Hierarchically mesoporous CuO/carbon nanofiber coaxial shell-core nanowires for lithium ion batteries

Ultrasensitive detection of cytotoxic food preservative tert-butylhydroquinone using 3D cupric oxide nanoflowers embedded functionalized carbon nanotubes

Accurate detection of cytotoxic food preservative tert-butylhydroquinone (TBHQ) has significant importance in maintaining food quality and safety. TBHQ is a chronic hazard to aquatic life and its use in applications involving direct human exposure and frequent release to environment makes its quantification critical to maintain safety. Hence, we report development of a sensitive electrochemical sensor for TBHQ determination at nanomolar level in commonly used edible oils and water sample. Novel cupric oxide (CuO) decorated amine functionalized carbon nanotubes (NH₂-CNTs) were prepared for development of TBHQ sensor. 3D CuO nanoflowers and NH₂-CNTs were synthesized using hydrothermal and ultrasound-assisted method respectively. Techniques such as SEM, elemental mapping, XRD, FTIR, micro Raman, XPS, EIS, and UV-Visible spectroscopy were taken to affirm significant characterizations of synthesized materials. We have observed outstanding electrocatalytic activity towards TBHQ detection using the sonochemically prepared nanocomposite modified screen printed carbon electrode (SPCE). The proposed sensor exhibited ultra-low detection limit at 3 nM and exceptional sensitivity at 37.7 μA μM^-1 cm^-2. Furthermore, TBHQ sensor showcased outstanding anti-interference, stability, reproducibility, and repeatability. The practical feasibility of TBHQ detection was validated using real sample analysis resulting in excellent recovery in the range 95.90-104.87% and a maximum RSD of mere 2.71%.

Core-shell nanostructures: perspectives towards drug delivery applications

Nanosystems have shown encouraging outcomes and substantial progress in the areas of drug delivery and biomedical applications. However, the controlled and targeted delivery of drugs or genes can be limited due to their physicochemical and functional properties. In this regard, core-shell type nanoparticles are promising nanocarrier systems for controlled and targeted drug delivery applications. These functional nanoparticles are emerging as a particular class of nanosystems because of their unique advantages, including high surface area, and easy surface modification and functionalization. Such unique advantages can facilitate the use of core-shell nanoparticles for the selective mingling of two or more different functional properties in a single nanosystem to achieve the desired physicochemical properties that are essential for effective targeted drug delivery. Several types of core-shell nanoparticles, such as metallic, magnetic, silica-based, upconversion, and carbon-based core-shell nanoparticles, have been designed and developed for drug delivery applications. Keeping the scope, demand, and challenges in view, the present review explores state-of-the-art developments and advances in core-shell nanoparticle systems, the desired structure-property relationships, newly generated properties, the effects of parameter control, surface modification, and functionalization, and, last but not least, their promising applications in the fields of drug delivery, biomedical applications, and tissue engineering. This review also supports significant future research for developing multi-core and shell-based functional nanosystems to investigate nano-therapies that are needed for advanced, precise, and personalized healthcare systems.

A Review of Recent Advancements in Electrospun Anode Materials to Improve Rechargeable Lithium Battery Performance

Although lithium-ion batteries have already had a considerable impact on making our lives smarter, healthier, and cleaner by powering smartphones, wearable devices, and electric vehicles, demands for significant improvement in battery performance have grown with the continuous development of electronic devices. Developing novel anode materials offers one of the most promising routes to meet these demands and to resolve issues present in existing graphite anodes, such as a low theoretical capacity and poor rate capabilities. Significant improvements over current commercial batteries have been identified using the electrospinning process, owing to a simple processing technique and a wide variety of electrospinnable materials. It is important to understand previous work on nanofiber anode materials to establish strategies that encourage the implementation of current technological developments into commercial lithium-ion battery production, and to advance the design of novel nanofiber anode materials that will be used in the next-generation of batteries. This review identifies previous research into electrospun nanofiber anode materials based on the type of electrochemical reactions present and provides insights that can be used to improve conventional lithium-ion battery performances and to pioneer novel manufacturing routes that can successfully produce the next generation of batteries.

