.27 eV) and TiO2 (3.17 eV)). However, the composite functionality has an advantage in inducing discrete defect levels with the carbon impurities for favorable extended visible absorption with a similar morphological nature. Under visible irradiation, the ternary form of the nanofibers exhibited a photocatalytic degradation performance of around 72.45% and the composite fibers exhibited one of around 95.82% in 125 min due to the scrutinized function of the defect states that maximize the interfacial charge transfer between ZnO-C-TiO2 and delay the carrier recombination rate. The reliable mechanism behind the charge transfer of the photogenerated carriers was supported by trapping experiments of two different geometrical nanostructures on degrading organic pollutants. The interesting results obtained from the stability and reusability studies were that the ZnO-TiO2 composite nanofibers have a notably surface photocorrosive nature after catalytic reaction but the ternary ZnTiO3 form of the nanofibers has a stable surface stability with stable reusable catalytic functionality for up to 20 consecutive cycles. Constructing the nanostructures with tunable surface structural natures anticipates the broad possibilities in the photocatalytic realm for achieving improved visible catalytic responses with stable and reusable functionality over their single counterparts. [ABSTRACT FROM AUTHOR]

We have juxtaposed the structural, vibrational and emission properties of graphene oxide (GO) with various degrees of reduction with and without a model dispersant, unveiling a strong associative behavior between GO sheets and the influence of H-bonds. The interlayer spacings are ∼0.84 and 0.78 nm for the as prepared and reduced samples. –OH groups are predominantly effected by the photo-thermal reduction. Also we note some regeneration of ⧸⧹C=O and –COOH groups in reduced samples. Clear changes to the phonon density of states indicated the doping effects due to H-bonds via the oxygeneous groups. Importantly, the defect related Raman bands are rather prone to the effect of dispersant, unveiling their intrinsic nature. In the context of fluorescence, internal vibration relaxation mediated by CC stretch vibrations emphasized the localized nature of sp2 domains of relatively smaller size. Fluorescence consists of 6 components, where the higher energy components are more influenced due to H-bonds than those of the lower energy regime, attributed to their associative behavior and chemical functionality, respectively. Excitation dependent fluorescence measurements indicated a range of optical gaps from ∼3.5 to 2 eV. The associative behavior of GO and rGO with and without a dispersant provides crucial insights into the fundamental understanding of various molecular processes. [ABSTRACT FROM AUTHOR]

Surface-modified TiO2 nanofibers (NFs) with tunable visible-light photoactive catalysts were synthesised through electrospinning, followed by a sulfidation process. The utilization of sodium-based sulfidation precursors effectively led to the diffusion and integration of sulfur impurities into TiO2, modifying its band function. The optical band function of the sulfur-modified TiO2 NFs can be easily manipulated from 3.17 eV to 2.28 eV through surface modification, due to the creation of oxygen vacancies through the sulfidation process. Sulfidating TiO2 NFs introduces Ti–S-based nanograins and oxygen vacancies on the surface that favor the TiO2–TiS3 core–shell interface. These defect states extend the photocatalytic activity of the TiO2 NFs under visible irradiation and improve effective carrier separation and the production of reactive oxygen species. The surface oxygen vacancies and the Ti–S-based surface nanograins serve as charge traps and act as adsorption sites, improving the carrier mobility and avoiding charge recombination. The diffused S-modified TiO2 NFs exhibit a degradation rate of 0.0365 cm−1 for RhB dye solution, which is 4.8 times higher than that of pristine TiO2 NFs under visible irradiation. By benefiting from the sulfur states and oxygen vacancies, with a narrowed band gap of 2.3 eV, these nanofibers serve as suitable localized states for effective carrier separation. [ABSTRACT FROM AUTHOR]

