Ce ion surface-modified TiO2 aerogel powders: a comprehensive study of their excellent photocatalytic efficiency in organic pollutant removal
New Journal of Chemistry, 2021
The surface modification of TiO2 aerogel powders by cerium ions has led to enhanced photoinduced ... more The surface modification of TiO2 aerogel powders by cerium ions has led to enhanced photoinduced properties.
Supporting role of silica nanospheres with surface modified by silver nanoparticles in antibacter... more Supporting role of silica nanospheres with surface modified by silver nanoparticles in antibacterial photodynamic therapy (APDT), was studied. Optical and antibacterial properties of a photosensitizer-Photolon ® in the presence of silica based nanopowders doped with silver nanoparticles, were determined. Various concentrations of Photolon ® solution and nanomaterials have been prepared in order to examine the optical absorption and the effectivity of antibacterial activity. It was found that the maximum optical absorption of Photolon ® depends on its concentration and can be enhanced by the presence of silver nanoparticles. The presence of silver nanoparticles can thus lead to a reduction of the concentration of the photosensitizer while achieving the same level of antibacterial efficacy as in case of higher photosensitizer concentration without the presence of silver nanoparticles. Efficiency of APDT was enhanced by combination of nanosilver doped silica nanospheres, which have powerful antimicrobial and bactericidal activity and photoactive photosensitizer-Photolon ® .
Acta Crystallographica Section C Crystal Structure Communications, 1997
In both {N-[(2-hydroxyphenyl)methylene]-(S)-alaninato-O, N, O' } (pyrazole-N 2)copper(If) dihydra... more In both {N-[(2-hydroxyphenyl)methylene]-(S)-alaninato-O, N, O' } (pyrazole-N 2)copper(If) dihydrate, [Cu(C 10H9-NO3)(C3H4N2)].2H20, (I), and {N-[(2-hydroxyphenyl)methylene]-(R, S)-alaninato-O, N, O' } (pyrazole-N 2)copper(U) pyrazole solvate, [Cu(C10H9NO3)(C3H4N2)].-C3H4N2, (II), the Cu H ion adopts a similar axially distorted square-pyramidal coordination. The basal plane is formed by the tridentate Schiff base N-salicylidenealaninato dianion (TSB 2-) and the pyrazole ligand. The apex of the pyramid is occupied by a carboxylic O atom from the neighbouring chelate. The cooperative ordering and the apic~ distance [2.978 (3) A in (I) compared with 2.366 (3)A in (II)] are the two main differences between the two complexes. The stacked Cu(TSB) complexes within (I) form polymeric chains by translation parallel to [100]. The apically bridged Cu(TSB) complexes of (II) form zigzag chains parallel to [010] via the 21 operator. The influence of the configuration
Chapter 2. Photocatalytic Effects in Doped and Undoped Titania
Nanoscience & Nanotechnology Series, 2011
Improving the spectral sensitivity of photocatalysts may significantly enhance photoprocesses by ... more Improving the spectral sensitivity of photocatalysts may significantly enhance photoprocesses by distinctly absorbing more light. The design of more selective photocatalysts that can be activated by visible light and can be applied in medical diagnosis or therapy (in cancer treatment, implantology or as an antibacterial material) or novel photocatalysts for the production of energy resources (from biomass or from water splitting) are among the major goals of application for doped and undoped titania photocatalysts in biological and chemical applications. Here, we discuss surface charge generation and photocatalysis in nano-titania and methods of obtaining a shift to a higher wavelength for this photocatalytic transition. With some examples, we also show how photocatalysis can be probed.
