Pokročilé nízkodimenzionální nanomateriály


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Now showing 1 - 5 of 48
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    Bio-AFM exploits enhanced response of human gingival fibroblasts on TiO2 nanotubular substrates with thin TiO2 coatings
    (ELSEVIER, 2023-12-01) Baishya, Kaushik; Vrchovecká, Katarina; Alijani, Mahnaz; Rodriguez Pereira, Jhonatan; Thalluri, Sitaramanjaneya Mouli; Pávková Goldbergová, Monika; Přibyl, Jan; Macák, Jan
    The present work studies anodic TiO2 nanotube (TNT) layers and their surface modifications for enhancing the cell behavior of human gingival fibroblast cells (hGFs) with the contribution of bio-AFM (Atomic Force Micro-scopy) method. TNT layers, prepared via electrochemical anodization of Ti, with an average tube diameter of 15, 30, and 100 nm, were used as primary substrates for the study. Flat Ti foils were used as reference substrates. Part of the substrates was coated by ultrathin TiO2 coatings (approximate to 0.3 nm thin) using Atomic Layer Deposition (ALD). The cell growth and adhesion of hGFs on the TNT layers and Ti foils were compared between ALD coated and uncoated ones. The supplemental coatings altered the surface chemistry of the TNT layers, particularly shading the fluorine and carbon impurities within anodic TiO2, while preserving the original structure and morphology. The presented approach of very mild surface modification remarkably effects the material's biocompatibility and possess great prospect as implant materials. For the first time, the TNT/cell interface was investigated using bio-AFM in terms of Young's modulus, stiffness, cell adhesive force and roughness. Improved biocompatibility was studied in terms of increased cell viability, density, cell cytoskeleton orientation and overall stiffness of the hGFs.
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    Gas Phase Photocatalysis on Large-Scale TiO2 Nanotube Layers for Pollutant Degradation: Influence of the Nanotube Crystallinity
    (American Chemical Society, 2023-09-12) Sopha, Hanna Ingrid; Baudys, Michal; Sepúlveda Sepúlveda, Lina Marcela; Rusek, Jakub; Hromádko, Luděk; Rodriguez Pereira, Jhonatan; Krýsa, Josef; Macák, Jan
    In this work, for the first time, the influence of the crystallinity of TiO2 nanotube (TNT) layers on their gas phase photocatalytic performance was investigated under ISO standards using two distinct model pollutants, namely, hexane and acetaldehyde. TNT layers (1 mu m thick) on 5 x 10 cm(2) large Ti substrates were employed in this work due to their excellent adhesion to Ti upon annealing at high temperatures. Annealing of the TNT layers was carried out in a temperature range between 300 and 700 degrees C, resulting in TNT layers with different crystallinities, i.e., from the pure anatase phase to an 85% rutile phase. The superior performance of the TNT layers annealed at 600 degrees C with mixed anatase and rutile phase compared to other specimens was observed for both model pollutants, stemming from the band alignment between the two crystalline phases. For higher annealing temperatures, however, the photocatalytic performance of the TNT layers was reduced due to a partial disintegration of the TNTs. No surface contamination of the TNT layers with residues of pollutant degradation products was observed after experiments.
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    Flow-through Gas Phase Photocatalysis Using TiO2 Nanotubes on Wirelessly Anodized 3D-Printed TiNb Meshes
    (American Chemical Society, 2023-07-12) Sopha, Hanna Ingrid; Kashimbetova, Adelia; Baudys, Michal; Chennam, Pavan Kumar; Sepúlveda Sepúlveda, Lina Marcela; Rusek, Jakub; Kolíbalová, Eva; Čelko, Ladislav; Montufar Jimenez, Edgar Benjamin; Krýsa, Josef; Macák, Jan
    In this work, for the first time 3D Ti-Nb meshes of differentcomposition,i.e., Ti, Ti-1Nb, Ti-5Nb, and Ti-10 Nb, were produced by direct inkwriting. This additive manufacturing method allows tuning of the meshcomposition by simple blending of pure Ti and Nb powders. The 3D meshesare extremely robust with a high compressive strength, giving potentialuse in photocatalytic flow-through systems. After successful wirelessanodization of the 3D meshes toward Nb-doped TiO2 nanotube(TNT) layers using bipolar electrochemistry, they were employed forthe first time for photocatalytic degradation of acetaldehyde in aflow-through reactor built based on ISO standards. Nb-doped TNT layerswith low concentrations of Nb show superior photocatalytic performancecompared with nondoped TNT layers due to the lower amount of recombinationsurface centers. High concentrations of Nb lead to an increased numberof recombination centers within the TNT layers and reduce the photocatalyticdegradation rates.
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    Polymeric ionic liquid-based formulations for the fabrication of highly stable perovskite nanocrystal composites for photocatalytic applications
    (Royal Society of Chemistry, 2023-03-09) Miralles-Comins, Sara; Zanatta, Marcileia; Gualdron-Reyes, Andres F.; Rodriguez Pereira, Jhonatan; Mora-Sero, Ivan; Sans, Víctor
    Halide perovskite nanocrystals (PNCs) have emerged as potential visible-light photocatalysts because of their outstanding intrinsic properties, including high absorption coefficient and tolerance to defects, which reduces non-radiative recombination, and high oxidizing/reducing power coming from their tuneable band structure. Nevertheless, their sensitivity to humidity, light, heat and water represents a great challenge that limits their applications in solar driven photocatalytic applications. Herein, we demonstrate the synergistic potential of embedding PNCs into polymeric ionic liquids (PILs@PS) to fabricate suitable composites for photodegradation of organic dyes. In this context, the stability of the PNCs after polymeric encapsulation was enhanced, showing better light, moisture, water and thermal stability compared to pristine PNCs for around 200 days.
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    Enhanced C-O Functionality on Carbon Papers Ensures Lowering Nucleation Delay of ALD for Ru towards Unprecedented Alkaline HER Activity
    (Wiley VCH, 2023-04-17) Thalluri, Sitaramanjaneya Mouli; Rodriguez Pereira, Jhonatan; Zazpe Mendioroz, Raúl; Bawab, Bilal; Kolíbalová, Eva; Jelínek, Luděk; Macák, Jan
    The success in lowering the nucleation delay for Atomic Layer Deposition (ALD) of Ru on carbon surfaces is mitigated by constructive pretreatments resulting enhancement of C-O functionality. Treatment of the carbon papers (CP) allowed Ru species deposition for minimum number of ALD cycles (25 cycles) with good conformality. The development of electrocatalysts from single atoms to nanoparticles (NPs) on conductive supports with low metal loadings, thus improving performance, is essential in electrocatalysis. For alkaline hydrogen evolution reaction, ALD decorated CPs with Ru exhibit low onset potentials of approximate to 4.7 mV versus reversable hydrogen electrode (RHE) (at 10 mA cm(-2)) and a high turnover frequency of 1.92 H-2 s(-1) at 30 mV versus RHE. The Ru decorated CPs show comparable to higher catalytic activity than of Platinum (Pt) decorated CP also developed by ALD. The current representation of unfamiliar catalytic activities of Ru active centers developed by ALD, pave a bright and sustainable path for energy conversion reactions.