Plasmonic enhancement for electron–hole separation efficiency and visible light photocatalysis was achieved by Pd nanocube decoration on a ZnO nanolayer coated onto electrospun polymeric (polyacrylonitrile (PAN)) nanofibers. Since exciton formation and sustainable electron–hole separation have a vital importance for realizing better solar energy in photovoltaic and photocatalytic devices, we achieved visible light photocatalysis by Pd nanocube decoration onto well designed core–shell nanofibers of ZnO@PAN-NF. By controlling the cubic Pd nanoparticle size and the thickness of the crystalline ZnO nanolayer deposited onto electrospun PAN nanofibers via atomic layer deposition (ALD), defect mediated visible light photocatalysis efficiency can be increased. By utilizing nanofabrication techniques such as thermal decomposition, electrospinning and ALD, this fabricated template became an efficient, defect mediated, Pd nanocube plasmon enhanced photocatalytic system. Due to the enhanced contact features of the Pd nanocubes, an increase was observed for the visible light photocatalytic activity of the flexible and nanofibrous mat of Pd@ZnO@PAN-NF. [ABSTRACT FROM AUTHOR]

UV range light was used for the facile, effective and large-scale synthesis of visible light emitting, surface-protected silicon quantum dots (Si QDs) starting from an amine-functionalized alkoxy silane precursor. Within mild and easy hydrolysis/condensation environments, the use of an amine-functionalized precursor together with a reducing agent resulted in a bright visible green light that could be used for fluorescent analytical detection systems. Visible light emitting Si QDs were investigated and it was found that their emission character depends on the illumination time, hydrolysis/condensation conditions and pretreatments for the silane coupling agents. A Nylon 6,6 electrospun nanofibrous mat was selected as a substrate for decoration by the Si QDs in order to fabricate a flexible and free-standing polymeric nanofibrous mat posessing a visible light emitting character so that it could act as a visible colorimetric sensor. The visible light emitting Si QDs were decorated onto the Nylon 6,6 nanofibrous mats via covering the surfaces as a ‘nanodress’ by a simple impregnation/dip-coating and heat-curing methods. The analytical results revealed that the Si QDs decorated flexible polymeric nanofibrous mats could be utilized for colorimetric trinitrotoluene (TNT) detection in low concentrations. [ABSTRACT FROM AUTHOR]

Guidance of neurite extension and establishment of neural connectivity hold great importance for neural tissue regeneration and neural conduit implants. Although bioactive-epitope functionalized synthetic or natural polymeric materials have been proposed for the induction of neural regeneration, chemical modifications of these materials for neural differentiation still remain a challenge due to the harsh conditions of chemical reactions, along with non-homogeneous surface modifications. In this study, a facile noncovalent functionalization method is proposed by exploiting host–guest interactions between an adamantane-conjugated laminin derived bioactive IKVAV epitope and electrospun cyclodextrin nanofibers (CDNFs) to fabricate implantable scaffolds for peripheral nerve regeneration. While electrospun CDNFs introduce a three-dimensional biocompatible microenvironment to promote cellular viability and adhesion, the bioactive epitopes presented on the surface of electrospun CDNFs guide the cellular differentiation of PC-12 cells. In addition to materials synthesis and smart functionalization, physical alignment of the electrospun nanofibers guides the cells for enhanced differentiation. Cells cultured on aligned and IKVAV functionalized electrospun CDNFs had significantly higher expression of neuron-specific βIII-tubulin and synaptophysin. The neurite extension is also higher on the bioactive aligned scaffolds compared to random and non-functionalized electrospun CDNFs. Both chemical and physical cues were utilized for an effective neuronal differentiation process. [ABSTRACT FROM AUTHOR]

Electrospun ZnO nanofibers (ZNF) have received increased attention as photocatalysts owing to their potential for incredible performance. However, uncertainty still exists in determining the correlation between grain boundaries (GBs) and photocatalytic activity. Therefore, effective thought has been put into engineering the GBs to convert ZNF into a promising photocatalyst. Herein, the obtained electrospun ZnO structures are composed of nanograins, which are connected to each other in an ordered manner. In-depth studies have revealed that the growth of nanograins severely altered the morphology of ZNF and GB areas at higher annealing temperatures ranging from 500 °C to 1000 °C. Based on the morphological features and their structural evolution, the obtained structures are named as ZnO nanofibers-1 (ZNF-1, 500 °C), ZnO hollow tubes (ZHT, 600 °C), ZnO nanofibers-2 (ZNF-2, 700 °C), ZnO bamboo structured fibers (ZBF, 800 °C), ZnO segmented fibers (ZSF, 900 °C) and ZnO nanoparticles (ZNP, 1000 °C). A strong correlation between the inherent emission features of ZNF and their peak positions have been detected with the GB. The comparative degradation efficiency of methylene blue (MB) has been studied and the results showed that the ZNF-1 with highly stacked nanograins containing rich grain boundaries demonstrated ∼6 times higher efficiency than other structures. In addition, it has been shown to have a strong effect towards the degradation of Rhodamine B (Rh B) and 4-nitro-phenol (4-NP). A critical parameter for improving the photocatalytic activity is found to be the GB mediated defects, which are proposed to be oxygen/zinc vacancies at nanograin fusion interfaces, while supposedly maintaining its fibrous structure, wherein no relationship has been drawn implying the direct domination of morphology, surface area and defect. [ABSTRACT FROM AUTHOR]

