Publikační činnost Centra nanotechnologií / Publications of Nanotechnology Centre (9360)

Permanent URI for this collectionhttp://hdl.handle.net/10084/64663

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Centra nanotechnologií-CNT (9360) v časopisech registrovaných ve Web of Science od roku 2003 po současnost.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

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Now showing 1 - 20 out of 790 results

Transverse cracking signal characterization in CFRP laminates using modal acoustic emission and digital image correlation techniques
(Elsevier, 2024) Šofer, Michal; Cienciala, Jakub; Šofer, Pavel; Paška, Zbyněk; Fojtík, František; Fusek, Martin; Czernek, Pavel
The process of formation and subsequent propagation of transverse cracks in 90 degrees plies of carbon-fiber laminated composites was studied using modal acoustic emission approach and digital image correlation techniques. The results from modal acoustic emission approach, which included a newly developed processing tool for acoustic emission waveforms, provided information for identification and subsequent characterization or localization of signals originating from transverse cracking by analysis of the separated flexural and extensional Lamb wave modes in terms of their modal parameters. The digital image correlation method served as a verification tool of the acoustic emission data outputs in the terms of activity of significant localized events originating from the formation of the transverse crack in the 90oply. This made it possible to specify more locally the accompanying activity belonging to the formation or propagation of the magistral transverse crack. The manuscript also presents results related to the evolution of flexural/extensional wave modal parameters as the function of loading force for both [0/0/0/90]S and [90/0/0/0]S panels. It can be concluded that the detection of transverse cracks requires the need for applying a more complex acoustic emission data analysis methodology, while the standard parametric analysis, including the waveform peak frequency, is not sufficient. The presented methodology may serve as a basis for development of robust analysis tool capable of detecting the investigated phenomena.
Effect of milling atmosphere on stability and surface properties of ZnO/vermiculite hybrid nanocomposite powders
(Elsevier, 2024) Čech Barabaszová, Karla; Holešová, Sylva; Kupková, Jana; Hundáková, Marianna; Simha Martynková, Gražyna; Plesník, Lukáš; Basiaga, Marcin
The zinc acetate dihydrate and anhydrous zinc chloride were used as precursors for the sonochemical preparation of the zinc oxide/vermiculite and organically modified zinc oxide/vermiculite_chlorhexidine nanocomposite materials. The nanocomposites were mechanically processed via a high-energy ball milling for 30 min at 300 rpm using two types of atmospheres an air or a nitrogen. Changes in temperature and pressure inside the grinding vessels were measured during mechanical processing in an air atmosphere. The ZnO(Cl)/V_30/300 sample reached the highest pressure (1161 mbar) and temperature (30.3 degrees C) in the milling vessels and for the ZnO(ac)/V_CH_30/300 sample the highest temperature difference was measured at the beginning and at the end of the milling (7 degrees C). The phase transformation, chemical composition and particle size of the hybrid nanocomposite materials were investigated using X-ray diffraction method, Fourier-transform infrared spectroscopy, X-ray fluorescence spectroscopy, carbon phase analysis and particle size distribution analysis. Changes in morphology and particle arrangement were characterised using scanning electron microscopy. The effect of mechanical processing in a protective atmosphere on surface properties such as specific surface area, surface conductivity and zeta-potential were demonstrated in relation to the type of precursor used for the preparation of ZnO nanoparticles in the structure of hybrid nanocomposite materials.
Enhanced detection of heavy metal ions using Ag nanoparticles and single-walled carbon nanotubes within Cu-based metal-organic frameworks
(Elsevier, 2024) Bodkhe, Gajanan A.; More, Mayuri S.; Umar, Ahmad; Ibrahim, Ahmed A.; Siva, Subramanian; Deshmukh, Megha A.; Ingle, Nikesh N.; Gaikwad, Dhammajyot K.; Tsai, Meng-Lin; Hianik, Tibor; Kim, Myunghee; Shirsat, Mahendra D.