Growth of carbon nanofibres on molybdenum carbide nanowires and their self-decoration with noble-metal nanoparticles

High specific surface area makes carbon nanofibres suitable for catalyst support. Here we report on optimization of carbon nanofibre (CNF) growth on molybdenum carbide nanowires (MoCNW) by direct carburization ofMo 6 S 2 I 8 nanowire bundles. Typical CNFs obtained by this method are several hundreds of nanometres long at a diameter of 10-20 nm. We show that nanofibre growth does not depend on the initial morphology of the nanowires: nanofibres grow on individual bundles of MoCNW, on dense networks of nanowires deposited on silicon substrate, and on free-standing nanowire foils. We find that carbon nanofibres remain firmly attached to the nanowires even if they are modified intoMo 2 C and further into Mo S 2 nanowires. The method thus enables production of a novel hybrid material composed of Mo S 2 nanowires densely covered with carbon nanofibres. We have additionally shown that the obtained CNFs can easily be self-decorated with platinum nanoparticles with diameters of several nanometres directly from water solution at room temperature without reducing agents. Such efficient synthesis and decoration process yield hybrid platinum/CNF/molybdenum-based NW materials, which are a promising material for a wide range of possible future applications, including sensitive sensorics and improved catalysis.

One-Pot Decoration of Cupric Oxide on Activated Carbon Fibers Mediated by Polydopamine for Bacterial Growth Inhibition

Despite the widespread application of activated carbon fiber (ACF) filters in air cleaning owing to their high surface area and low price, they have certain limitations in that they facilitate bacterial growth upon prolonged use as ACF filters can provide favorable conditions for bacterial survival. The deposition of cupric oxide (CuO) on ACFs can be an effective way of resolving this problem because CuO can inhibit the proliferation of bacteria owing to its antimicrobial properties. However, finding a new method that allows the simple and uniform coating of CuO on ACF filters is challenging. Here, we demonstrate one-pot CuO deposition mediated by polydopamine (PD) to realize an ACF filter with antimicrobial activity. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) analyses reveal that CuO and PD are uniformly deposited on the ACF surface. The amount of CuO formed on the ACFs is measured by thermogravimetric analysis (TGA). Finally, the changes in surface area, pressure drop, and antimicrobial activity after coating PD-CuO on the ACFs are evaluated. The use of PD-CuO on the ACFs effectively suppresses the growth of bacteria and enhances the mechanical properties without significantly sacrificing the original characteristics of the ACF filter.

An efficient electrode material for high performance solid-state hybrid supercapacitors based on a Cu/CuO/porous carbon nanofiber/TiO2 hybrid composite

A Cu/CuO/porous carbon nanofiber/TiO2 (Cu/CuO/PCNF/TiO2) composite uniformly covered with TiO2 nanoparticles was synthesized by electrospinning and a simple hydrothermal technique. The synthesized composite exhibits a unique morphology and excellent supercapacitive performance, including both electric double layer and pseudo-capacitance behavior. Electrochemical measurements were performed by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The highest specific capacitance value of 530 F g-1 at a current density of 1.5 A g-1 was obtained for the Cu/CuO/PCNF/TiO2 composite electrode in a three-electrode configuration. The solid-state hybrid supercapacitor (SSHSC) fabricated based on this composite exhibits a high specific capacitance value of 330 F g-1 at a current density of 1 A g-1 with 78.8% capacitance retention for up to 10,000 cycles. At the same time, a high energy density of 45.83 Wh kg-1 at a power density of 1.27 kW kg-1 was also realized. The developed electrode material provides new insight into ways to enhance the electrochemical properties of solid-state supercapacitors, based on the synergistic effect of porous carbon nanofibers, metal and metal oxide nanoparticles, which together open up new opportunities for energy storage and conversion applications.

Single Step, Electrochemical Preparation of Copper-Based Positive Electrode for Lithium Primary Cells

Lithium primary cells are commonly used in applications where high energy density and low self-discharge are the most important factors. This include small coin cells for electronics, power backup batteries for complementary metal-oxide-semiconductor memory or as a long-term emergency power source. In our study we present a fast, electrochemical method of the positive electrode preparation for lithium primary cells. The influence of the current density and oxygen presence in a solution on the preparation of the electrode and thus its electrochemical behavior is examined. Electrode compositions were characterized by X-ray photoelectron spectroscopy (XPS). The prepared electrodes may be used in Li cells as competition to Zn-MnO₂ primary batteries.

