Tomasz M Stawski

Tomasz M Stawski
Bundesanstalt für Materialforschung und -prüfung | BAM · Division 6.3 Structural Analysis

Dr

About

91
Publications
15,481
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967
Citations
Citations since 2016
61 Research Items
869 Citations
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
Additional affiliations
February 2013 - December 2015
University of Leeds
Position
  • PostDoc Position
September 2007 - December 2011
University of Twente
Position
  • PhD Student

Publications

Publications (91)
Preprint
Full-text available
We present how mesoporosity can be engineered in transition metal phosphate (TMPs) materials in a template-free manner. The method involves a transformation of a precursor metal phosphate phase, M-struvite (NH4MPO4·6H2O, M = Mg2+, Ni2+, Co2+, Nix2+Co1-x2+), and it relies on the thermal decomposition of crystalline M-struvite precursors to an amorph...
Preprint
Full-text available
We present how mesoporosity can be engineered in transition metal phosphate (TMPs) materials in a template-free manner. The method involves a transformation of a precursor metal phosphate phase, M-struvite (NH4MPO4·6H2O, M = Mg2+, Ni2+, Co2+, Nix2+Co1-x2+), and it relies on the thermal decomposition of crystalline M-struvite precursors to an amorph...
Preprint
Full-text available
We present how mesoporosity can be engineered in transition metal phosphate (TMPs) materials in a template-free manner. The method involves a transformation of a precursor metal phosphate phase, M-struvite (NH4MPO4·6H2O, M = Mg2+, Ni2+, Co2+, Nix2+Co1-x2+), and it relies on the thermal decomposition of crystalline M-struvite precursors to an amorph...
Article
Full-text available
Industrial and agricultural waste streams (waste water, sludges, tailings, etc.) which contain high concentrations of NH4+, PO43–, and transition metals are environmentally harmful and toxic pollutants. At the same time, phosphorous and transition metals constitute highly valuable resources. Typically, separate pathways have been considered to extr...
Preprint
Full-text available
We show how historical gypsum plaster preparation methods affect the microstructure and the nanoscale hydrophilic properties of the final stucco materials. We reproduced a traditional Persian recipe (Gach-e Koshteh, ~14th c. AD), which involves a continuous mechanical treatment during plaster hydration. The Koshteh samples were compared with a lab-...
Preprint
Full-text available
An anion doped aluminium chlorofluoride AlCl0.1F2.8(OTeF5)0.1 (ACF-teflate) was synthesized. The material contains pentafluoroorthotellurate (teflate) groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spe...
Article
Full-text available
Metal nanoparticles have a substantial impact across different fields of science, such as photochemistry, energy conversion, and medicine. Among the commonly used nanoparticles, silver nanoparticles are of special interest due to their antibacterial properties and applications in sensing and catalysis. However, many of the methods used to synthesiz...
Article
Full-text available
A new hetero‐bimetallic polyoxometalate (POM) nano ring was synthesized in a one‐pot procedure. The structure consists of tetrameric units containing four bismuth‐substituted monolacunary Keggin anions including distorted [BiO8] cubes. The nano ring is formed via self ‐assembly from metal precursors in aqueous acidic medium. The compound (NH 4 ) 16...
Article
Full-text available
Sulfate is abundant in the environment and, as a result, sulfate-containing minerals constitute a large and important focus of research [...]
Preprint
Metal nanoparticles have a substantial impact across different fields of science, such as photochemistry, energy conversion, and medicine. Among the commonly used nanoparticles, silver nanoparticles are of special interest due to their antibacterial properties and applications in sensing and catalysis. However, many of the methods used to synthesiz...
Article
Full-text available
Significance Many people perceive crystals as the embodiment of perfect order, although in reality, it is well understood that monocrystals possess imperfections. By considering large anhydrite crystals from the famous Naica Mine (“Cueva de los cristales”), an extended picture begins to emerge, revealing a suite of correlated self-similar void defe...
Preprint
Waste water containing high concentrations of NH4+, PO43- and transition metals M2+ are environmentally harmful due to environmental pollution and toxicity. Different pathways were perused to extract hazardous transition metals or phosphate separately. Investigations on the simultaneous remove of multiple components have barely reported. We report...