Heavy metal ions (HMIs) are major water pollutants, and their toxicity for humans is a great concern for scientists and environmentalists. They are harmful to health even at trace levels; therefore, identifying and removing heavy metals from water is critical. Herein, we report highly selective and sensitive multi-analyte detection of HMIs in water using an electrochemical sensor probe based on Ag nanoparticles and singlewalled carbon nanotubes incorporating copper benzene tri-carboxylate metal -organic frameworks (Ag/ SWNTs@CuBTC-MOFs). The materials were characterized using FTIR, XPS, XRD, and FE-SEM with EDX mapping, TEM, TG-DTA, BET surface area, CV, and EIS. The Ag/SWNTs@CuBTC-MOF electrochemical sensor was tested by differential pulse voltammetry over a pH range of 3 -10 for various HMIs. It shows high pH-dependent sensitivity towards Hg 2 + (pH-5.0), Ni 2 + (pH-7.0), and Fe 3 + (pH-10.0) ions and a limit of detection of 1.39 nM, 2.6 nM, and 3.03 nM, respectively. The fabricated sensor probe exhibits high selectivity, good linearity, and a limit of detection below the maximum contamination limit, as the US Environmental Protection Agency suggested.
A mononuclear Fe(III) complex showing thermally induced spin crossover and slow magnetic relaxation with reciprocating thermal behaviour
(Royal Society of Chemistry, 2024) Bridová, Terézia; Rajnák, Cyril; Titiš, Ján; Samoľová, Erika; Tran, Kevin; Malina, Ondřej; Bieńko, Alina; Renz, Franz; Gembický, Milan; Boča, Roman
AC susceptibility measurements of [Fe-III(L-5)(NCSe)] reveal a field supported slow magnetic relaxation. On cooling, the relaxation time of the high-frequency fraction decreases which is a sign of reciprocating thermal behaviour. The relaxation time for the low-frequency mode at T = 2.0 K is as high as tau(LF) = 2.0 s.
Pt single atoms on TiO2 can catalyze water oxidation in photoelectrochemical experiments
(American Chemical Society, 2024) Wu, Si-Ming; Wu, Lu; Denisov, Nikita; Baďura, Zdeněk; Zoppellaro, Giorgio; Yang, Xiao-Yu; Schmuki, Patrik
Photoelectrochemical water splitting on n-type semiconductors is highly dependent on catalysis of the rate-determining reaction of O-2 evolution. Conventionally, in electrochemistry and photoelectrochemistry O-2 evolution is catalyzed by metal oxide catalysts like IrO2 and RuO2, whereas noble metals such as Pt are considered unsuitable for this purpose. However, our study finds that Pt, in its single-atom form, exhibits exceptional cocatalytic properties for photoelectrochemical water oxidation on a TiO2 photoanode, in contrast to Pt in a nanoparticle form. The decoration of Pt single atoms onto TiO2 yields a remarkable current density of 5.89 mA cm(-2) at 1.23 V-RHE, surpassing bare TiO2 (or Pt nanoparticle decorated TiO2) by 2.52 times. Notably, this enhancement remains consistent over a wide pH range. By accompanying theoretical work, we assign this significant enhancement to an improved charge transfer and separation efficiency along with accelerated kinetics in the oxygen evolution reaction facilitated by the presence of Pt single atoms on the TiO2 surface.