Design of a Porous Cathode for Ultrahigh Performance of a Li-ion Battery: An Overlooked Pore Distribution

Typical cathode materials of Li-ion battery suffer from a severe loss in specific capacity, and this problem is regarded as a major obstacle in the expansion of newer applications. To overcome this, porous cathodes are being extensively utilized. However, although it seems that the porosity in the cathode would be a panacea for high performance of LIBs, there is a blind point in the cathode consisting of porous structures, which makes the porous design to be a redundant. Here, we report the importance of designing the porosity of a cathode in obtaining ultrahigh performance with the porous design or a degraded performance even with increase of porosity. Numerical simulations show that the cathode with 40% porosity has 98% reduction in the loss of specific capacity when compared to the simple spherical cathode when the C-rate increases from 2.5 to 80 C. In addition, the loss over total cycles decreases from 30% to only about 1% for the cathode with 40% porosity under 40 C. Interestingly, however, the specific capacity could be decreased even with the increase in porosity unless the pores were evenly distributed in the cathode. The present analysis provides an important insight into the design of ultrahigh performance cathodes.

Preparation of Advanced CuO Nanowires/Functionalized Graphene Composite Anode Material for Lithium Ion Batteries

The copper oxide (CuO) nanowires/functionalized graphene (f-graphene) composite material was successfully composed by a one-pot synthesis method. The f-graphene synthesized through the Birch reduction chemistry method was modified with functional group “–(CH₂)₅COOH”, and the CuO nanowires (NWs) were well dispersed in the f-graphene sheets. When used as anode materials in lithium-ion batteries, the composite exhibited good cyclic stability and decent specific capacity of 677 mA·h·g⁻¹ after 50 cycles. CuO NWs can enhance the lithium-ion storage of the composites while the f-graphene effectively resists the volume expansion of the CuO NWs during the galvanostatic charge/discharge cyclic process, and provide a conductive paths for charge transportation. The good electrochemical performance of the synthesized CuO/f-graphene composite suggests great potential of the composite materials for lithium-ion batteries anodes.

Dual-template ordered mesoporous carbon/Fe2O3 nanowires as lithium-ion battery anodes

Ordered mesoporous carbons (OMCs) are ideal host materials that can provide the desirable electrical conductivity and ion accessibility for high-capacity oxide electrode materials in lithium-ion batteries (LIBs). To this end, however, it is imperative to establish the correlations among material morphology, pore structure and electrochemical performance. Here, we fabricate an ordered mesoporous carbon nanowire (OMCNW)/Fe2O3 composite utilizing a novel soft-hard dual-template approach. The structure and electrochemical performance of OMCNW/Fe2O3 were systematically compared with single-templated OMC/Fe2O3 and carbon nanowire/Fe2O3 composites. This dual-template strategy presents synergetic effects combining the advantages of both soft and hard single-template methods. The resulting OMCNW/Fe2O3 composite enables a high pore volume, high structural stability, enhanced electrical conductivity and Li(+) accessibility. These features collectively enable excellent electrochemical cyclability (1200 cycles) and a reversible Li(+) storage capacity as high as 819 mA h g(-1) at a current density of 0.5 A g(-1). Our findings highlight the synergistic benefits of the dual-template approach to heterogeneous composites for high performance electrochemical energy storage materials.

Hydroxyl radical generation by cactus-like copper oxide nanoporous carbon catalysts for microcystin-LR environmental remediation

Copper oxide supported on nanoporous activated carbon (CuO-NPAC) is reported for the aqueous phase catalytic degradation of cyanotoxin microcystin-LR (MC-LR).

Effect of Mn3O4 nanoparticle composition and distribution on graphene as a potential hybrid anode material for lithium-ion batteries

Electrochemical performance of lithium-ion battery anodes can be enhanced by optimized inter-particle distance based on composition change.

Fabrication and characterization of continuous silver nanofiber/polyvinylpyrrolidone (AgNF/PVP) core–shell nanofibers using the coaxial electrospinning process

Core–shell silver nanofiber/polyvinylpyrrolidone (AgNF/PVP) nanofibers have been successfully fabricated via an efficient coaxial-spinneret electrospinning method with a vertical configuration using PVP and AgNO₃ as precursor solutions.

Preparation of a nanoporous CuO/Cu composite using a dealloy method for high performance lithium-ion batteries

A nanoporous CuO/Cu composite material was prepared using a dealloy method, and exhibited excellent cycling stability when evaluated as an anode for lithium-ion batteries.

Significant enhancement of the electroactive β-phase of PVDF by incorporating hydrothermally synthesized copper oxide nanoparticles

The influence of copper oxide nanoparticles on the polymorphism of PVDF is systematically investigated. Strong interfacial interactions between the negative nanoparticle surface and positive –CH₂ dipoles of PVDF enhance the electroactive β-phase.