Anastasiia V. Shabalina

Metal Oxide Nanoparticle Preparation by Pulsed Laser Ablation of Metallic Targets in Liquid

The basic mechanisms of pulsed laser ablation in liquids (PLAL) as a method for the synthesis of nanoparticles (NPs) were considered. Physical and chemical processes occurring during the PLAL that determine the formation, composition and structure of the nanoparticles obtained are described. The influence of the composition and properties of the target material, the solvent and the characteristics of the laser irradiation on the efficiency of the synthesis of nanoparticles is discussed. Separately, an influence of the absorption and scattering (including nonlinear) of laser radiation in the dispersion of nanoparticles on the primary synthetic processes and secondary transformations inside the colloidal solution is examined. The specificity of the characterization of the colloidal solutions of oxide particles produced by PLAL is highlighted. The most promising practical applications of nanomaterials obtained are identified and the examples of their successful use in catalytic research and biomedicine are provided.

Cu2O Water Dispersions and Nano-Cu2O/Fabric Composite: Preparation by Pulsed Laser Ablation, Characterization and Antibacterial Properties

Colloidal solutions of copper (I) oxide, Cu2O, were obtained by pulsed laser ablation of metallic copper target in distilled water using fundamental harmonic of Nd:YAG laser (1064 nm, 7 ns, 20 Hz). Nanocolloids obtained were applied to cotton fabric. Nanoparticles composition and structure were studied by UV-Vis and Raman spectroscopy, transmission and scanning electron microscopy, and XRD. Antibacterial activity of Cu2O nanoparticles on cotton fabric to E.coli bacteria was demonstrated in comparison with zinc oxide nanoparticles.

Synthesis and Characterization of CeO2 Nanoparticles

Dispersions of cerium oxide nanoparticles in water, ethanol, and water-ethanol solution were synthesized for the first time using laser ablation of metallic target. The fundamental harmonic of nanosecond Nd:YAG laser was used. Nanocrystalline powders of cerium oxide were obtained from the dispersions. The average size of the crystallites was 17-19 nm. Phase composition of nanoparticles was confirmed by X-ray diffraction and Raman spectroscopy. It was found that carbon present on the surface of CeO2 particles. The materials obtained may be used as catalyst carriers for CO oxidation, and as active components of sunscreen cosmetic products.

Electrode modified by copper nanoparticles for ascorbic acid and dopamine simultaneous determination

In the present work it is proposed to modify a glassy carbon electrode by copper nanoparticles obtained by the laser ablation method. This modified electrode makes it possible to obtain separate peaks of ascorbic acid and dopamine electro-oxidation with their simultaneous presence. It is proposed that this effect should be utilized to determine these compounds via voltammetry.

Visualization of nanoconstructions with DNA-Aptamers for targeted molecules binding on the surface of screen-printed electrodes

Nanoconstructions of gold nanoparticles (NPs) obtained via pulsed laser ablation in liquid with DNA-aptamer specific to protein tumor marker were visualized on the surface of screen-printed electrode using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). AuNPs/aptamer nanoconstuctions distribution on the solid surface was studied. More uniform coverage of the carbon electrode surface with the nanoconstuctions was showed in comparison with DNA-aptamer alone on the golden electrode surface. Targeted binding of the tumor marker molecules with the AuNPs/DNA-aptamer nanoconstuctions was approved.

Copper Nanoparticles for Ascorbic Acid Sensing in Water on Carbon Screen-printed Electrodes

A carbon screen-printed electrode was modified with copper nanoparticles from their dispersion obtained via pulsed laser ablation of a copper target in ethanol. The modified electrode exhibited activity in ascorbic acid electrochemical oxidation, giving an anodic current peak on voltammograms. Linear sweep and cyclic voltammetry have shown a linear dependence of the signal (both peak height and peak area) on the ascorbic acid concentration. The linear range from 1 to 250 μM of ascorbic acid was studied, and the detection limit was experimentally found to be 0.5 μM. The amperometric response to the addition of ascorbic acid portions into the solution was recorded. For the case of the simultaneous presence of ascorbic acid and glucose, two separate signal were obtained. Thus, the modified electrodes are characterized by the following advantages: disposable use; small amount of the samples required for the analysis; lower price (cheap copper is used); simple and easy modification procedure; good metrological characteristics; selectivity.

F-Doped Titanium Dioxide Modified by Copper Preparation and Characterization

This work is dedicated to preparation and research of copper-containing solid-state mixed oxides based on F-doped titanium dioxide. All materials were prepared by hydrolysis of titanium tetraisopropoxide. NH4F was used as F‑ions source. Copper was introduced to the system in two ways: by impregnation from its copper nitrate and directly in the process of titanium dioxide synthesis. Microstructure, phase composition and surface area were studied by transmission electron microscope (TEM), X-ray diffraction (XRD) and low temperature nitrogen adsorption respectively. All materials have nanostructured porous structure and the majority of them contain only one TiO2 phase – anatase. States of the elements were determined by X-ray photoelectron spectroscopy (XPS). Photoluminescence spectra (PL) show low intensity of photoluminescence for TiO2 and F-TiO2 samples and no photoluminescence for copper-containing samples. The absence of photoluminescence for copper-containing samples is associated with efficient charge transfer and separation.

Pure Metal Nanoparticles for Selective Electrochemical Sensor of Organic Substances

The field of application of electrochemical analysis has been significantly widened after modified electrodes appeared. Metallic nanoparticles are ones of the most common used modifiers of the electrode surface to increase the sensitivity and selectivity of the analysis. Increasing of selectivity is extremely important in cases when two or more analyts have electro-chemical signals at nearly the same values of electrode potential. Dopamine and ascorbic acid are an example of such case. In present work Au, Pt, Pd, and Ni “pure” nanoparticles obtained by laser ablation without stabilizing agents were used to modify the surface of a glassy carbon electrode. Modified electrodes were tested in solutions of ascorbic acid and dopamine at their simultaneous electro-oxidation. It was shown that Au, Pt, and Ni nanoparticles on the electrode surface increase the selectivity of analysis giving two separate peaks of analyts.

Carbon electrodes modified by metal nanoparticles obtained by laser ablation method in organic substances determination

Impregnated graphite electrodes surface modification by metal nanoparticles (Au, Pt, Pd, Ni, Cu) from ethanol colloids obtained by laser ablation of metal targets in liquid without stabilizing agents was carried out. Electrochemical behavior of modified electrodes was explored using voltammetry. The possibility of its utilization in organic compounds analysis was evaluated using the example of the common analytes: ascorbic acid, dopamine, adrenaline, glucose and hydroquinone.

Highly porous cellular copper as a catalyst for ozone oxidation of organic water pollutants

The synthesis of high-porosity cellular copper and structural features of its surface were studied. Results obtained in studying the activity of high-porosity copper catalyst during ozone oxidation of organic substances dissolved in water are given by an example of oxalic and benzoic acids.