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.com
Volume 7
Biosensors Journal
ISSN: 2090-4967
Electrochemistry 2018
June 11-12, 2018
June 11-12, 2018 | Rome, Italy
4
th
International Conference on
Electrochemistry
Computational modeling and studies of hydroxyapatite with defects of the oxygen vacancy type
providing its photocatalytic activity
Vladimir S Bystrov
1
, Jose Coutinho
2
, Leon A Avakyan
3
, Anna V Bystrova
1
, Ekaterina V Paramonova
1
and
Yuri D Dekhtyar
4
1
Keldysh Institute of Applied Mathematics RAS, Russia
2
University of Aveiro, Portugal
3
Southern Federal University, Russia
4
Riga Technical University, Latvia
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.
Recent Publications:
1. Bystrov V S, Coutinho J, Bystrova A V, Dekhtyar Y D, Pullar R C, Poronin A, Palcevskis E, Dindune A, Alkan B, Durucan
C and Paramonova E V (2015) Computational study of hydroxyapatite structures, properties and defects. J. Phys. D:
Appl. Phys. 48:195302.
2. Bystrova A V, Dekhtyar Yu D, Popov A I, Coutinho J and Bystrov V S (2015) Modified hydroxyapatite structure and
properties: modeling and synchrotron data analysis of modified hydroxyapatite structure. Ferroelectrics 475(1):135-147.
3. V S Bystrov, C Piccirillo, D M Tobaldi, P M L Castro, J Coutinho, S Kopyl and R C Pullar (2016) Oxygen vacancies, the
optical band gap (Eg) and photocatalysis of hydroxyapatite: comparing modelling with measured data. Applied Catalysis
B: Environmental. V 196:100–107.
4. V Bystrov, A Bystrova and Yu Dekhtyar (2017) HAP nanoparticle and substrate surface electrical potential towards bone
cells adhesion: Recent results review. Advances in Colloid and Interface Science 249:213-219.
5. V S Bystrov et al. (2017) Surface modified hydroxyapatites with various functionalized nanostructures: computational
studies of the vacancies in HAP. Ferroelectrics 509:105–112.
Biography
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.
vsbys@mail.ruVladimir S Bystrov et al., Biosens J 2018, Volume 7
DOI: 10.4172/2090-4967-C1-003