Preparation and characterization of magnetic Fe3O4/CdWO4 and Fe3O4/CdWO4/PrVO4 nanoparticles and investigation of their photocatalytic and anticancer properties on PANC1 cells

Fe3O4/CdWO4 and Fe3O4/CdWO4/PrVO4 magnetic nanoparticles were prepared at different molar ratios of PrVO4 to previous layers (Fe3O4/CdWO4) via the co-precipitation method assisted by a sonochemical procedure, in order to investigate the photocatalytic performance of these systems and their cytotoxicity properties. The physico-chemical properties of these magnetic nanoparticles were determined via several experimental methods: X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier transformation infrared spectroscopy and ultraviolet-visible diffuse reflection spectroscopy, using a vibrating sample magnetometer and a scanning electron microscope. The average sizes of these nanoparticles were found to be in the range of 60-100 nm. The photocatalytic efficiency of the prepared nanostructures was measured by methylene blue degradation under visible light (assisted by H2O2). The magnetic nanosystem with a 1:2:1 ratio of three oxide components showed the best performance by the degradation of ca. 70 after 120 min of exposure to visible light irradiation. Afterwards, this sample was used for the photodegradation of methyl orange, methyl violet, fenitrothion, and rhodamine-B pollutants. Finally, the mechanism of the photocatalytic reaction was examined by releasing �OH under UV light in a system including terephthalic acid, as well as O2-, OH, and hole scavengers. Additionally, the cytotoxicity of each synthesized sample was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay against the human cell line PANC1 (cancer), and its IC50 was approximately 125 mg/L. © 2019 by the authors

Synthesis of magnetic fe3o4/znwo4 and fe3o4/znwo4/cevo4 nanoparticles: The photocatalytic effects on organic pollutants upon irradiation with uv-vis light

Magnetic Fe3O4/ZnWO4 and Fe3O4/ZnWO4/CeVO4 nanoparticles with different molar ratios of CeVO4 to other inorganic components were synthesized through co-precipitation with a sonochemical-assisted method. X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, vibrating sample magnetometry, and scanning electron microscopy (SEM) methods were used for the physico�chemical characterization of the obtained nanoparticles. As shown in the SEM images, the average sizes of the Fe3O4 /ZnWO4 and Fe3O4 /ZnWO4 /CeVO4 nanoparticles that formed aggregates were approximately 50�70 nm and 80�100 nm, respectively. The photocatalytic performance of these nanoparticles was examined by measuring methylene blue degradation under visible light (assisted by H2O2). The sample with a mass ratio of 1:2:1 (Fe3O4/ZnWO4/CeVO4, S4) exhibited optimal photocatalytic performance, and thus this sample was subsequently used for the photodegradation of different organic pollutants upon irradiation with ultraviolet (UV) and visible light. Approximately 90 and 70 degradation of methyl violet and methylene blue, respectively, was observed after visible light irradiation. Additionally, the mechanism of the photocatalytic reaction was investigated by measuring ·OH release under UV light in a system with terephthalic acid and by measuring the release of·O2 �,·OH, and hole scavengers. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Synthesis of magnetic fe3o4/znwo4 and fe3o4/znwo4/cevo4 nanoparticles: The photocatalytic effects on organic pollutants upon irradiation with uv-vis light

Magnetic Fe3O4/ZnWO4 and Fe3O4/ZnWO4/CeVO4 nanoparticles with different molar ratios of CeVO4 to other inorganic components were synthesized through co-precipitation with a sonochemical-assisted method. X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, vibrating sample magnetometry, and scanning electron microscopy (SEM) methods were used for the physico�chemical characterization of the obtained nanoparticles. As shown in the SEM images, the average sizes of the Fe3O4 /ZnWO4 and Fe3O4 /ZnWO4 /CeVO4 nanoparticles that formed aggregates were approximately 50�70 nm and 80�100 nm, respectively. The photocatalytic performance of these nanoparticles was examined by measuring methylene blue degradation under visible light (assisted by H2O2). The sample with a mass ratio of 1:2:1 (Fe3O4/ZnWO4/CeVO4, S4) exhibited optimal photocatalytic performance, and thus this sample was subsequently used for the photodegradation of different organic pollutants upon irradiation with ultraviolet (UV) and visible light. Approximately 90 and 70 degradation of methyl violet and methylene blue, respectively, was observed after visible light irradiation. Additionally, the mechanism of the photocatalytic reaction was investigated by measuring ·OH release under UV light in a system with terephthalic acid and by measuring the release of·O2 �,·OH, and hole scavengers. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Combined high permittivity and high electrical conduc-tivity of carbon nano-onion/polyaniline composites

We report high dielectric permittivity values for electrically conducting carbon nano-onion/polyaniline (CNO/PANI) composites. Broadband Dielectric Spectroscopy (BDS) measurements conducted under isothermal conditions from 16 K to room temperature in the frequency range between 1 mHz and 1 MHz, revealed a Cole-Cole relaxation mechanism. The intensity of the relaxation is comparable with the observed huge static dielectric constant values, and indicates a correlation between the intense capacitance effects and the relaxation. The relaxation dynamics involve single or two phonon assisted tunneling of the relaxing electric charge carriers (protons and electrons) at low temperatures, which transition to multi-phonon assisted tunneling relaxation above 100 K. Within the Mott-Davis model describing phonon-assisted tunneling relaxation in disordered media, the typical spatial scale relaxation occurs and is found to correlate with the size of the CNOs. The capacitance correlates with the large effective CNO surface areas. © 2015 Elsevier B.V. All rights reserved