Here, we have put in conscientious effort to demonstrate the careful design of binding sites in fibers and their stability for enhanced adsorption of metal ions, which has proven to be a challenging task until now. Dithiothreitol capped gold nanoclusters (AuNCs) are successfully encapsulated into a cavity in the form of pores in electrospun porous cellulose acetate fibers (pCAFs) and their assembly creates a “nanotrap” for effective capture of Pb2+. The enhanced immobilization capacity of AuNCs into the interiors of the fibers and their non-aggregated nature offer enhanced adsorption sites, thus reaching maximum extraction capacity up to 1587 mg g−1 for Pb2+. The remarkable finding from this approach has shown that the diffusion of Pb2+ into the interiors of the AuNC encapsulated porous cellulose acetate fiber (pCAF/AuNC) is in line with the penetration depth of AuNCs. The effectiveness of the pCAF/AuNC has been compared with that of the AuNC decorated non-porous cellulose acetate fibers (nCAF/AuNC). The findings have shown a remarkable improvement in the adsorption efficiency by increasing the availability and stability of adsorption sites in the pCAF/AuNC. We strongly believe that the proposed approach might provide a new insight into developing nanotraps to eliminate the usual limitations including denaturation of adsorbents on supported matrices. [ABSTRACT FROM AUTHOR]

This study demonstrates the acute toxicity of lanthanum oxide nanoparticles (La2O3 NP) on two sentinel aquatic species, fresh-water microalgae Chlorella sp. and the crustacean Daphnia magna. The morphology, size and charge of the nanoparticles were systematically studied. The algal growth inhibition assay confirmed absence of toxic effects of La2O3 NP on Chlorella sp., even at higher concentration (1000 mg L−1) after 72 h exposure. Similarly, no significant toxic effects were observed on D. magna at concentrations of 250 mg L−1 or less, and considerable toxic effects were noted in higher concentrations (effective concentration [EC50] 500 mg L−1; lethal dose [LD50] 1000 mg L−1). In addition, attachment of La2O3 NP on aquatic species was demonstrated using microscopy analysis. This study proved to be beneficial in understanding acute toxicity in order to provide environmental protection as part of risk assessment strategies. [ABSTRACT FROM AUTHOR]

Here we demonstrate the combination of electrospinning and hollow cathode plasma-assisted atomic layer deposition (HCPA-ALD) processes by fabricating flexible polymer–GaN organic–inorganic core–shell nanofibers at a processing temperature much lower than that needed for the preparation of conventional GaN ceramic nanofibers. Polymer–GaN organic–inorganic core–shell nanofibers fabricated by the HCPA-ALD of GaN on electrospun polymeric (nylon 6,6) nanofibers at 200 °C were characterized in detail using electron microscopy, energy dispersive X-ray analysis, selected area electron diffraction, X-ray diffraction, X-ray photoelectron spectroscopy, photoluminescence measurements, and dynamic mechanical analysis. Although transmission electron microscopy studies indicated that the process parameters should be further optimized for obtaining ultimate uniformity and conformality on these high surface area 3D substrates, the HCPA-ALD process resulted in a ∼28 nm thick polycrystalline wurtzite GaN layer on polymeric nanofibers of an average fiber diameter of ∼70 nm. Having a flexible polymeric core and low processing temperature, these core–shell semiconducting nanofibers might have the potential to substitute brittle ceramic GaN nanofibers, which have already been shown to be high performance materials for various electronic and optoelectronic applications. [ABSTRACT FROM AUTHOR]

