4^th International Conference on Electrochemistry June 11-12, 2018 Rome, Italy

Vladimir S Bystrov has completed PhD, Dr. Habil.Phys. Dr.Sci. Phys. & Math. from Russian Academy of Sciences. Since 1993, he has his expertise in various fields of computational molecular modeling, computational exploration and computer simulation of nonlinear multifunctional nanomaterials and different organic & bio-molecular nano-structures such as: bioferroelectric & polymer PVDF/PVDF-TrFE thin ferroelectric films, graphene/oxide graphene and related polar composite nanomaterials; amino acids (glycine, etc.), peptides nanotubes, thymine & DNA; hydroxyapatite (HAP) & nanoparticles, etc. Computational studies of nanostructures were made using the molecular mechanics, quantum-chemical calculations (ab initio, DFT, semi-empirical methods), molecular dynamics (MD) on the base of various software (HyperChem, AIMPRO, VASP, etc.) and clusters in Russia IMPB & KIAM, Linux cluster in University of Aveiro, Portugal. He is a Head of the Group for Computer Modelling of Nanostructures and Biosystems of IMPB-KIAM RAS, Pushchino.

A new model of the structure of hydroxyapatite (HAP) with defects of the oxygen vacancy type and hydroxyl group vacancy type has been developed. The model made it possible to explain the change in the optical properties of the HAP and provide for the mechanism of its photocatalytic activity. The obtained new results and knowledge allow us to already purposefully change the optical properties of HAP (introduction of the necessary type of the defects) and control the photocatalytic activity of HAP, which is extremely important for many practical applications (in the cleaning the environment, including the water from harmful impurities and components, in the chemical photocatalytic synthesis, in the antimicrobial treatment, etc.). The model is developed on the basis of several new approaches to the density functional theory (DFT) with combined application of the various hybrid and exchange-correlation functionals, and also taking into account the Coulomb shielding of the defect charge, which allows made more exact and accurate calculation of structural, optical and other properties of HAP materials. These approaches continue to develop on some new more complex models of the super-cells of HAP, which will allow us to obtain a number of even more highly accurate results of calculations of the HAP properties for both pure and with different defects. The computed properties of HAP material with super-cell model (2x2x2 - 8 unit cell) are considered using semi-local (PBE potential) and hybrid exchange-correlation functionals with different fraction of exact exchange contribution. The excitation properties are compared with the results of GW-approximation method for calculation of quasi-particle band structure. It was shown that optical properties of bulk HAP are best described using B3LYP exchange-correlation functional and for pure HAP have band gap Eg ~ 7.3 eV, while with O vacancy it is lowered.

Michał Stępień graduated MSc from the AGH University of Science and Technology in 2010. He received his PhD degree in 2015 (Synthesis of oxides nanostructures on the surface of selected transition metals) under the guidance of Professor Krzysztof Fitzner. His research interests are based on synthesis and surface modification oxides nanotubes. Now he is a Research Worker in AGH in Department of Physical Chemistry and Metallurgy of Non-Ferrous Metals.

Depending on the thickness of the oxide layer on niobium different properties of this material can be obtained, which can be exploited in sensing, decorative materials, electronic paper and displays. The aim of this work is to produce the oxide layer in the controlled way utilizing electrochemical experiment. The layer of the oxide will be formed by anodization of Nb electrode in acidic aqueous solution. Then, the electrochemical impedance spectrometry (EIS) is used to control the thickness of the growing layer due to the relation: where: ε0 – permittivity of the vacuum; εr – permittivity of the oxide film; A – geometric area of the oxide; d – barrier oxide thickness; C – capacitance obtained from EIS after proper choice of the equivalent circuit. However, successful control requires exact knowledge of dielectric constant of niobium oxide. Depending on oxidation conditions, different values of εr can be obtained. Therefore, this value will be verified by using simultaneously EIS and ellipsometric measurements.

Anna A Murashkina has her expertise in the development and investigation of semiconductors for the solar energy conversion into the chemical energy. These semiconductor materials can be used in photocatalytic systems for water and air purification, formation of self-cleaning and antibacterial coatings, in solar cells and sensors.

Titanium dioxide is the most extensively studied photoactive material since the discovery of water photo-assisted electrolysis with titanium dioxide photo-anode. Materials based on titanium dioxide can be used in photocatalytic systems for water and air purification, formation of self-cleaning and antibacterial coatings, in solar cells and sensors. Titanium dioxide possesses a sufficiently high photochemical (photocatalytic) activity, good chemical stability and non-toxicity and low cost of its production. In the present study we explored the effect of Al dopant concentration within the range <1.1 wt.% on the photoelectrochemical activity of Al doped TiO2 photo-anode. The experimental dependencies of photoelectrochemical efficiency on Al dopant concentration indicate that there is an optimal Al concentration 0.5 wt.% corresponding to the highest photo-activity. The analysis of the spectral dependencies of the photocurrent confirms that 0.5 wt.% of Al provides the highest activity at photoexcitation in both intrinsic and extrinsic absorption spectral range. It was also shown that Al doping does not affect the optical band gap of TiO2. The dependence of photoelectrochemical activity on Al concentration correlates with the corresponding dependencies of the flat band potential and work function indicating the shift of the Fermi level toward the conduction band for the Al concentration <0.5 wt.% and toward the valence band for the Al concentration >0.5 wt.%. Such alteration of the Fermi level position is explained in terms of alteration of the type of major compensating intrinsic defects for Al concentration <0.5 wt.% acting as shallow traps, to Al concentration >0.5 wt.% acting as deep traps. Transformation of compensating defects from shallow traps which are ineffective in charge recombination processes to deep traps which act as effective recombination centers is responsible for the optimal dopant concentration, 0.5 wt.%, to achieve the higher photoelectrochemical activity of Al-doped TiO2.

Rajatava Mukhopadhyay has pursuing in Jagadis Bose National Science Talent Search, India

Electricity and magnetism were considered as separate identities until late 19th century, when people like Maxwell, Faraday came to the forefront to change the idea. Classical electromagnetic theory of Maxwell, with the help of certain experiments, disclosed that current electricity and magnetism at two opposite faces of the same coin, that is, they are different approaches to the same aspect of physics. Electromagnetism is one of the most important aspects of physics, since it broke the jinx of classical physics and paved the way to the beginning of research about structure of matter and consequently to the foundation of quantum mechanics. An electric current can induce a magnetic field, and vice-versa. So, electricity and magnetism should, so to say, be interchangeable, which is the main idea we have tried to implement. Electrolysis is something we are all familiar with. In electrolysis, electricity flows due to a potential difference developed across the two electrodes of a cell, due to differential reduction potential at the two terminals. So, can this potential difference be induced using a magnet too? Surprisingly, yes. Replacing the cathode and anode of an electrolytic cell with the north and south poles of a magnet (respectively), we get the exact same result as that expected from electrolysis. Cations get attracted to the north and anions to the south pole. Electrons flow from the south to the north pole through the magnet (analogous to anodeàexternal circuitàcathode) and current from the north to the south, on completing the circuit (for a half-cell setup). Morever, a magnetolytic cell can be recharged be simply reversing the polarity of the two half-cells, by exchanging the magnetic poles immersed in them. So, to conclude, lysis and current flow with the help of magnets ---- ‘magnetolysis’, maybe a viable, sustainable and economic alternative to electrolysis in the near future. All practical applications of an electrolytic cell can be realised through an analogous magnetolytic cell. All the experimental data, associated graphs and data are stored for future reference.