Dean Cardillo

Liquid Crystalline Graphene Oxide/PEDOT:PSS Self-Assembled 3D Architecture for Binder-Free Supercapacitor Electrodes

Binder-free self-assembled 3D architecture electrodes have been fabricated by a novel convienient method. Liquid crystalline graphene oxide (LC GO) was used as precursor to interact with poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) in dispersion in order to form a conductive polymer entrapped, self-assembled layer-by-layer structure. This advanced network containing PEDOT:PSS enabled us to ascribe the superior electrochemical properties of particular graphene sheets. This layer-by-layer self-assembled 3D architecture of best performing composite (rGO-PEDOT:PSS 25) showed excellent electrochemical performance of 434 F g-1 through chemical treatment. To highlight these advances, we further explored the practicality of the as-prepared electrode by varying the composite material content. An asymmetric supercapacitor device using aqueous electrolyte was also studied of this same composite. The resulting performance from this set up included a specific capacitance of 132 F g-1. Above all, we observed an increase in specific capacitance (19%) with increase in cycle life emphasizing the excellent stability of this device.

Self-Assembled Multifunctional Hybrids: Toward Developing High-Performance Graphene-Based Architectures for Energy Storage Devices.

The prospect of developing multifunctional flexible three-dimensional (3D) architectures based on integrative chemistry for lightweight, foldable, yet robust, electronic components that can turn the many promises of graphene-based devices into reality is an exciting direction that has yet to be explored. Herein, inspired by nature, we demonstrate that through a simple, yet novel solvophobic self-assembly processing approach, nacre-mimicking, layer-by-layer grown, hybrid composite materials (consisting of graphene oxide, carbon nanotubes, and conducting polymers) can be made that can incorporate many of the exciting attributes of graphene into real world materials. The as-produced, self-assembled 3D multifunctional architectures were found to be flexible, yet mechanically robust and tough (Young’s modulus in excess of 26.1 GPa, tensile strength of around 252 MPa, and toughness of 7.3 MJ m–3), and exhibited high native electrical conductivity (38700 S m–1) and unrivalled volumetric capacitance values (761 F cm–3) with excellent cyclability and rate performance.

Synthesis-Dependent Surface Defects and Morphology of Hematite Nanoparticles and Their Effect on Cytotoxicity in Vitro

In this study, we investigate the toxicity of hematite (α-Fe2O3) nanoparticles on the Madin-Darby Canine Kidney (MDCK) cell line. The oxide particles have been synthesized through two different methods and annealing conditions. These two methods, spray precipitation and precipitation, resulted in particles with rod-like and spherical morphology and feature different particle sizes, surface features, and magnetic properties. Through flow cytometry it was found that particle morphology heavily influences the degree to which the nanomaterials are internalized into the cells. It was also found that the ability of the nanoparticles to generate free radicals species is hindered by the formation of tetrahedrally coordinated maghemite-like (γ-Fe2O3) spinel defects on the surfaces of the particles. The combination of these two factors resulted in variable cytotoxic effects of the hematite nanoparticles synthesized with different conditions. This article highlights the importance on the fabrication method, materials properties, and surface characteristics on the cytotoxicity of hematite nanomaterials.

A chemically modified graphene oxide wrapped porous hematite nano-architecture as a high rate lithium-ion battery anode material

Successful fabrication of nanoporous metal oxides with carbonaceous nanomaterials can enhance the conductivity of electrodes as well as advance their electrochemical activity to overcome the stress induced during continuous charge–discharge cycling, and this is an effective way to harness their excellent reversible theoretical capacity. Nanoporous hematite (α-Fe2O3) nanorods have been prepared through an advanced spray precipitation method and nanofabricated with reduced graphene oxide (rGO) sheets by simply mixing solutions. This approach helps to introduce a continuous conductive network in between the nanorods to enhance ion interactions, giving the composite a promising electrochemical response as a negative electrode for the lithium-ion battery (LIB). The nanocomposites delivered an outstanding reversible capacity of 1330 mA h g−1 at 100 mA g−1 for 100 cycles and showed excellent rate retention during cycling at different current densities over long cycle numbers, highlighting the potential of this material with its specially designed nano-architecture as an anode material for high energy LIBs for electric vehicles. Along with the overwhelming electrochemical performance of chemically modified graphene-oxide-wrapped hematite porous nanorods (α-Fe2O3/rGO), the abundance of the hematite source, and the advanced and environmentally friendly synthesis approach show the potential for large-scale preparation of such electrode materials for real world application.

Multifunctional Fe2O3/CeO2 nanocomposites for free radical scavenging ultraviolet protection

In this study we synthesized Fe2O3/CeO2 composite nanoparticles for application as multifunctional ultraviolet (UV) filters. The precipitation of small ceria (CeO2) nanoparticles onto the surface of larger hematite (α-Fe2O3) nanoparticles, results in stronger and more selective absorbance in the (UV) region. Through UV photocatalyst experiments, we show that the addition of these nanocomposite particles significantly reduces the degradation of crystal violet by P25 by scavenging the photogenerated OH˙ radicals.

Synthesis of nitrogen-doped graphene via thermal treatment of graphene oxide within methylimidazole and its capacitance performance as electric double layer capacitor

Nitrogen-doped graphene was successfully synthesised from graphene oxide (GO) and 2-methylimidazole composite via thermal treatment under argon flow at 700oC within 1h. This synthesised N-doped graphene exhibits homogeneous nitrogen doping with concentration of ~5% in three different nitrogen configuration namelypyridinic N, pyrrolic N and graphitic N. The electric double layer capacitor (EDLC) made up with this N-doped graphene showed excellent specific capacitance 274 F/g at current density of 1A/g, which was ~7 times higher than GO. This EDLC capacitor showed excellent cyclic stability up to 5000 cycles with capacity

High toxicity of Bi(OH)3 and α-Bi2O3 nanoparticles towards malignant 9L and MCF-7 cells

Here we report the extreme toxicity in vitro of Bi(OH)3 and α-Bi2O3 nanoparticles (NPs), obtained through a facile synthesis with an average single particle size of 6-10 nm, tested on malignant gliosarcoma 9L and MCF-7 human breast cancer cells. For both nanomaterials, clonogenic assays reveal a mortality of over 90% in 9L and MCF-7 cells for a concentration of 50 μg/mL after incubation for 24 h. Moreover, the NPs show a significant mortality of up to 60% in the malignant cells at the very low concentration of 6.25 μg/mL. In contrast, at the same concentration, the nanomaterials exhibit no noticeable mortality towards normal Madin-Darby canine kidney cells. The internalisation of the NPs was demonstrated using flow cytometry and confocal microscopy was used to investigate when the loss of cell viability starts. The NPs show a faster cell death in 9L cells compared with MCF-7 cells, demonstrated via the identification of apoptosis through increased sub G1 levels after 24 h of NP incubation. Cleavage is identified as the main apoptotic nuclear morphology in 9L, which suggests the presence of reactive oxygen species.