In this communication, a fluorescent gold cluster incorporated electrospun nanofibrous membrane and single nanofiber for selective and sensitive detection of TNT at sub-ppt level are demonstrated. [ABSTRACT FROM AUTHOR]

Hydrogen is an attractive alternative to fossil fuels in terms of environmental and other advantages. Of the various production methods for H2, photocatalysis requires further development so that it can be applied economically on an industrial scale. One- and two-dimensional nanostructures in both pristine and modified forms have shown great potential as catalysts in the generation of H2. We review here recent developments in these nanostructure catalysts and their efficiency in the generation of H2 under UV/visible/simulated solar light. Despite much research effort, many photocatalysts do not yet meet the practical requirements for the generation of H2, such as visible light activity. H2 production is dependent on a variety of parameters and factors. To meet future energy demands, several challenges in H2 production still need to be solved. We address here the factors that influence the efficiency of H2 production and suggest alternatives. The nanostructures are classified based on their morphology and their efficiency is considered with respect to the influencing parameters. We suggest effective ways of engineering catalyst combinations to overcome the current performance barriers. [ABSTRACT FROM AUTHOR]

We report on electron phonon interactions in bulk layered graphene (GRA) and its oxide (GO) under bias when exposed to 1° or 2° alcohol vapors, where we have focused on the change of Raman intensity of G and D bands as a function of the bias across the device. In addition to the softening of phonons we have observed a systematic variation in the intensity for D and G bands which is directly related to guest molecules and intrinsic surface nature of GRA and GO. Although the guest molecules withdraw electrons from GRA or GO, the intrinsic nature of the host material has caused mutually contrasting behaviour in IV-characteristics, where the conductance of the former decreases while it increases for the latter. The results from IV-spectra and the intensity maps of D and G bands are juxtaposed and the changes are analyzed with respect to surface and functional group interactions. In the context of doping, it is interesting to see that under equilibrium molecular charge transfer (top-gate like), the intensity ratios of 2D and G bands are not constant in contrast to a previous study [Phys. Rev. B., 2009, 80, 165413] in which such a ratio is invariant in the field effect configuration. [ABSTRACT FROM AUTHOR]

2D crystals such as graphene and its oxide counterpart have sought good research attention for their application as well as fundamental interest. Especially graphene oxide (GO) is quite interesting because of its versatility and diverse application potential. However the mechanism of fluorescence from GO is under severe discussion. To explain the emission in general two interpretations were suggested, viz localization of sp2 clusters and involvement of oxygeneous functional groups. Despite this disagreement, it should be acknowledged that the heterogeneous atomic structure, synthesis dependent and uncontrollable implantation of oxygen functional groups on the basal plane make such explanations more difficult. Nevertheless, a suitable explanation enhances the applicability of the material which also enables the design of novel materials. At this juncture we believe that given the complexity in understanding the emission mechanism it would be very useful to review the literature. In this perspective we juxtapose various results related to fluorescence and influencing factors so that a conclusive interpretation may be unveiled. Apparently, the existing interpretations have largely ignored the factors such as self-rolling, byproduct formation etc. Vis-a-vis previous reviews did not discuss the interfacial charge transfer across heterostructures and the implication on the optical properties of GO or reduced graphene oxide (rGO). Such analysis would be very insightful to determine the energetic location of sub band gap states. Moreover, ionic and π–π type interactions are also considered for their influence on emission properties. Apart from these, quantum dots, covalent modifications and nonlinear optical properties of GO and rGO were discussed for completeness. Finally we made concluding remarks with outlook. [ABSTRACT FROM AUTHOR]

A novel biocomposite material was developed by immobilizing an ammonia-oxidizing bacterial strain, Acinetobacter calcoaceticus STB1, on an electrospun porous cellulose acetate (CA) nanofibrous web. Ammonium removal characteristics of the STB1 immobilized CA nanofibrous web were determined at varying initial ammonium concentrations, and removal rates of 100%, 98.5% and 72% were observed within 48 h for 50 mg L−1, 100 mg L−1 and 200 mg L−1 samples, respectively. Most of the ammonia is inferred to be converted into nitrogen or is accumulated as bacterial biomass, as only trace amounts of ammonium were converted into nitrite or nitrate. Reusability test results indicate that, at an initial ammonium concentration of 100 mg L−1, bacteria-immobilized CA nanofibrous webs can be reused for at least 5 cycles. SEM images of the STB1/CA nanofibrous web after five cycles of reuse and rigorous washing demonstrate that bacterial biofilms strongly adhere to nanofiber surfaces. [ABSTRACT FROM AUTHOR]

