Chemical Synthesis of Multi-Functional Nanomaterials
Materials and Nano Chemistry
Nano/materials chemistry research focuses on nanoparticles’ synthesis and characterization of magnetic materials, nanoclusters, quantum dots, organic/inorganic hybrid materials (liquid crystals/inorganic particles hybrids), 2D materials, and porous materials (zeolites and MOF), for applications in permanent magnetism, nanomedicine and medical imaging, catalysis, energy, environment, and self-assembly.
Nanoparticle Synthesis and self-assembly
Our research work focuses on the utilization of the so called “bottom-up” approach to synthesize monodisperse Nanoparticles (NPs) following polyol, thermolytic and organometallic approaches. By appropriate control of the solutions’ reaction conditions, the atoms can be “stacked” in certain dimensions and directions leading to the formation of nanoparticles with desired sizes and shapes. These NPs are stabilized by a lipid-type molecule (surfactant) and are readily dispersed in a specific solvents. The stable dispersion allows self-assembly of these NPs via solvent evaporation.
Hard Magnetic Materials
Our research focuses on the chemical synthesis of bimetallic L10 structured colloids (such as FePt, CoPt) providing important insights into the direct synthesis of the hard magnetic phase through liquid phase reactions, avoiding the need for post-annealing procedures.
This research area also covers nanocomposites containing exchange-coupled nanoscale “hard” and “soft” phases which show greatly enhanced ferromagnetism and may serve as ideal materials for creating new super-strong magnets.
Nanoparticles for Biomedical Applications:
The current research focuses on the synthesis of superparamagnetic Fe3O4 and γ-Fe2O3 nanoparticles, and their composites with Au, Bi2S3 nanoparticles or other diamagnetic materials via novel physicochemical approaches for the creation of individual and multifunctional “nanoparticles clusters”. These hybrid nano-objects in the sub-100 nm diameter size range are under study as multi-imaging (MRI, PET, CT) contrast and magnetic hyperthermia agents.
Novel hard/soft matter composites:
The coupling of Liquid Crystal (LC) science and technology with nanotechnology is creating a promising new field aimed at the discovery of novel soft materials characterized by enhanced organizational complexity at the molecular level. These materials have extraordinary potential for technological advancements in the display and sensor industry. The project addresses the lack of fundamental knowledge of the properties and phase behavior of hybrid materials consisting of LCs and NPs (such as Quantum Dots and 2D materials).
Nanoparticles for Catalytic, Environmental and Energy Applications:
With decreasing NP size, a greater fraction of the NP atoms become exposed at the NP surface. Consequently, NPs have a large fraction of crystal facets, edge- and corner-sites that strongly influence the interaction between NP surface and molecules and lead to enhanced catalysis useful for electrocatalytic CO2 reduction and O2 reduction reactions. Thus, control of NP size, shape, composition are essential for the tuning of NP electronic and geometric structures for catalytic applications. We are developing efficient hydrotreating catalysts based on transition metal phosphides, nano-zeolites (FAU type) for the fluid catalytic cracking process, 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.
In addition, magnetic composites are studied for heavy metal ion removal water purification. Finally, transition metal sulfides and sulfur derivatives and composites are also studied for applications in batteries.
Our research on nano/materials chemistry focuses on nanoparticles synthesis via bottom-up liquid phase approaches utilizing simple inorganic metal salts in combination with appropriate capping molecules (amines, phosphines, carboxylic acids etc.), and reducing agents in water or organic solvent environment. Controlling the basic reaction parameters particles size and shape successfully manipulated in 1, 2 and 3D, in a plethora of materials including magnetic alloys, quantum dots, metal oxides, sulfides and phosphides, organic/inorganic hybrids, zeolites and MOF with applications in permanent magnets, catalysis, biomedicine, energy storage, and self-assembly. Our research taking place in collaboration with many other national and international groups.
Among the first priorities for the forthcoming 4-years period are the establishing of strategic national and international collaborations for the most efficient resources attraction form both government and private sectors as well as the expansion of nanomaterials applications in diverse fields. At the same time one major target is the group growth with the integration of post-doctoral and PhD candidates.
Concerning the main research directions and objectives include the development of state of the art and beyond nanomaterials with application that covers the areas of magnetism, biomedicine, catalysis, energy and environment.
In particular concerning the area of magnetic materials and nanomagnetism the development of less Pt L10 ordered bimetallic nanoalloys, such as FePt and CoPt, as well as the synthesis of rare-earth and precious metals free nanoalloys based on Fe, Ni and Co, materials with high magnetocrystalline anisotropy is among the major scientific targets. Furthermore, the future plans include the development 2D magnetic materials, which due to their strong in-plane exchange interactions could be enable to the control of the spins and their interactions, and stabilize magnetic states close or even at room temperature, generating a new thrust in the field of information storage and spintronic applications. Towards biomedical applications our research topics include the synthesis of non-toxic iron based nano-platforms for both MRI and magnetic hyperthermia in close collaboration with Mount Sinai Hospital and Medical school, NY (Prof. Costas Hadjipanayis). The major target is the development of ferromagnetic nano-architectures in order to supress the interparticle interactions, and maximizing their contrast agent and hyperthermia ability. An additional target also include the formation of multi-imaging contrast agents (MRI, PET, CT).
In the field of catalysis and environment through close collaboration with Prof. Veronica Sofianos (UCD, Ireland), Prof. George Tsilomelekis (Rutgers University) our research objectives include studies of the magnetically hard, L10 ordered nanoalloys in the field of electrocatalytic hydrogen production via HER and the application of Fe based ferromagnetic materials in the removal of pollutant from drinking water via selective absorption and magnetic separation. Also our activities in the current field include the development of single atom catalysts focused on the noble and precious metals single atom growth on sustainable oxides matrices such as Fe2O3, TiO2 and CeO2.
In the field of energy storage we are focusing on the elemental sulfur utilization, a well-known oil industry waste materials, for the synthesis of a variety of transition metal sulphides including Chalcopyrite, Fe-Ni binary, and other ternary and multi-metallic sulphides, as well as sulfur/carbon composites including S/Graphene. Additionally, the 2D structuring of Sulfur and S/Se hybrids is among our very ambitious research objectives concerning the development of novel liquid phase methodologies for the formation of 2D materials from non-van der Waals 2D ones. All the above will be extensively studied in collaboration with Prof. Aristidis Bakandritsos (Palacky University of Olomouc in Czech Republic), as energy storage materials including Na-ions battery and supercapacitors.
Finally, 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. The project 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) and take place in close cooperation with Dr. George Nounesis (Demokritos), Dr. George Cordoyannis and Dr. Zdravko Kutnjak, (Jožef Stefan Institute, Ljubljana, Slovenia) and Prof. Ioannis Lelidis (University of Athens).