Silver-loaded poly(vinyl alcohol)/polycaprolactone polymer scaffold as a biocompatible antibacterial system
(Springer Nature, 2024) Vilamová, Zuzana; Šimonová, Zuzana; Bednář, Jiří; Mikeš, Petr; Cieslar, Miroslav; Svoboda, Ladislav; Dvorský, Richard; Rosenbergová, Kateřina; Kratošová, Gabriela
A chronic nonhealing wound poses a significant risk for infection and subsequent health complications, potentially endangering the patient‘s well‑being. Therefore, effective wound dressings must meet several crucial criteria, including: (1) eliminating bacterial pathogen growth within the wound, (2) forming a barrier against airborne microbes, (3) promoting cell proliferation, (4) facilitating tissue repair. In this study, we synthesized 8 ± 3 nm Ag NP with maleic acid and incorporated them into an electrospun polycaprolactone (PCL) matrix with 1.6 and 3.4 µm fiber sizes. The Ag NPs were anchored to the matrix via electrospraying water‑soluble poly(vinyl) alcohol (PVA), reducing the average sphere size from 750 to 610 nm in the presence of Ag NPs. Increasing the electrospraying time of Ag NP‑treated PVA spheres demonstrated a more pronounced antibacterial effect. The resultant silver‑based material exhibited 100% inhibition of gram‑negative Escherichia coli and gram‑positive Staphylococcus aureus growth within 6 h while showing non‑cytotoxic effects on the Vero cell line. We mainly discuss the preparation method aspects of the membrane, its antibacterial properties, and cytotoxicity, suggesting that combining these processes holds promise for various medical applications.
A review on sustainable iron oxide nanoparticles: syntheses and applications in organic catalysis and environmental remediation
(Royal Society of Chemistry, 2024) Chaudhari, Dinesh S.; Upadhyay, Rohit P.; Shinde, Gajanan Y.; Gawande, Manoj B.; Filip, Jan; Varma, Rajender S.; Zbořil, Radek
Iron oxide nanoparticles have been intensively investigated owing to their huge potential as diagnostic, therapeutic, and drug-carrier agents in biomedicine, sorbents in environmental technologies, sensors of various inorganic and organic/biological substances, energy-generating and storing materials, and in assorted biotechnological and industrial processes involving microbiology, pigment industry, recording and magnetic media or (bio)catalysis. An eminent interest in exploring the realm of iron oxides is driven by their chemical and structural diversity, high abundance, low cost, non-toxicity, and broad portfolio of chemical procedures enabling their syntheses with desirable physicochemical features. The current review article centers its attention on the contemporary advancements in the field of catalysis and environmental technologies employing iron oxides in various chemical forms (e.g., hematite, magnetite, maghemite), sizes (∼10–100 nm), morphology characteristics (e.g., globular, needle-like), and nano archi tecture (e.g., nanoparticles, nanocomposites, core–shell structures). In particular, the catalytic appli cations of iron oxides and their hybrids are emphasized regarding their efficiency and selectivity in the coupling, oxidation, reduction, alkylation reactions, and Fischer–Tropsch synthesis. The deployment of iron oxides and their nanocomposites in environmental and water treatment technologies is also deliber ated with their roles as nanosorbents for heavy metals and organic pollutants, photocatalysts, and hetero geneous catalysts (e.g., hydrogen peroxide decomposition) for oxidative treatment of various contami nants. The associated challenges and potential progress in iron-oxide-based catalytic and environmental technologies are highlighted as well. Young chemists, researchers, and scientists could find this review useful in enhancing the usefulness of nano iron oxides in their investigations and developing sustainable methodologies.
Magneto-plasmonic “switch” device for magnetic field detection
(De Gruyter, 2024) Bsawmaii, Laure; Giraud, Pascal; El Haber, Gerges; Halagačka, Lukáš; Chatelon, Jean-Pierre; Jamon, Damien; Jourlin, Yves; Royer, François
This paper introduces a novel class of low-loss and cost-effective optical planar structures tailored for magnetic detection applications. These structures represent unconventional magneto-plasmonic devices specifically optimized for an 'optical switch' configuration. The structure consists of a 1D deep sinusoidal gold grating covered by a thin cobalt layer. In this unique arrangement, the excited plasmon induces a high-contrast switching phenomenon between the reflected free space intensity of specular (0th) and -1st diffracted orders, sensitive to any transverse magnetic fields applied to the cobalt layer. The use of these two distinct diffracted orders induces differential measurements, effectively mitigating common drift and perturbations. This innovative approach results in an enhanced detection sensitivity, showcasing the potential of these structures for advanced magnetic field sensing applications.