Correction for ‘Flexible and highly stable electrospun nanofibrous membrane incorporating gold nanoclusters as an efficient probe for visual colorimetric detection of Hg(ii)’ by Anitha Senthamizhan et al., J. Mater. Chem. A, 2014, 2, 12717–12723. [ABSTRACT FROM AUTHOR]

Naproxen is a well-known non-steroidal anti-inflammatory drug (NSAID) that suffers from limited water solubility. The inclusion complexation with cyclodextrin (CD) can eliminate this drawback and the free-standing nanofibrous film (NF) generated from these inclusion complexes (ICs) can be a promising alternative formula as an orally disintegrating drug delivery system. For this, naproxen/CD IC NFs were generated using the highly water soluble hydroxypropylated derivative of βCD (HPβCD) with two different molar ratios of 1/1 and 1/2 (drug/CD). The complexation energy calculated by the modeling study demonstrated a more favorable interaction between HPβCD and naproxen for the 1/2 molar ratio than 1/1. HPβCD/naproxen IC NFs were generated with loading concentrations of ∼7-11% and without using toxic chemicals. HPβCD/naproxen IC NFs indicated a faster and enhanced release profile in aqueous medium compared to pure naproxen owing to inclusion complexation. Moreover, rapid disintegration in less than a second was achieved in an artificial saliva environment., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The electrospinning of hydrocortisone/cyclodextrin complex nanofibers was performed in order to develop a fast-dissolving oral drug delivery system. Hydrocortisone is a water-insoluble hydrophobic drug, yet, the water solubility of hydrocortisone was significantly enhanced by inclusion complexation with hydroxypropyl-beta-cyclodextrin (HP-β-CyD). In this study, hydrocortisone/HP-β-CyD complexes were prepared in aqueous solutions having molar ratios of 1/1, 1/1.5 and 1/2 (hydrocortisone/HP-β-CyD). Highly concentrated aqueous solutions of HP-β-CyD (180%, w/v) were used for hydrocortisone/HP-β-CyD systems (1/1, 1/1.5 and 1/2) in order to perform electrospinning without the use of an additional polymer matrix. The turbidity of hydrocortisone/HP-β-CyD (1/1 and 1/1.5) aqueous solutions indicated the presence of some uncomplexed crystals of hydrocortisone whereas the aqueous solution of hydrocortisone/HP-β-CyD (1/2) was homogeneous indicating that hydrocortisone becomes totally water-soluble by inclusion complexation with HP-β-CyD. Nonetheless, the electrospinning of hydrocortisone/HP-β-CyD systems (1/1, 1/1.5 and 1/2) successfully yielded defect-free uniform nanofibrous structures. Moreover, the electrospinning process was quite efficient that hydrocortisone was completely preserved without any loss yielding hydrocortisone/HP-β-CyD nanofibers having the initial molar ratios (1/1, 1/1.5 and 1/2). The structural and thermal characterization of the hydrocortisone/HP-β-CyD nanofibers revealed that hydrocortisone was totally inclusion complexed with HP-β-CyD and was in the amorphous state in hydrocortisone/HP-β-CyD (1/2) nanofibers whereas some uncomplexed crystalline hydrocortisone was present in hydrocortisone/HP-β-CyD (1/1 and 1/1.5) nanofibers. Nevertheless, hydrocortisone/HP-β-CyD (1/1, 1/1.5 and 1/2) complex aqueous systems were electrospun in the form of nanofibrous webs having a free-standing and flexible nature. The hydrocortisone/HP-β-CyD (1/1, 1/1.5 and 1/2) nanofibrous webs have shown fast-dissolving behavior in water or when they were in contact with artificial saliva. Yet, the hydrocortisone/HP-β-CyD (1/2) nanofibrous web dissolved more quickly than the hydrocortisone/HP-β-CyD (1/1 and 1/1.5) nanofibrous webs due to the full inclusion complexation and the amorphous state of hydrocortisone in this sample. In short, the results suggest that polymer-free electrospun nanofibrous webs produced from hydrocortisone/HP-β-CyD could be quite applicable for fast-dissolving oral drug delivery systems., (This journal is © The Royal Society of Chemistry 2020.)

