ABSTRACT
Carbon nanomaterials derived from agricultural waste streams present an exciting material platform that hits multiple sustainability targets by reducing waste entering landfill, and enabling clean energy and environmental remediation technologies. In this work, the energy and photocatalytic properties of reduced graphene oxide fabricated from coconut coir using a simple reduction method using ferrocene are substantially improved by introducing metallic oxides flakes. A series of cobalt ferrite rGO/CoFe2O4 nanocomposites were assembled using a simple soft bubble self-templating assembly, and their potential for clean energy applications confirmed. The transmission electron microscopy images revealed the uniform dispersion of the metal oxide on the rGO sheets. The functional group of the as synthesized metal oxide and the rGO nanocomposites, and its individual constituents, were identified through the FTIR and XPS studies, respectively. The composite materials showed higher specific capacitance then the pure materials, with rGO spinal metal oxide nanocomposites showing maximum specific capacitance of 396 F/g at 1 A/g. Furthermore, the hybrid super capacitor exhibits the excellent cyclic stability 2000 cycles with 95.6% retention. The photocatalytic properties of the synthesized rGO nanocomposites were analyzed with the help of malachite green dye. For pure metal oxide, the degradation rate was only around 65% within 120 min, while for rGO metal oxide nanocomposites, more than 80% of MG were degraded.
ABSTRACT
This present study reports the development of novel catalyst support of amine terminated cyclophosphazene/cyclophosphazene/hexafluoroisopropylidenedianiline-carbon nanotube (ATCP/CP/HFPA-CNT) composite. The ATCP/CP/HFPA-CNT composite has been used as a catalyst support for platinum (Pt) and platinum-gold (Pt-Au) nanoparticles towards electrooxidation of methanol in alkaline medium. The obtained anode materials were characterized by X-ray diffraction, transmission electron microscope and energy dispersive X-ray analysis. Electrocatalytic performances of Pt/ATCP/CP/HFPA-CNT and Pt-Au/ATCP/CP/HFPA-CNT catalysts were investigated by cyclic voltammetry, CO stripping and chronoamperometric techniques. The electrooxidation of methanol and CO stripping results conclude that the metal nanocatalyst embedded with ATCP/CP/HFPA-CNT composite shows significantly higher anodic oxidation current, more CO tolerance and lower onset potential when compared to that of the Pt/CNT and Pt/C (Vulcan carbon) catalysts.
ABSTRACT
The synthesis and characterization of catalysts based on nanomaterials, supported on multi-walled carbon nanotubes (CNT) for ethylene glycol (EG) oxidation is investigated. Platinum (Pt) and platinum-ruthenium (Pt-Ru) nanoparticles are deposited on surface-oxidized multi-walled carbon nanotubes [Pt/CNT; Pt-Ru/CNT] by the aqueous solution reduction of the corresponding metal salts with glycerol. The electrocatalytic properties of the modified electrodes for oxidation of ethylene glycol in acidic solution have been studied by cyclic voltammetry (CV), and excellent activity is observed. This may be attributed to the small particle size of the metal nanoparticles, the efficacy of carbon nanotubes acting as good catalyst support and uniform dispersion of nanoparticles on CNT surfaces. The nature of the resulting nanoparticles decorated multiwalled carbon nanotubes are characterized by scanning electron microscopy (SEM) and transmission electron microscopic (TEM) analysis. The cyclic voltammetry response indicates that Pt-Ru/CNT catalyst displays a higher performance than Pt/CNT, which may be due to the efficiency of the nature of Ru species in Pt-Ru systems. The fabricated Pt and Pt-Ru nanoparticles decorated CNT electrodes shows better catalytic performance towards ethylene glycol oxidation than the corresponding nanoparticles decorated carbon electrodes, demonstrating that it is more promising for use in fuel cells.
ABSTRACT
A novel supporting material containing polythiophene (PTh) and multiwalled carbon nanotubes (MWCNTs) (PTh-CNTs) is prepared by in situ polymerization of thiophene on carbon nanotubes using FeCl(3) as oxidizing agent under sonication. The prepared polythiophene/CNT composites are further decorated with Pt and Pt-Ru nanoparticles by chemical reduction of the corresponding metal salts using HCHO as reducing agent at pH = 11 (Pt/PTh-CNT and Pt-Ru/PTh-CNT). The fabricated composite films decorated with nanoparticles were investigated towards the electrochemical oxidation of ethylene glycol (EG). The presence of carbon nanotubes in conjugation with a conducting polymer produces a good catalytic effect, which might be due to the higher electrochemically accessible surface areas, electronic conductivity and easier charge-transfer at polymer/electrolyte interfaces, which allows higher dispersion of Pt and Pt-Ru nanoparticles. Such nanoparticle modified PTh-CNT electrodes exhibit better catalytic behavior towards ethylene glycol oxidation. Results show that Pt/PTh-CNT and Pt-Ru/PTh-CNT modified electrodes show enhanced electrocatalytic activity and stability towards the electro-oxidation of ethylene glycol than the Pt/PTh electrodes, which shows that the composite film is more promising for applications in fuel cells.
ABSTRACT
Gold nanoparticles are reported and evaluated as probes for the detection of anticancer drug 5-fluorouracil (5FU). The nature of binding between 5FU and gold nanoparticles via complexation is investigated using ultraviolet visible spectrophotometry, cyclic voltammetry, transmission electron microscopy, fluorescence and Fourier transform infrared (FTIR) spectroscopy. The bound antileukemic drug is fluorescent and the quenching property of gold nanoparticles could be exploited for biological investigations. The 5FU-colloidal gold complex (Au@5FU) is observed to have appreciable antibacterial and antifungal activity against Micrococcus luteus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Aspergillus fumigatus, and Aspergillus niger. The experimental studies suggest that gold nanoparticles have the potential to be used as effective carriers for anticancer drugs.
