Search

Mycotoxins are widespread chemical entities in the agriculture and food industries that can induce cancer growth and immune deficiency, posing a serious health threat for humankind. These hazardous compounds are produced naturally by various molds (fungi) that contaminate different food products and can be detected in cereals, nuts, spices, and other food products. However, their detection, especially at minimally harmful concentrations, remains a serious analytical challenge. This research shows that high-performing plasmonic substrates (analytical enhancement factor = 5 × 10 7 ) based on plasma-grown vertical hollow carbon nanotubes can be applied for immediate detection of the most toxic mycotoxins. Due to excellent sensitivity allowing operation at ppb concentrations, it is possible to collect vibrational fingerprints of aflatoxin B 1 , zearalenone, alternariol, and fumonisin B 1 , highlighting the key spectral differences between them using principal component analysis. Regarding time-consuming conventional methods, including thin-layer chromatography, gas chromatography, high-performance liquid chromatography, and enzyme-linked immunosorbent assay, the designed surface-enhanced Raman spectroscopy substrates provide a clear roadmap to reducing the detection time-scale of mycotoxins down to seconds., (© 2021 Wiley-VCH GmbH.)

Energy deficiency, global poverty, chronic hunger, chronic diseases, and environment conservation are among the major problems threatening the whole mankind. Nanostructure-based technologies could be a possible solution. Such techniques are now used for the production of many vitally important products including cultured and fermented food, antibiotics, various medicines, and biofuels. On the other hand, the nanostructure-based technologies still demonstrate low efficiency and controllability, and thus still are not capable to decisively address the global problems. Furthermore, future technologies should ensure lowest possible environmental impact by implementing green production principles. One of the most promising approaches to address these challenges are the sophisticatedly engineered biointerfaces. Here, the authors briefly evaluate the potential of the plasma-based techniques for the fabrication of complex biointerfaces. The authors consider mainly the atmospheric and inductively coupled plasma environments and show several examples of the artificial plasma-created biointerfaces, which can be used for the biotechnological and medical processes, as well as for the drug delivery devices, fluidised bed bioreactors, catalytic reactors, and others. A special attention is paid to the plasma-based treatment and processing of the biointerfaces formed by arrays of carbon nanotubes and graphene flakes.

Highly controllable fabrication of the nanowire, nanocone, and mixed nanowire/nanowall arrays of iron oxide (hematite, α-Fe2O3) nanostructures in a simple, environment-friendly process is achieved by exposing the metal foils to low-temperature oxygen plasmas. Very dense forests of thin (≈50 nm) and long (up to several μm) nanowires are grown on the electrically biased substrates, whereas the use of the electrically insulated substrate resulted in the formation of a mixed array of nanowires and nanowalls. The proposed mechanism of the nanostructure growth is supported by the numerical simulations demonstrating the key role of the plasma environment in the growth morphology selection. [ABSTRACT FROM AUTHOR]

The possibility to control the morphology and nucleation density of quasi-one-dimensional, single-crystalline α-Fe2O3 nanostructures by varying the electric potential of iron surfaces exposed to reactive oxygen plasmas is demonstrated experimentally. A systematic increase in the oxygen ion flux through rf biasing of otherwise floating substrates and then an additional increase of the ion/neutral density resulted in remarkable structural transformations of straight nanoneedles into nanowires with controlled tapering/aspect ratio and also in larger nucleation densities. Multiscale numerical simulations relate the microscopic ion flux topographies to the nanostructure nucleation and morphological evolution. This approach is applicable to other metal-oxide nanostructures. [ABSTRACT FROM AUTHOR]

