Supply Networks for Healthcare Facilities

Tato bakalářská práce se zabývá porovnáním staré a nové koncepce napájecích sítí pro zdravotnické prostory. Práce ukazuje na příkladech z praxe možnosti monitoringu těchto sítí a zpětnou analýzu nežádoucích událostí.This bachelor thesis deals with comparison of old and new conception of power systems for medical areas. The work shows on the examples from use possibilities of monitoring of these systems and the back analysis of undesirable events.410 - Katedra elektroenergetikyvýborn

Monitoring of Large Power Grids Using Smart Measuring Technology

Tato diplomová práce se zabývá využitím smart měřící techniky pro monitorování rozsáhlých napájecích sítí. Práce ukazuje na příkladech z praxe možnosti propojení této techniky se systémy MaR. Zaměřuje se na monitoring napájecích sítí pro zdravotnické prostory a zpětnou analýzu nežádoucích událostí.This diploma thesis deals with the use of smart measurement technology for monitoring large power networks. The thesis shows the possibilities of interconnection of this technique with MaR systems. It focuses on the monitoring of supply networks for medical areas and the reverse analysis of adverse events.410 - Katedra elektroenergetikyvýborn

Band gap and morphology engineering of hematite nanoflakes from an ex situ Sn doping for enhanced photoelectrochemical water splitting

In this article, we report a simple ex situ Sn-doping method on hematite nanoflakes (coded as MSnO2-H) that can protect the nanoflake (NF) morphology against the 800 degrees C high-temperature annealing process and activate the photoresponse of hematite until 800 nm wavelength excitation. MSnO2-H has been fabricated by dropping SnCl4 ethanol solution on hematite nanoflakes homogeneously grown over the conductive FTO glass substrate and annealed at 500 degrees C to synthesize the SnO2 nanoparticles on hematite NFs. The Sn-treated samples were then placed in a furnace again, and the sintering process was conducted at 800 degrees C for 15 min. During this step, structure deformation of hematite occurs normally due to the grain boundary motion and oriented attachment. However, in the case of MSnO2-H, the outer SnO2 nanoparticles efficiently prevented a shape deformation and maintained the nanoflake shape owing to the encapsulation of hematite NFs. Furthermore, the interface of hematite/SnO2 nanoparticles became the spots for a heavy Sn ion doping. We demonstrated the generation of the newly localized states, resulting in an extension of the photoresponse of hematite until 800 nm wavelength light irradiation. Furthermore, we demonstrated that SnO2 nanoparticles can effectively act as a passivation layer, which can reduce the onset potential of hematite for water splitting redox reactions. The optimized MSnO2-H nanostructures showed a 2.84 times higher photocurrent density and 300 mV reduced onset potential compared with a pristine hematite nanoflake photoanode.Web of Scienc

Magnetite-free Sn-doped hematite nanoflake layers for enhanced photoelectrochemical water splitting

In the present work, we report a preparation strategy for hematite phase-pure photoanodes consisting of Sn-doped hematite nanoflakes/hematite thin film bilayer nanostructure (Sn-HB). This approach is based on a two-step annealing process of pure iron films deposited on fluorine doped tin oxide (FTO) substrates by advanced magnetron sputtering. While the high density hematite ultrathin nanoflakes (HNs) with detrimental iron oxide layers (Fe3O4 and/or FeO) are generated during the first annealing step at 400 degrees C for two hours, the second thermal treatment at 800 degrees C for 15 minutes oxidises all the undesired iron oxide phases to a photoactive hematite layer as well as is providing efficient Sn doping of a drop-casted SnCl4 in order to increase the conductivity. The optimized Sn-HB shows an around 11 times higher photocurrent density (0.71 mA cm(-2) at 1.23 V-RHE) compared with a reference hematite photoanode produced from iron foil under the same conditions.Web of Science911art. no. E20220006

Nanoscale assembly of BiVO4/CdS/CoOx core-shell heterojunction for enhanced photoelectrochemical water splitting

Porous BiVO4 electrodes were conformally decorated with CdS via a chemical bath deposition process. The highest photocurrent at 1.1 V vs. RHE was achieved for a BiVO4/CdS composite (4.54 mA cm(-2)), compared with CdS (1.19 mA cm(-2)) and bare BiVO4 (2.1 mA cm(-2)), under AM 1.5G illumination. This improvement in the photoefficiency can be ascribed to both the enhanced optical absorption properties and the charge separation due to the heterojunction formation between BiVO4 and CdS. Furthermore, the BiVO4/CdS photoanode was protected with a CoOx layer to substantially increase the photostability of the material. The new BiVO4/CdS/CoOx nanostructure exhibited a highly stable photocurrent density of similar to 5 mA cm(-2). The capability to produce O-2 was locally investigated by scanning photoelectrochemical microscope, which showed a good agreement between photocurrent and O-2 reduction current maps. This work develops an efficient route to improve the photo-electrochemical performance of BiVO4 and its long-term stability.Web of Science116art. no. 68