Electric properties of carbon nano-onion/polyaniline composites: A combined electric modulus and ac conductivity study

The complex electric modulus and the ac conductivity of carbon nano-onion/polyaniline composites were studied from 1 mHz to 1 MHz at isothermal conditions ranging from 15 K to room temperature. The temperature dependence of the electric modulus and the dc conductivity analyses indicate a couple of hopping mechanisms. The distinction between thermally activated processes and the determination of cross-over temperature were achieved by exploring the temperature dependence of the fractional exponent of the dispersive ac conductivity and the bifurcation of the scaled ac conductivity isotherms. The results are analyzed by combining the granular metal model (inter-grain charge tunneling of extended electron states located within mesoscopic highly conducting polyaniline grains) and a 3D Mott variable range hopping model (phonon assisted tunneling within the carbon nano-onions and clusters). © 2016 IOP Publishing Ltd

Opening the internal structure for transport of ions: Improvement of the structural and chemical properties of single-walled carbon nanohorns for supercapacitor electrodes

We investigated the electrochemical performance of single-walled carbon nanohorns (SWCNHs) for use as supercapacitor electrodes. For the first time, we used acid-treatment for oxidation of SWCNHs and hole creation in their structure. A detailed study was performed on the correlation between the oxidation of SWCNHs via acid treatment and variable acid treatment times, the structural properties of the oxidized carbon nanostructures, and the specific capacitance of the SWCNH electrodes. We showed that simple functionalization of carbon nanostructures under controlled conditions leads to an almost 3-fold increase in their specific capacitance (from 65 to 180 F g−1 in 0.1 M H2SO4). This phenomenon indicates higher accessibility of the surface area of the electrodes by electrolyte ions as a result of gradual opening of the SWCNH internal channels

Introducing a novel nanocomposite consisting of nitrogen-doped carbon nano-onions and gold nanoparticles for the electrochemical sensor to measure acetaminophen

In the present study, gold nanoparticles and nitrogen-doped carbon nano-onions (AuNP/NCNO) in a nanocomposite-based sensor were reported for the electrochemical detection of acetaminophen (APAP). The NCNOs from the fullerene family were prepared using a simple and cost-effective method using aminated nanodiamonds (AM-ND) as a substrate. Nitrogen atoms were introduced into CNO cages during the preparation of these nanostructures by annealing AM-NDs under an inert helium atmosphere and reduced pressure. AuNPs were synthesized using a straightforward method. The nanocomposite profoundly enhanced the active surface area of the glassy carbon electrode and amplified the electron transfer rate. Accordingly, electrocatalysis of the APAP was achieved at the modified electrode surface at 0.38 V vs. Ag/AgCl. Under the optimal conditions, the sensor displayed a linear response for APAP detection ranging from 25 nM to 35 μM with a limit of detection (LOD) of 9 nM. Potentially interfering drugs, such as ascorbic acid and dopamine, with 5-fold higher concentrations did not interfere with APAP detection. The feasibility of the sensor for APAP detection in tablet and serum samples was successfully evaluated. The qualities of this sensor, including its rapid-response, sensitivity and ease of use, maybe beneficial for potential applications in detecting other drugs. © 202

Triple helical collagen like peptide interactions with selected polyphenolic compounds

Because collagen is the most abundant component of connective tissue, it is an excellent biomaterial in numerous medical applications.</p

Linking the defective structure of Boron-Doped Carbon Nano-Onions with their catalytic properties: Experimental and theoretical studies

Defects are widely present in nanomaterials, and they are recognized as the active sites that tune surface properties in the local region for catalysis. Recently, the theory linking defect structures and catalytic properties of nanocatalysts has been most commonly described. In this study, we prepared boron-doped carbon nano-onions (B-CNOs) by applying an annealing treatment of ultradispersed nanodiamond particles and amorphous boron. These experimental conditions guarantee doping of CNOs with boron atoms in the entire carbon nanostructure, thereby ensuring structural homogeneity. In our research, we discuss the correlations between defective structures of B-CNOs with their catalytic properties toward SO2 and tert-butanol dehydration. We show that there is a close relationship between the catalytic properties of the B-CNOs and the experimental conditions for their formation. It is not only the mass of the substrates used for the formation of B-CNOs that is crucial, that is, the mass ratio of NDs to amorphous B, but also the process, including temperature and gas atmosphere. As it was expected, all B-CNOs demonstrated significant catalytic activity in HSO3– oxidation. However, the subsequent annealing in an air atmosphere diminished their catalytic activity. Unfortunately, no direct relationship between the catalytic activity and the presence of heteroatoms on the B-CNO surface was observed. There was a linear dependence between catalytic activity and Raman reactivity factors for each of the B-CNO materials. In contrast to SO2 oxidation, the B-CNO-a samples showed higher catalytic activity in tert-butanol dehydration due to the presence of Brønsted and Lewis acid sites. The occurence of three types of boron-Lewis sites differing in electron donor properties was confirmed using quantitative infrared spectroscopic measurements of pyridine adsorption