• Novel plasma-based approach to design hybrid N-Graphene-metal-based nanostructures is created. • The synthesis method is controllable, single-step and at atmospheric conditions. • Metal oxide/sulfide anchored N-graphene at large scale (~19 mg/min) are produced. • Electrode for supercapacitor with metal oxide/sulfide-N-graphene was developed. • The electrode demonstrated promising specific capacitances ∼ 273 F.g−1 at 0.5 A.g−1. Hybrid graphene-based nanostructures are considered promising materials for energy storage applications. However, the synthesis of high-quality hybrid graphene nanostructures at high yields is challenging. In the present work we propose a novel, single-step microwave plasma-enabled approach to synthetize customizable hybrid graphene-based nanostructures at high-yield while preserving their quality. Hybrid N-graphene (nitrogen-doped graphene) metal-based nanostructures, for instance, can be produced at a rate of ∼ 19 mg/min. The high energy density region of a microwave plasma provides sufficient energy and "building particles" fluxes towards the low-energy density plasma afterglow for the processes of assembly and growth of N-graphene sheets. Simultaneously, a controlled jet of metal-oxide(-sulfide) microparticles is sprayed into the plasma afterglow region where they bind to N-graphene sheets. Methane/methylamine are used as carbon and nitrogen precursors, combined with micron-sized MnO 2 and oxy-MnS particles to synthesize the hybrid structures. As a result, nano-sized (∼10–30 nm) MnO x particles decorated N-graphene (4.6 at. N%) and oxidized metal sulfide anchored N-graphene sheets (3.1 at. N%) are produced at atmospheric conditions. High structural quality and distribution of metal-based nanostructures on N-graphene sheets are revealed using transmission and scanning electron microscopes and other advanced spectroscopic techniques. Finally, an electrode for supercapacitor based on the N-graphene-metal-oxide(sulfide) hybrid nanostructures is developed with promising specific capacitances (∼273 F.g−1 at 0.5 A.g−1). The described chemically engineered process is one of the fastest approaches reported for designing the high-quality hybrid nanostructures produced at a high-yield, and as such, is expected to provide a high impact on the design of electrode materials for sustainable energy storage systems. [ABSTRACT FROM AUTHOR]

[Display omitted] • Versatile one step synthesis of TiO 2 /WO 3− x hybrid nanowire beams. • Mechanism of formation of the nanowire beams in ethanoic acid. • Conversion of TiO 2 -based nanomaterials from nanoparticles to nanowire beams. • Modifying photoluminescence properties of TiO 2 nanomaterials by WO 3− x. In this paper, we report the one-step synthesis of the TiO 2 /WO 3− x hybrid nanomaterials in ethanoic acid using the tungsten hexachloride (WCl 6) and titanium butoxide precursors. The characterization results indicate that the WO 3− x incorporation in TiO 2 nanomaterials leads to the morphology conversion of TiO 2 nanomaterials from the nanoparticles to the nanowire beams. The conversion mechanism is based on enhancing the nucleation rate of TiO 2 and the viscosity of the solution containing the mixed WCl 6 powder and titanium butoxide precursors. The photoluminescence (PL) studies reveal that the as-synthesized TiO 2 /WO 3− x hybrid nanomaterials generate the UV, blue, green and red light, and these emissions are related to the band-band transition, surface states, oxygen vacancies and the transition between the gap state and valence band, respectively. Furthermore, WO 3− x also leads to the PL quenching due to the oxygen vacancy migration and charge transfer across the TiO 2 /WO 3− x interfaces and the enhancement of nonradiative recombination centers. Finally, the application of the as-synthesized hybrid nanomaterials in the area of photocatalysis was explored. [ABSTRACT FROM AUTHOR]

• One-step, versatile-synthesis of WO x /ZnWO 4 hybrid nanostructres. • Mechanism of formation of WO x /ZnWO 4 hybrid nanostructres by annealing in vapor. • Controlled formation of WO x hybrid nanostructures with tunable photoluminescence. • Modifying photoluminescence properties of WO x nanomaterials by ZnWO 4. Substoichiometric tungsten oxide (WO x , 2 < x < 3) nanomaterials are important nanoscale semiconductor materials with broad applications in optoelectronic devices; however a controllable modification of their physical properties remains challenging task. Here, we report an alternative green synthesis of hybrid nanostructures composed by WO x and ZnWO 4 phases in ethanol via a solvothermal process using ZnO and WCl 6 as the precursors. The results indicate that the formation of ZnWO 4 leads to the structural conversion of WO x from nanorods to nanoparticles due to the effect of ZnWO 4 on the side growth of WO x nanostructures. Moreover, the surface morphology tailored by ZnWO 4 and crystalline phase transformation induce different photoluminescence (PL) emission from pure WO x nanostructures and WO x /ZnWO 4 hybrid nanostructures due to the increased number of oxygen vacancies. [ABSTRACT FROM AUTHOR]