Monitoring of power networks for medical facilities

This bachelor thesis deals with comparison of old and new conception of power systems for medical areas. The work shows on the examples from use possibilities of monitoring of these systems and the back analysis of undesirable events

Elucidating the role of surface states of BiVO4 with Mo doping and a CoOOH co-catalyst for photoelectrochemical water splitting

Bismuth vanadate (BiVO4) is a promising material for photoelectrochemical (PEC) water splitting, however, its PEC performance is limited by the high surface and bulk charge recombination rates. Here we present a comprehensive study to elucidate a recombination phenomenon of BiVO4 that arises with Mo doping. The Mo doping produces multiple effects including the formation of MoOx (reduced form of Mo6+) species and oxygen vacancies (V(O)s) on the surface of the BiVO4 that work in tandem with V4+ species (and MoOx) acting as surfaceactive intermediates (i-SS) providing improved hole transfer to the electrolyte. In contrast, in the absence of V4+ species, the V(O)s can act as recombination centers (r-SS). Further, CoOOH co-catalyst coating is used to minimize such recombination centers. Eventually, a photocurrent enhancement of similar to 37 times (1.1 mA/cm(2) at 1.23 V vs. RHE) and a cathodic shift in onset potential of similar to 500 mV compared to that of pristine BiVO4 (0.03 mA/cm(2) at 1.23 V vs. RHE) is obtained. We carried out in-depth PEC analysis using hole scavenger measurements, PEC impedance spectroscopy, and intensity-modulated photocurrent spectroscopy to elucidate the effect of the surface reduction process upon doping, the impact of Vos, MoOx species and CoOOH layer on the enhanced PEC performance.Web of Science483art. no. 22908

Solar steam generation on scalable ultrathin thermoplasmonic TiN nanocavity arrays

Plasmonic-based solar absorbers exhibit complete light absorption in a sub-?m thickness, representing an alternative to mm-thick carbon-based materials most typically employed for solar-driven steam generation. In this work, we present the scalable fabrication of ultrathin plasmonic titanium nitride (TiN) nanocavity arrays that exhibit 90% broadband solar light absorption within - 250 nm from the illuminated surface and show a fast non-linear increase of performance with light intensity. At 14 Suns TiN nanocavities reach - 15 kg h?1 m?2 evaporation rate and - 76% thermal efficiency, a steep increase from - 0.4 kg h-1 m? 2 and - 20% under 1.4 Suns. Electromagnetic, thermal and diffusion modeling of our system reveals the contribution of each material and reactor component to heat dissipation and shows that a quasi-two-dimensional heat dissipation regime significantly accelerates water evaporation. Our approach to ultrathin plasmonic absorbers can boost the performance of devices for evaporation/desalination and holds promise for a broader range of phase separation processes.Web of Science83art. no. 10582

Robust dual cationic ligand for stable and efficient warm-white light emission in lead-free double perovskite nanocrystals

Bismuth-doped alloyed Cs2Ag1-xNaxInCl6 double perovskite nanocrystals (DP NCs) emerged as a new class of lead-free alternative for single-emitter-based solution-processed white-light-emitting devices (WLEDs). However, their thin-film processing and device fabrication have been limited due to low photoluminescence (PL) quantum yield (QY) and degradation during purification from the as-synthesized crude solution. Moreover, easy reduction of a silver ions by oleylamine also raised concern regarding stability issues of silver based DP NCs. Here, we report a facile synthesis and purification method for shape-pure and monodispersed bismuth-doped alloyed Cs2Ag1-xNaxInCl6 DP NCs with high PL QY and long-term stability. At optimized bismuth-doping, alloyed Cs2Ag1-xNaxInCl6 DP NCs showed warm white-light-emission with a PL QY of 40% due to suppressed non-radiative recombination. The synthesis of highly emissive and stable DP NCs was achieved by utilizing a combination of strongly coordinating silver-trioctylphosphine (Ag-TOP) complex along with additional TOP ligand. The Ag-TOP complex served as a highly reactive silver precursor and prevented the reduction of silver ions into metallic silver. While TOP facilitated the nucleophilic reaction with benzoyl chloride during nucleation and growth stage and forms benzoyl trioctylphosphonium chloride intermediate that served as both halide source and surface capping ligand which enabled the formation of high-quality DP NCs. The high tolerance of DP NCs against common antisolvents such as methyl acetate and isopropanol was attributed to the tight binding of dual cationic ligand benzoyl trioctylphosphonium and oleylammonium cations together with oleate anion to the surface of DP NCs.Web of Science26art. no. 10128