A5059056289- Electrocatalysts for Energy Conversion
- Fuel Cells and Related Materials
- Advanced battery technologies research
- Semiconductor materials and devices
- Luminescence Properties of Advanced Materials
- Electronic and Structural Properties of Oxides
- Near-Field Optical Microscopy
- Inorganic Fluorides and Related Compounds
- Metal-Organic Frameworks: Synthesis and Applications
- Photonic and Optical Devices
- Graphene research and applications
- Plasmonic and Surface Plasmon Research
- Ferroelectric and Negative Capacitance Devices
- Polyoxometalates: Synthesis and Applications
- Electrochemical Analysis and Applications
- Catalytic Processes in Materials Science
- Conducting polymers and applications
- Photoacoustic and Ultrasonic Imaging
- Nanoplatforms for cancer theranostics
- Advanced Memory and Neural Computing
- Optical Coatings and Gratings
- Supercapacitor Materials and Fabrication
- Characterization and Applications of Magnetic Nanoparticles
- ZnO doping and properties
- Carbon Nanotubes in Composites
University of Tartu
2014-2024
Czech Academy of Sciences, Institute of Physics
2016-2022
National Institute of Chemical Physics and Biophysics
2020
University of Helsinki
2020
Non-precious-metal catalysts are promising alternatives for Pt-based cathode materials in low-temperature fuel cells, which is of great environmental importance. Here, we have investigated the bifunctional electrocatalytic activity toward oxygen reduction reaction (ORR) and evolution (OER) mixed metal (FeNi; FeMn; FeCo) phthalocyanine-modified multiwalled carbon nanotubes (MWCNTs) prepared by a simple pyrolysis method. Among bimetallic containing nitrogen derived from corresponding...
Cobalt- and nitrogen-doped carbide-derived carbon/carbon nanotube (CDC/CNT) composites are prepared used as oxygen reduction reaction (ORR) electrocatalysts for an anion exchange membrane fuel cell (AEMFC) cathode. For the doping, high-temperature pyrolysis is applied using a cobalt salt nitrogen precursor (either dicyandiamide, urea, or melamine). During (i) new mesopores formed confirmed by N2 physisorption results, (ii) atomically dispersed present on catalysts detected scanning...
Abstract An efficient method to investigate the microstructure and spatial distribution of nitrogen nitrogen‐vacancy (N‐V) defects in detonation nanodiamond (DND) with primary particle sizes ranging from approximately 3 50 nm is presented. Detailed analysis reveals atomic concentrations as high at% 50% diamond particles smaller than 6 nm. A non‐uniform within larger DND also presented, indicating a preference for location defective central part or at twin boundaries. photoluminescence (PL)...
Abstract Magnetic nanoparticles (M:NPs) are unique agents for in vivo thermal therapies due to their multimodal capacity efficient heat generation under optical and/or magnetic excitation. Nevertheless, transfer from laboratory the clinic is hampered by absence of feedback and influence that external conditions (e.g., agglomeration biological matrix interactions) have on heating efficiency. Overcoming these limitations requires, first, implementation strategies providing sensing M:NPs order...
Iron- and nitrogen-doped carbon-based catalysts are one of the most promising alternatives to platinum-group metal-based ones currently used in fuel cell industry. Here, we study effect ball-milling conditions compositions catalyst precursors comprising a silicon carbide-derived carbon (CDC) on properties final catalysts, importantly their activity toward oxygen reduction reaction (ORR). Ball-milling rates from 100 800 rpm were investigated with 400 proving be optimum value. The...
The use of precious metal electrocatalysts in clean electrochemical energy conversion and storage applications is widespread, but the sustainability these materials, terms their availability cost, constrained. In this research, iron triad-based bimetallic nitrogen-doped carbon (M-N-C) materials were investigated as potential bifunctional for oxygen reduction reaction (ORR) evolution (OER). synthesis FeCo-N-C, CoNi-N-C, FeNi-N-C catalysts involved a precisely optimized carbonization process...
Encapsulation of gold nanorods together with Nd-doped fluorescent nanoparticles in a biocompatible polymer creates multifunctional nanostructures, whose infrared fluorescence allows their subcutaneous localization biological tissues while also adding the ability to measure temperature from emitted light order better monitor light-to-heat conversion during photothermal therapy.
In this study, we present the solvothermal synthesis of LuPO 4 :Pr 3+ (1%) nanocrystals in dimethyl sulfoxide water solvent system. The as-prepared exhibit a relatively high degree crystallinity, along with...
Titanium dioxide coatings of different thicknesses were deposited on the acid-treated multiwall carbon nanotubes (MWCNTs) using controlled atomic layer deposition (ALD). Pt nanoparticles (NP) TiO2/MWCNT supports two methods, viz. sputter-deposition and photo-deposition. Scanning electron microscopy (SEM) scanning transmission (STEM) measurements revealed successful application ALD for TiO2. Both magnetron sputtering photo-deposition found to be efficient well-controlled techniques NPs...
We use two water based synthetic approaches to LaF3:Nd3+ nanoparticles (NPs), hydrothermal microwave treatment (HTMW) and co-precipitation (CO) technique, with different temperature of the reaction mixture study correlation between degree crystallinity NPs their fluorescence properties. showed that spectra quenching kinetics can be a powerful tool reveal crystal lattice defects, namely agglomerations dopant ions (Nd3+) OH− positioned in volume doped NPs. found reduced number such defects as...
Preparation of electrocatalysts often relies on the use multiple starting materials, with examples arising from a single precursor being less common. We have surveyed series heterobivalent scaffolds to identify an iron/benzimidazole-based metal–organic framework as uniform material. By merging catechol and imidazole units together, we get direct entry into highly efficient bifunctional oxygen electrocatalyst, which alleviates need for dopants modifying conditions. demonstrate that by...
High-performance bi- and trimetallic nitrogen-doped nanocarbon catalysts for the electrochemical oxygen reduction reaction (ORR) evolution (OER) were prepared by high-temperature pyrolysis from 5-methylresorcinol, dicyandiamide transition metal (Ni, Fe and/or Co) salts. The electrocatalytic activity of was studied using rotating disc electrode (RDE) method in alkaline solution. NiFeCoNC electrocatalyst showed best bifunctional ORR/OER performance with ΔE value 0.75 V. This is attributed to...
Abstract Atomic layer deposition of HfO2 on unmodified graphene from HfCl4 and H2O was investigated. Surface RMS roughness down to 0.5 nm obtained for amorphous, 30 thick hafnia film grown at 180°C. also deposited in a two-step temperature process where the initial growth about 1 170°C continued up 10–30 300°C. This yielded uniform, monoclinic films with 1.7 10–12 2.5 films. Raman spectroscopy studies revealed that caused compressive biaxial strain graphene, whereas no extra defects were...
Abstract A nanosized island‐like diamond film containing silicon‐vacancy (SiV) centers was grown by microwave plasma CVD on Si substrate. The characterized scanning electron microscope, microRaman, and photoluminescence spectroscopies. Nonuniform spatial localization of the SiV photoluminescent with a density over 1/µm 2 in photoemitting regions is found. Interfering factors hindering registration emission from single center thin nanodiamond films are determined.