Preliminary studies of thin metal oxide films prepared by deposition of an aerosol generated ultrasonically from aqueous nitrate solutions
Thin Solid Films, 1997
Thin Co, Co-Fe and Co-Fe-Cr metal oxide films were prepared by deposition of an aerosol generated... more Thin Co, Co-Fe and Co-Fe-Cr metal oxide films were prepared by deposition of an aerosol generated by ultrasonic excitations from aqueous nitrate solutions. Commercial gray glass has been used as substrates. Thermogravimetric (TG and DTG) measurements of initial nitrate components as well as their homogenized mixtures were performed and optical properties, i.e. reflectance and transmittance of the deposited films in
International Journal of Inorganic Materials, 2001
The role of Ag-additions in the synthesis of bulk YBa Cu O is extremely varied. In order to separ... more The role of Ag-additions in the synthesis of bulk YBa Cu O is extremely varied. In order to separate and understand some aspects of 2 3 7 these introductions, this paper describes the synthesis of two series of bulk samples with different thermal histories as a function of their silver content up to very high loadings (0-80 wt.%), which may have industrial significance. Their morphological and thermal characteristics are discussed and their superconducting properties are studied in detail using AC and DC susceptometry at high and low field. They exemplify the role of silver as flux at high temperatures and as mediator of oxygen transport at lower temperatures.
The use of thick films becomes more and more important in particular for electronic and microelec... more The use of thick films becomes more and more important in particular for electronic and microelectronic applications. The term “thick film ” does not relate so much to the thickness of the film but more to the kind of deposition. Thick films are made by low-priced processes such as doctor (dr) blading, screen-printing, or spraying methods, etc. The preparation of thick films of ceramic material by these methods generally implies a processing sequence of the following steps: preparation of the oxide powders; preparation of pastes and slurries; painting/printing, etc.of the pastes onto a suitable substrate; drying at low temperature; and sintering at high temperature to get a consolidated layer. These technologies and the fabricated thick films of thermoresistive and superconducting materials will be discussed.
Superconducting Hg,Pb Ba CaCu O thin films have been prepared in a two step process. Approximativ... more Superconducting Hg,Pb Ba CaCu O thin films have been prepared in a two step process. Approximatively 0.2-mm-thick 2 2 y Ž. Ba-Ca-Cu-O or Pb-Ba-Ca-Cu-O precursor films have been deposited on MgO 100 monocrystalline substrates by a sequential evaporation method. Hg was then introduced into the precursor in a closed silica tube. The surface morphology was characterized by SEM, the composition of the superconducting phase was determined by wave dispersive X-ray electron microanalysis. Phase identification was carried out by X-ray diffraction. The c-axis-oriented plate-like crystals of the Ž. Hg-1212 and Hg,Pb-1212 phase were weakly connected. Although coverage of the substrate was uneven, we were able to measure transport superconductivity. The partial substitution of Hg by Pb did not significantly influence the T values. For c both the Pb-free and Pb-doped Hg-1212 samples T-values of about 132 K and the zero resistance temperatures T from cŽon. cŽ0.
Basic and substituted superconductors in the homologous series BizSr2Ca ._ ~Cu. 02,+4+ r, Bi 2 _x... more Basic and substituted superconductors in the homologous series BizSr2Ca ._ ~Cu. 02,+4+ r, Bi 2 _x/zSr2 xi2LxCa. _ iCunO2n+4+,,and Bi:Sr 2 xL~Ca. _ iCu,,Oz.+a+~.(L = Sn, Pb or Ag, x = 0-0.4, n = 2, 3 or 4) have been synthesized. All the prepared ceramic samples show superconducting behaviour with zero resistance at T~ = 70 to 85 K. The compounds with n=3 or 4 showed onset temperature around I I5K indicating involvement of a disproportionate solid-state reaction and formation of a two-phase system. The phase involving tin or lead oxides showed similar superconducting properties. Final rapid quenching of samples contributed to preservation of the high temperature equilibria with higher solubility of tin oxide in the quaternary system Bi-Sr Ca-Cu O. Silver was not soluble but precipitated in a colloidal form at interfaces between the crystalline grains.