Smart, stimuli-responsive, photoluminescent materials that undergo a visually perceptible emission color change in the presence of an external stimulus have long been attractive for use in sensor platforms. When the stimulus is the presence of water, the materials that undergo changes in their light emission properties are called hydrochromic and they can be used for the development of sensors to detect and quantify the water content in organic solvents, which is fundamental for laboratory safety and numerous industrial applications. Herein, we demonstrate the preparation of structurally different carbon dots with tunable emission wavelengths via a simple carbonization approach under controlled temperature and time, involving commercial brown sugar as a starting material. The detailed experimental analysis reveals the "structure-hydrochromic property" relationship of the carbon dots and assesses their capability as effective water sensors. The carbon dots that were proved most efficient for the specific application were then used to identify the presence of water in various aprotic and protic organic solvents via a sensing mechanism based either on the fluorescence wavelength shift or on the fluorescence intensity enhancement, respectively, attributed to the formation of intermolecular hydrogen bonds between carbon dots and water molecules. This is the first demonstration of structurally defined carbon dots in a specific application. The developed carbon dots, apart from being environmentally friendly, were proved to also be biocompatible, enabling this presented process to be a path to "green" sensors., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are considered as the two crucial reactions in key renewable-energy technologies including fuel cells and water splitting. Despite promising research progress in the preparation of various non-noble metal based electrocatalysts, it is still highly challenging but desirable to develop novel fabrication strategies to synthesize highly active and cost-effective ORR/OER bifunctional electrocatalysts in a precisely controlled manner. Herein, we report atomic layer deposition (ALD) of highly monodisperse Co 3 O 4 nanocrystals of different sizes on N-doped electrospun carbon nanofibers (nCNFs) as high performance bifunctional catalysts (Co@nCNFs) for the ORR and OER. Co@nCNFs (with an average Co 3 O 4 particle size of ∼3 nm) show high ORR performance exhibiting an onset potential of 0.87 V with a low Tafel slope of 119 mV dec -1 approaching that of commercial Pt/C. Similarly, the Co@nCNF electrocatalyst showed remarkable catalytic activity in the OER. The turnover frequency (TOF) value determined at an overpotential of 550 mV for the Co@nCNFs is ∼0.14 s -1 which is ca. 3 and ca. 15-fold higher than those of bulk Co (∼0.05 s -1 ) and the standard state-of-the-art IrO x (0.0089 s -1 ) catalyst, respectively. This work will open new possibilities for fabrication of inexpensive non-noble metal materials in highly controlled manner for applications as bifunctional ORR/OER electrocatalysis., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

This study demonstrates the acute toxicity of lanthanum oxide nanoparticles (La2O3 NP) on two sentinel aquatic species, fresh-water microalgae Chlorella sp. and the crustacean Daphnia magna. The morphology, size and charge of the nanoparticles were systematically studied. The algal growth inhibition assay confirmed absence of toxic effects of La2O3 NP on Chlorella sp., even at higher concentration (1000 mg L(-1)) after 72 h exposure. Similarly, no significant toxic effects were observed on D. magna at concentrations of 250 mg L(-1) or less, and considerable toxic effects were noted in higher concentrations (effective concentration [EC50] 500 mg L(-1); lethal dose [LD50] 1000 mg L(-1)). In addition, attachment of La2O3 NP on aquatic species was demonstrated using microscopy analysis. This study proved to be beneficial in understanding acute toxicity in order to provide environmental protection as part of risk assessment strategies.

We have demonstrated that cyclodextrin (CD) (a non-polymeric system) can be electrospun into nanofibers by itself; methyl-beta-cyclodextrin (MbetaCD) nanofibers were electrospun and it was observed that the success of the electrospinning of the CD nanofibers strongly depends on (i) type of solvent, (ii) CD solution concentration and (iii) intermolecular interactions between the CD molecules.