A5025927509- High-pressure geophysics and materials
- Diamond and Carbon-based Materials Research
- Crystal Structures and Properties
- Calcium Carbonate Crystallization and Inhibition
- Astro and Planetary Science
- Geology and Paleoclimatology Research
- Geological and Geochemical Analysis
- Paleontology and Stratigraphy of Fossils
- X-ray Diffraction in Crystallography
- Advanced Photocatalysis Techniques
- Catalytic Processes in Materials Science
- Building materials and conservation
- Nuclear Physics and Applications
- Karst Systems and Hydrogeology
- Clay minerals and soil interactions
- Iron oxide chemistry and applications
- Planetary Science and Exploration
- Boron and Carbon Nanomaterials Research
- Mesoporous Materials and Catalysis
- Nuclear reactor physics and engineering
- Magnetic Properties and Synthesis of Ferrites
- Crystallization and Solubility Studies
- Advanced ceramic materials synthesis
- Thermal and Kinetic Analysis
- Carbon Nanotubes in Composites
Research Centre for Astronomy and Earth Sciences
2021-2025
University of Pannonia
2000-2025
Institute for Geological and Geochemical Research
2021-2025
University of Pecs
1998-2024
Konkoly Observatory
2024
University of Illinois Chicago
2022
Institute of Materials and Environmental Chemistry
2012-2021
HUN-REN Research Centre for Natural Sciences
2012-2021
Hungarian Research Network
2021
Research Network (United States)
2021
The search for new nanostructural topologies composed of elemental carbon is driven by technological opportunities as well the need to understand structure and evolution materials formed planetary shock impact events in laboratory syntheses. We describe two families diamond-graphene (diaphite) phases constructed from layered bonded sp3 sp2 units provide a framework classifying members this class materials. nanocomposite structures are identified within both natural diamonds...
Abstract Amorphous calcium carbonate (ACC) is a precursor of crystalline carbonates that plays key role in biomineralization and polymorph evolution. Here, we show several bacterial strains isolated from Hungarian cave produce ACC their extracellular polymeric substance (EPS) shields crystallization. The findings demonstrate bacteria-produced forms water-rich environment at room temperature stable for least half year, which contrast to laboratory-produced needs be stored desiccator kept...
Abstract The unusual physical properties and formation conditions attributed to h-, i-, m- n-nanodiamond polymorphs has resulted in their receiving much attention the materials planetary science literature. Their identification is based on diffraction features that are absent ordinary cubic (c-) diamond (space group: Fd-3m). We show, using ultra-high-resolution transmission electron microscope (HRTEM) images of natural synthetic nanodiamonds, reported consistent with c-diamond containing...
Studies of dense carbon materials formed by bolide impacts or produced laboratory compression provide key information on the high-pressure behavior and for identifying designing unique structures technological applications. However, a major obstacle to studying these is an incomplete understanding their fundamental structures. Here, we report remarkable structural diversity cubic/hexagonally (c/h) stacked diamond association with diamond-graphite nanocomposites containing sp3-/sp2-bonding...
Energy-saving and cost-efficient reaction routes to prepare highly active catalysts for CO2 hydrogenation or solid oxide fuel cells (SOFCs) are enormously important. In this paper, we report a detailed study of dichromate salt [Fe(urea)6]3+, member the [M(urea)6]3+ complex family (M = Fe, Al, Mn, Cr, V, Ti) with oxidizing anions, which is promising precursor Cr-rich mixed chromium iron catalyst prepared at low temperature in phase. The single-crystal X-ray structure, various (infrared,...
Abstract Stromatolites can be traced back to ∼3.5 billion years. They were widespread in the shorelines of ancient oceans and seas. However, they are uncommon nowadays, basic information is lacking about how these unique carbonate structures developed. Here we study unusually thick (3–5 cm) biofilms 79.2 °C outflow from Köröm thermal well (Hungary) demonstrate that its microbial mat – architecture similar fossilized microdigitate stromatolites. Our observations reveal vertically oriented...
Cave carbonates offer insights into past environmental and climate change. A unique type of these deposits, cryogenic cave (CCCs), form by a mechanism known as crystallization. CCCs may through: (1) rapid freezing thin water films on ice surfaces, creating small crystals (typically,
Abstract Speleothem deposits are among the most valuable continental formations in paleoclimate research, as they can be dated using absolute dating methods, and also provide climate proxies. However, alteration processes such post-depositional mineralogical transformations significantly influence paleoclimatic application of their geochemical data. An innovative sampling measurement protocol combined with scanning transmission electron microscopy, X-ray diffraction Fourier transform...
Abstract Diamond is a material of immense technological importance and an ancient signifier for wealth societal status. In geology, diamond forms as part the deep carbon cycle typically displays highly ordered cubic crystal structure. Impact diamonds, however, often exhibit structural disorder in form complex combinations hexagonal stacking motifs. The characterization such diamonds remains challenge. Here, impact from Popigai crater were characterized with range techniques. Using MCDIFFaX...
Copper manganese oxides (CMO) with CuMn2O4 composition are well-known catalysts, which widely used for the oxidative removal of dangerous chemicals, e.g., enhancing CO to CO2 conversion. Their catalytic activity is highest, close those pre-crystalline and amorphous states. Here we show an easy way prepare a stable CMO material at borderline crystalline state (BAC-CMO) low temperatures (<100 °C) followed annealing 300 °C point out its excellent in oxidation reactions. We demonstrate that...
Extensive research has provided a wealth of data on prokaryotes in caves and their role biogeochemical cycles. Ice carbonate rocks, however, remain enigmatic environments with limited knowledge microbial taxonomic composition. In this study, bacterial archaeal communities the Obstans Cave (Carnic Alps, Southern Austria) were analyzed by next-generation amplicon sequencing cultivation strains at 10 °C studying metabolism. The most abundant taxa uncultured Burkholderiaceae Brevundimonas spp....
Several mechanisms and intermediate steps have been proposed to explain the transformation of graphite diamond. However, mechanism continues be debated, in part because that is incompletely transformed diamond has not reported; although such material could used better understand diamond-forming process. Here we report discovery nano-sized grains interstratified from Gujba, an extraterrestrially shocked meteorite. We use high-resolution transmission electron microscopy (HRTEM) data these show...
We reported on the synthesis of nanosized hydroxyapatite particles by wet chemical precipitation method and consolidation nanoparticles spark plasma sintering. studied effect temperature particle size phase composition obtained HAp. During beyond HAp, another supposedly nonstoichiometric HAp was also formed as a by-product that can be detected thermal analysis combined with XRD. Its amount gradually decreased increase in practically disappeared at 80 °C. Using this nanopowder for sintering,...
Nanodiamonds (ND) with 1-5 nm dimensions found in meteorites or produced by chemical vapour deposition (CVD) and detonation synthesis are typically described terms of an sp3-bonded carbon network. However, ultra-high-resolution transmission electron microscopy (uHRTEM) combined density functional theory (DFT) modelling leads to a different structural interpretation. uHRTEM imaging nanodiffraction studies many NDs show six-fold symmetry features whose identity has long been controversial. We...