Enhancing photocatalytic g-C3N4/PVDF membranes through new insights into the preparation methods
(Elsevier, 2024) Vilamová, Zuzana; Sampaio, Maria J.; Svoboda, Ladislav; Bednář, Jiří; Šimonová, Zuzana; Dvorský, Richard; Silva, Cláudia G.; Faria, Joaquim L.
Fibrous membranes are crucial on the filtration of pollutants from air and water, but continued use can lead to a failure in effectiveness due to pollutant accumulation. To enhance durability, incorporating photocatalytic submicroparticles into these membranes appear as a solution. Here, we prepared a set of polyvinyl difluoride (PVDF) fibrous membranes modified with graphitic carbon nitride (g-C3N4) using three different methodologies. Their photocatalytic efficiency was investigated using phenol as model pollutant compound under visible light irradiation. Using g-C3N4 fibrous membranes modified by electrospinning blend a pseudo first-order kinetic constant (kapp) of 2.51 x 10-4 min-1 was observed for phenol degradation after 240 min reaction. Despite minimal particle adhesion the thermal treatment increased kapp to 5.41 x 10-4 min-1. The membranes prepared via chemical activation of PVDF exhibited the highest photocatalytic activity (kapp of 21.7 x 10-4 min-1). This superior activity was attributed to covalent bonds between PVDF and g-C3N4, allowing the formation of oxidative species.
Comparative study of photocatalysis with bulk and nanosheet graphitic carbon nitrides enhanced with silver
(Springer Nature, 2024) Michalska, Monika; Pavlovský, Jiří; Simha Martynková, Gražyna; Kratošová, Gabriela; Hornok, Viktória; Nagy, Peter B.; Novák, Vlastimil; Szabó, Tamás
The main goal of this research is to investigate the effectiveness of graphitic carbon nitride (g-C3N4, g-CN) in both bulk and nanosheet forms, which have been surface-modified with silver nanoparticles (Ag NPs), as photocatalysts for the degradation of acid orange 7 (AO7), a model dye. The photodegradation of AO7 dye molecules in water was used to test the potential photocatalytic properties of these powder materials under two different lamps with wavelengths of 368 nm (UV light) and 420 nm (VIS light). To produce Ag NPs (Ag content 0.5, 1.5, and 3 wt%) on the g-CN materials, a new synthesis route based on a wet and low-temperature method was proposed, eliminating the need for reducing agents. The photodegradation activity of the samples increased with increasing silver content, with the best photocatalytic performances achieved for bulk g-CN samples and nanosheet silver-modified samples (with the highest content of 3 wt% Ag) under UV light, i.e., more than 75% and 78%, respectively. The VIS-induced photocatalytic activity of both examined series was higher than that of UV. The highest activities of 92% and 98% were achieved for the 1.5% Ag-modified g-CN bulk and nanosheet materials. This research presents an innovative, affordable, and environmentally friendly chemical approach to synthesizing photocatalysts that can be used for degrading organic pollutants in wastewater treatment.
Overlap and rotate - a simple method for predicting out-of-plane and in-plane orientations of heteroepitaxial thin films
(Elsevier, 2024) Tokarský, Jonáš; Molek, Jonáš
The production of heteroepitaxial thin films is increasingly important due to their considerable utility in technical practice. This usability is determined by their specific physical and chemical properties influenced by the mutual crystallographic substrate-film orientation, both the out-of-plane and the in-plane. The possibility of predicting these orientations would reduce the time and financial burden of their experimental determination. This study shows how the out-of-plane and the in-plane orientation of heteroepitaxial film can be predicted by simply calculating number of overlapping atoms in a system of two overlapping crystallographic planes, one of which rotates relatively to the other. Coordinates of atoms in the crystallographic planes are taken from bulk structures, which contributes to the simplicity of the method. The average number of overlapping atoms (calculated from a 360° rotation) and the maximum number of overlapping atoms (including a corresponding angle) indicate the out-of-plane and the in-plane orientation, respectively. The method is tested on various substrate/film systems (SrTiO3/ZnO, Al2MgO4/ZnO, MgO/ZnO, MgO/CuO, Si/Al, MoS2/Au) and the results are compared with experimental data obtained from the literature. The good agreement with the experimental data shows this method to be reliable and sufficiently accurate for heteroepitaxial thin films.