Thin-textured YBazCu3Oy(Ag) films were prepared by a new CVD process consisting of aerosol deposi... more Thin-textured YBazCu3Oy(Ag) films were prepared by a new CVD process consisting of aerosol deposition and low temperature annealing, both operations not exceeding 600°C. MgO and SrTiO 3 single crystals were used as substrates. The stoiehiometry of the prepared films was not ideal 1-2-3, having the atomic quotient of copper always lower than 3. For an unoptimized preparation process, the onset temperatures were around 80 K and the zero resistance T,, values around 70 K. Properties of samples obtained by low-temperature annealing are compared with those obtained by high temperature annealing. "Cleaning" effect of vacuum-annealing upon removing the nitrate and hydroxide groups from the prepared films is supposed.
The 1st International Electronic Conference on Processes: Processes System Innovation
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Contribution of photocatalytic and Fenton-based processes in nanotwin structured anodic TiO2 nanotube layers modified by Ce and V
Dalton Transactions
Contribution of photocatalysis and Fenton-based processes for the degradation of aqueous organic ... more Contribution of photocatalysis and Fenton-based processes for the degradation of aqueous organic pollutants.
We present results which describe procedures of the preparation and patterning of Hg,Re-Ba-Ca-Cu-... more We present results which describe procedures of the preparation and patterning of Hg,Re-Ba-Ca-Cu-O superconducting films suitable for coplanar structures usable as possible photodetectors and for microbridges. We compare structural and electrical properties of the final films from the point of their applicability for photodetectors. Our prepared Re-doped Hg-based films on LaAlO 3 substrate are continuous with a sufficient adhesion to the substrate and with a maximum zero resistance critical temperature T C0 $ 122 K. The X-ray diffraction of all the films confirmed the Hg-1212 phase beside the minor Hg-1223 phase and intergrowth phases in some cases. In spite of epitaxial character of the final Hg-based films, the microwave and magnetic measurements suggest a possible existence of nonstoichiometric material between the grains which we register as a presence of weak links near the transition into the superconducting state. We show some electrical properties of the prepared superconducting structures, too. The prepared coplanar structures show ultrafast photoresponse signal to incident laser pulse.
Piezoelectricity in Sr doped thick films of hydroxyapatite
The current study reports the synthesis, characterization and tape casting of strontium substitut... more The current study reports the synthesis, characterization and tape casting of strontium substituted into the calcium sublattice of hydroxyapatite in range of (0–100 mol%). The XRD powder data reveals that a primary HAp phase as well as secondary Ca3(PO4)2 (β-TCP) phase coexist. Our analysis shows that Sr+2 preferentially occupies the HAp lattice sites rather than β-TCP. Developed free-standing tapes of HAp offer unique possibility of custom designed solutions for biomedical applications by controlling shape size and tuned electrical properties. We report piezoelectricity in Sr doped hydroxyapatites thick films, the piezoelectric coefficient is an order of magnitude higher than what has been previously obtained in PLD deposited hydroxyapatite films [15]. The piezoelectricity shows slight improvement with the Sr doping. Despite low piezoelectric coefficient, the generated voltage is of the order of mV which is high enough to have physiological relevance since the resting potential of ...
International Journal of Inorganic Materials, 1999
The deposition of aqueous aerosols of nitrates led to precursor films with a thickness of 3-5 mm.... more The deposition of aqueous aerosols of nitrates led to precursor films with a thickness of 3-5 mm. The Ba-Ca-Cu-O and Pb-Sr-Ba-Ca-Cu-O as-deposited layers were calcined at 850-8708C. Thallination of Ba-Ca-Cu-O precursors at relatively high Tl O 2 partial pressure resulted in Tl-2212 films with preferred c-axis orientation. Partial substitution of Pb for Tl and of Sr for Ba yielded randomly oriented Tl-1212 films. Deposition of Ba(II)-, Ca(II)-and Cu(II)-bis(2,4-pentanedionates) on polycrystalline silver tapes produced-after subsequent thallination-textured Tl-2223 films with a thickness of about 1 mm. Some aspects of the chemical reactions proceeding during the aerosol deposition and in the thallination step are discussed on the basis of thermogravimetric measurements.
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Papers by Gustav Plesch