Preprint
Full-text available
In recent years, we have come to appreciate the astounding intricacy of the formation process of minerals from ions in aqueous solutions. In this context, a number of studies have revealed that nucleation in the calcium sulfate system is non-classical, involving the aggregation and reorganization of nanosized prenucleation particles. In a recent wo...
Article
Full-text available
Clays are crucial mineral phases in Earth’s weathering engine, but we do not know how they form in surface environments under (near-)ambient pressures and temperatures. Most synthesis routes, attempting to give insights into the plausible mechanisms, rely on hydrothermal conditions, yet many geological studies showed that clays may actually form at...
Article
Full-text available
CaSO4 minerals (i.e. gypsum, anhydrite and bassanite) are widespread in natural and industrial environments. During the last several years, a number of studies have revealed that nucleation in the CaSO4-H2O system is non-classical, where the formation of crystalline phases involves several steps. Based on these recent insights we have formulated a...
Preprint
CaSO4 minerals (i.e. gypsum, anhydrite and bassanite) are widespread in natural and industrial environments. During the last several years, a number of studies have revealed that nucleation in the CaSO4-H2O system is non-classical, where the formation of crystalline phases involves several steps. Based on these recent insights we have formulated a...
Article
Full-text available
The controlled crystallisation of struvite (MgNH 4 PO 4 ·6H 2 O) is a viable means for the recovery and recycling of phosphorus (P) from municipal and industrial wastewaters. However, an efficient implementation of this recovery method in water treatment systems requires a fundamental understanding of struvite crystallisation mechanisms, including...
Article
The solution-mediated formation of calcium sulfate minerals, i.e. gypsum, anhydrite and bassanite, is a common process in both natural and engineered settings. It plays a key role in the global sulfur cycle and serves as an indicator of past environmental conditions on Earth and Mars. Products relying on the crystallization of these minerals have b...
Article
Full-text available
Understanding the gypsum (CaSO4·2H2O) formation pathway from aqueous solution has been the subject of intensive research in the past years. This interest stems from the fact that gypsum appears to fall into a broader category of crystalline materials whose formation does not follow classical nucleation and growth theories. The pathways involve tran...
Preprint
Full-text available
Although clays are crucial mineral phases in Earth's weathering engine, it is unclear how they form in surface environments under (near-)ambient pressures and temperature. Most synthesis routes, attempting to give insights into the plausible mechanisms, rely on hydrothermal conditions, yet many geological studies showed that clays may actually form...
Article
Full-text available
Calcium sulfate minerals are found in nature as three hydrates: gypsum (CaSO4·2H2O), bassanite (CaSO4·0.5H2O), and anhydrite (CaSO4). Due to their relevance in natural and industrial processes, the formation pathways of calcium sulfates from aqueous solution have been the subject of intensive research and there is a growing body of literature, sugg...
Preprint
Full-text available
The understanding of the gypsum (CaSO4.2H2O) formation pathway from aqueous solutions has been the subject of intensive research in the last couple of years. This interest stems from the fact that gypsum appears to fall into a broader category of crystalline materials whose formation does not follow classical nucleation and growth theories. The pat...
Article
Full-text available
Mesoporous phosphates are a group of nanostructured materials with promising applications, particularly in biomedicine and catalysis. However, their controlled synthesis via conventional template-based routes presents a number of challenges and limitations. Here, we show how to synthesize a mesoporous magnesium phosphate with a high surface area an...
Article
Full-text available
A quantitative understanding of aggregation mechanisms leading to the formation of composites of inorganic nanoparticles (NPs) and proteins in aqueous media is of paramount interest for colloid chemistry. In particular, the interactions between silica (SiO2) NPs and lysozyme (LZM) have attracted attention, because LZM is well-known to adsorb strong...
Preprint
Full-text available
Calcium sulfate minerals are found under the form of three crystalline phases: gypsum (CaSO4.2H2O), bassanite (CaSO4.0.5H2O), and anhydrite (CaSO4). Due to its relevance in natural and industrial processes, the formation pathways of these calcium sulphate phases from aqueous solution have been the subject of intensive research. There is a growing b...
Article
Full-text available
Amorphous silica is a common precipitate in modern and ancient hot springs and in geothermal power plants, yet the corresponding precipitation rates and mechanisms are still highly debated, primarily due to the plethora of parameters that can affect the reactions in natural waters. Here, we report the results from a first ever industrial-scale time...
