Dr. Vasileios Tzitzios graduated from the Aristotle University in Thessaloniki (Greece), where he received his B.Sc. degree in Chemistry in 1995 and M.Sc. in Chemical Technology in 1998, concluding his studies by gaining Ph.D. in Chemistry from the Department of Chemistry in 2003. Since May 2003 he has worked as a research associate at the Institute of Material Science of the National Center of Scientific Research “Demokritos” (Athens, Greece), while also a visiting researcher in the Department of Physics and Astronomy of the University of Delaware in the USA, in the Condensed Matter and Physics Department at the Jozef Stefan Institute in Ljubljana Slovenia and at the Khalifa University of Science and Technology, Petroleum Institute in Abu Dhabi in the Chemical Engineering Department. Since July 2019 he holds a Researcher position (Grade C), in the Institute of Nanoscience and Nanotechnology, NCSR Demokritos. Over his career he has workied in the field of materials chemistry and nanochemistry, combining advanced inorganic chemistry with materials science and nanotechnology.
Dr. Tzitzios research interests covers two general aspects:
(1) Chemical synthesis and self-assembly of NPs;
(2) Development of functional/hybrid nanostructured materials for applications in a) Magnetism b) Catalysis, c) Biomedicine and d) Energy, through internal and international collaboration.
Synthesis and self-assembly:
His research work focuses using a “bottom-up” approach to synthesize monodisperse nanoparticles (NPs) and inorganic/organic composite materials following polyol, thermolytic and organometallic approaches. By controlling the reaction conditions the atoms “stack” in certain dimensions and directions leading to the formation of nanoparticles with desirable sizes and shapes. Currently he is working on exploring multi-component alloy, core/shell and dumbbell-like NPs stabilized by a lipid-type molecule (surfactant) and are readily dispersed in specific solvents. The stable dispersion allows self-assembly on a solid support via solvent evaporation. These NPs can be tuned to have specific physical and chemical properties for nano-technological applications.
Magnetic Nanomaterials: His research focuses on the chemical synthesis of bimetallic L10 structured colloids (such as FePt, CoPt) providing important insights in the direct synthesis of the hard magnetic phase directly in the liquid phase reaction avoiding post annealing procedures. The research also investigates exchange-coupled “hard” and “soft” phase nanocomposites which show enhanced ferromagnetism and may serve as materials for building super-strong magnets. In addition he is involved in the development, via liquid phase chemical reactions, of Fe, Co and Ni based novel rare-earth free magnetic materials with high magnetocrystalline anisotropy such as L10 FeCo and L10 FeNi.
Nanoparticles for Biomedical Applications: With the dimension controls achieved with “bottom-up” synthesis, magnetic NPs can be made ferromagnetic or superparamagnetic. Superparamagnetic iron oxide NPs, are especially important for biological applications as they have no net magnetization at the biologically relevant temperature and therefore no strong dipolar interactions, which facilitate their long-term stabilization. However, they can be magnetized under an external magnetic field, reaching ferromagnet-like magnetizations. My current research, focuses on the synthesis of superparamagnetic Fe3O4 and γ-Fe2O3 nanoparticles, and their hybridization with Au or Bi2S3 nanoparticles via novel physicochemical approaches for the synthesis of multifunctional “nanoparticles clusters”. These hybrid nano-objects in the sub 100 nm diameter size range, are studied as multi-imaging contrast agents (MRI, PET, CT) in combination with magnetic hyperthermia.
Novel soft matter/NPs composites: The coupling of Liquid Crystal (LC) science and technology with nanotechnology is creating a promising new field aiming at the discovery of novel soft materials characterized by enhanced organizational complexity at the molecular level and extraordinary potential for technological advancements in the display and sensor industry. This research addresses the lack of fundamental knowledge of the properties and phase behavior of hybrid materials consisting of LCs and nanoparticles (such as Quantum Dots and 2D materials). The project was recently funded by the THALES Project “Nanoparticles dispersed in liquid crystalline media: Organization and complexity in novel soft matter system” and John S. Latsis Public Benefit Foundation (2012).
Nanoparticles for Catalytic Applications: With the decrease in NP size, a large fraction of atoms become exposed. More importantly, NPs in this nanoscale have large fraction of crystal facets, edge- and corner-sites that may dominate the interaction between NP surface and molecules and show greatly enhanced catalysis such as in CO2 reduction electrocatalysis and O2 reduction reactions. Therefore, the control of NP size, shape, composition are essential for tuning NP electronic and geometric structures for catalytic applications. At present, work is focussed on developing efficient hydrotreatment catalysts based on transition metal phosphides, nano-zeolites (FAU type) for the fluid catalytic cracking process (US patent have been applied), nano-MOF for sorption applications, MPt/r-GO nanocomposites for electrochemical reduction reactions, transition metal doped CeO2 for low temperature CO oxidation, and noble metal nanoparticles for low temperature SO2 hydrogenation.
He is a Review Editor for Carbon-Based Materials in Frontiers in Materials (Loop | Vasileios Tzitzios (frontiersin.org)) and guest Editor in Nanomaterials (Nanomaterials | Special Issue: Synthesis, Development and Characterization of Magnetic Nanomaterials (mdpi.com)).