Article
Iron sufides are important mineral phases in natural environments where they control global elemental cycles. Fe-S phases have been suggested to form through transformation of several possible precursors to finally reach stable crystalline structures. Mackinawite is a metastable intermediate, of which a full chemical and structural characteristisat...
Article
In complex chemical syntheses (e.g., coprecipitation reactions), nucleation, growth, and coarsening often occur concurrently, obscuring the individual processes. Improved knowledge of these processes will help to better understand and optimize the reaction protocol. Here, a form‐free and model independent approach, based on a combination of time‐re...
Article
Full-text available
Iron sulfur (Fe-S) phases have been implicated in the emergence of life on early Earth due to their catalytic role in the synthesis of prebiotic molecules. Similarly, Fe-S phases are currently of high interest in the development of green catalysts and energy storage. Here we report the synthesis and structure of a nanoparticulate phase (FeSnano) th...
Preprint
A quantitative understanding of aggregation mechanisms leading to the formation of inorganic nanoparticles (NPs) and protein composites in aqueous media is of paramount interest for colloid chemistry. In particular, the interactions between silica (SiO2) NPs and lysozyme (LZM) have attracted attention, because LZM is well-known to adsorb strongly t...
Article
Full-text available
Can we control the crystallization of solid CaCO3 from supersaturated aqueous solutions and thus mimic a natural process predicted to occur in living organisms that produce biominerals? Here we show how we achieved this by confining the reaction between Ca²⁺ and CO3²⁻ ions to the environment of nanosized water cores of water-in-oil microemulsions,...
Article
Full-text available
Interactions between silica and proteins are crucial for the formation of biosilica and the production of novel functional hybrid materials for a range of industrial applications. The proteins control both precipitation pathway and the properties of the resulting silica-organic composites. Here we present data on the formation of silica-lysozyme co...
Article
Full-text available
Can we control the crystallization of solid CaCO3 from supersaturated aqueous solutions and thus mimic a natural process predicted to occur in living organisms that produce biominerals? Here we show how we achieved this by confining the reaction between Ca2+ and CO32- ions to the environment of nanosized water cores of water-in-oil microemulsions....
Chapter
Calcium sulfate phases are among the most dominant evaporitic minerals and occur in large amounts both on Earth and Mars. In addition, they find broad application across various fields of industrial relevance. Despite its obvious significance, the CaSO4–H2O system has received surprisingly little attention in the recent flurry of studies addressing...
Chapter
Silica (SiO2) and alumina (Al2O3) nanophases control several important global element cycles. They play a crucial role in rock weathering and thus affect and are affected by Earth’s response to global climate change. The phases that form through various precipitation and crystallisation reactions, often adjacent to each other, are also important in...
Article
The pathways of CaCO3 crystallisation are manifold, often involving one or several metastable amorphous or nanocrystalline intermediate phases. The presence of such intermediates is often overlooked or not observed, because they are short-lived and/or occur at small molar fractions. However, their occurrence does not just impact the mechanisms and...
Article
Full-text available
Synchrotron-based small-and wide-angle X-ray scattering (SAXS/WAXS) was used to examine in situ the precipitation of gypsum (CaSO 4 ·2H 2 O) from solution. We determined the role of (I) supersaturation, (II) temperature and (III) additives (Mg 2+ and citric acid) on the precipitation mechanism and rate of gypsum. Detailed analysis of the SAXS data...
Poster
Full-text available
We performed liquid cell scanning transmission electron microscopy (LCSTEM) on reverse micelles containing supersaturated solutions of calcium and carbonate. No precipitation was observed as long as the micelles remained intact. However, a rapid formation of vaterite occurred upon the addition of ethanol leading to the removal of the surfactant sta...
Article
Full-text available
Densely packed surface fractal aggregates form in systems with high local volume fractions of particles with very short diffusion lengths, which effectively means that particles have little space to move. However, there are no prior mathematical models, which would describe scattering from such surface fractal aggregates and which would allow the s...
Article
Full-text available
Ferrihydrite is the most common iron oxyhydroxide found in soil and is a key sequester of contaminants in the environment. Ferrihydrite formation is also a common component of many treatment processes for clean-up of industrial effluents. Here we characterize ferrihydrite formation during the titration of an acidic ferric nitrate solution with NaOH...
Article
A molecular understanding of the formation of solid phases from solution would be beneficial for various scientific fields. However, nucleation pathways are still not fully understood, whereby the case of iron(oxy)(hydr)oxides poses a prime example. We show that in the pre-nucleation regime, thermodynamically stable solute species up to a few nanom...
Article
Full-text available
The formation pathways of gypsum remain uncertain. Here, using truly in situ and fast timeresolved small-angle X-ray scattering, we quantify the four-stage solution-based nucleation and growth of gypsum (CaSO4 2H2O), an important mineral phase on Earth and Mars. The reaction starts through the fast formation of well-defined, primary species of o3 n...
Data
Supplementary Figures 1-7, Supplementary Tables 1-2, Supplementary Equations 1-9, Supplementary Notes 1-9 and Supplementary References.
Chapter
This chapter focuses on time-resolved studies of nanostructure development in sol-gel liquids, that is, diluted sols, wet gels, and drying thin films. The most commonly investigated classes of sol-gel materials are silica, organically modified silica, template-directed mesostructured silica, titania and titania-based materials, zirconia and zirconi...
Conference Paper
Full-text available
Quantifying the initial stages of solution-based nucleation and the mechanisms leading to iron sulphide phase formation are both critical to understanding the role of iron sulphides in the global S and Fe biochemical cycles. Furthermore, nanoparticulate iron sulphides, due to their high surface reactivity and affinity for heavy metals are crucial p...
Conference Paper
Calcium carbonates are the most ubiquitous functional biomineral in nature. Microscopic living organisms direct CaCO3 precipitation from aqueous ions with an unprecedented level of control and this underpins a vast array of Earth system processes, including the global carbon cycle. For example, cocolithophores internally mineralize structurally hig...
Article
Nanocrystalline barium titanate (8–10 nm crystallite size) was prepared at temperatures of 23–78 °C through reaction of a modified titanium alkoxide precursor in benzyl alcohol with barium hydroxide octahydrate. The room temperature formation of a perovskite phase from solution is associated with the use of benzyl alcohol as solvent medium. The for...
Article
Full-text available
A fast and non-destructive method based on X-ray reflectivity was developed to determine the density of sol–gel derived ceramic thin films, without prior assumptions on the microstructure of the system. The thin film density is calculated from the critical angle θc, i.e. the maximum angle at which total external reflection is still observed, which...
Conference Paper
Full-text available
Reverse microemulsions are thermodynamically stable water-in-oil suspensions (i.e., micelles stabilised by an interface surfactant). Such water-in-oil droplets are typically 1-10 nm in diameters and each can carry dissolved salt ions and exchange their contents upon collisions. Thus, they are ideal for mimicking mineral precipitation in highly conf...
Conference Paper
Full-text available
Nanocrystalline iron sulphide phases (nominally FeS) are crucial for controlling the global S and Fe cycles through their dominant role in modern and ancient euxinic water columns and sediments. Furthermore, nanoparticulate FeS phases are believed to be the prime catalyst for prebiotic organic synthesis reactions. However, the early stages of FeS n...
Article
In situ and time-resolved structural information about emergent microstructures that progressively develop during the formation of inorganic or biologically mediated solid phases from solution is fundamental for understanding of the mechanisms driving complex precipitation reactions, for example, during biomineralization. In this brief chapter, we...
Conference Paper
Full-text available
Barium titanate (BTO) is used as a high-k dielectric material in multi-layer ceramic capacitors. The minimum BTO film thickness that can be achieved commercially with tape-casting methods is about 0.5 µm. Further downscaling requires finer powders and new deposition techniques, such as sol-gel processing. We recently developed a novel low-temperatu...
Article
The evolution of structure in sol-gel derived mixed bridged silsesquioxane-niobium alkoxide sols and drying thin films was monitored in situ by small-angle X-ray scattering. Since sol-gel condensation of metal alkoxides proceeds much faster than that of silicon alkoxides, the incorporation of d-block metal dopants into silica typically leads to for...
Article
The evolution of phase and defect structure in BaTiO3 nanopowders synthesized by an alkoxide–hydroxide process in benzyl alcohol under reflux conditions were investigated. As-prepared powders were heat-processed at temperatures ranging from 250 to 850 °C. X-ray powder diffraction (XRD) showed that BaTiO3 remained cubic with crystallite size below 3...