Defect-mediated energy states in brookite nanorods: Implications for photochemical applications under ultraviolet and visible lkight
(American Chemical Society, 2024) Zollo, Alessia; Liao, Yu-Kai; Hejazi, S. M. Hossein; Shahrezaei, Mahdi; Daka, Mario; Salvadori, Enrico; Livraghi, Stefano; Naldoni, Alberto; Chiesa, Mario
The photochemical properties of brookite nanorods are systematically explored using light-induced electron-paramagnetic resonance (EPR) techniques at different wavelengths spanning the UV-vis region of the electromagnetic spectrum (355-650 nm). Under UV irradiation, electron-hole pairs are generated, leading to the stabilization of paramagnetic centers, primarily Ti3+ and O- species at the surface. Visible light irradiation at low temperature results in a unique pair of EPR signals, including electrons trapped at titanium cations and a distinct signal resonating at g = 2.004. The pair of signals disappears after annealing at room temperature, indicating that recombination pathways with trapped electrons are available. The chemical reactivity of the different photogenerated species is tested using electron and holes scavengers. While peculiar light-harvesting capabilities are observed for the brookite nanorods, experiments carried out in the presence of a hole scavenger indicate a limited potential for oxidative processes under visible light.
Graphene derivative-based ink advances inkjet printing technology for fabrication of electrochemical sensors and biosensors
(Elsevier, 2024) Nalepa, Martin-Alex; Panáček, David; Dědek, Ivan; Jakubec, Petr; Kupka, Vojtěch; Hrubý, Vítězslav; Petr, Martin; Otyepka, Michal
The field of biosensing would significantly benefit from a disruptive technology enabling flexible manufacturing of uniform electrodes. Inkjet printing holds promise for this, although realizing full electrode manufacturing with this technology remains challenging. We introduce a nitrogen-doped carboxylated graphene ink (NGA-ink) compatible with commercially available printing technologies. The water-based and additive-free NGA-ink was utilized to produce fully inkjet-printed electrodes (IPEs), which demonstrated successful electrochemical detection of the important neurotransmitter dopamine. The cost-effectiveness of NGA-ink combined with a total cost per electrode of $0.10 renders it a practical solution for customized electrode manufacturing. Furthermore, the high carboxyl group content of NGA-ink (13 wt%) presents opportunities for biomolecule immobilization, paving the way for the development of advanced state-of-the-art biosensors. This study highlights the potential of NGA inkjet-printed electrodes in revolutionizing sensor technology, offering an affordable, scalable alternative to conventional electrochemical systems.
Charge carrier recombination processes, intragap defect states, and photoluminescence mechanisms in stoichiometric and reduced TiO2 brookite nanorods: an interpretation scheme through in situ photoluminescence excitation spectroscopy in controlled environment
(Royal Society of Chemistry, 2024) Rega, Romina; Fioravanti, Ambra; Hejazi, S. M. Hossein; Shahrezaei, Mahdi; Kment, Štěpán; Maddalena, Pasqualino; Naldoni, Alberto; Lettieri, Stefano
The study of titanium dioxide (TiO2) in the brookite phase is gaining popularity as evidence has shown the efficient photocatalytic performance of this less investigated polymorph. It has been recently reported that defective anisotropic brookite TiO2 nanorods display remarkable substrate-specific reactivity towards alcohol photoreforming, with rates of hydrogen production significantly (18-fold) higher than those exhibited by anatase TiO2 nanoparticles. To elucidate the basic photo-physical mechanisms and peculiarities leading to such an improvement in the photoactive efficiency, we investigated the recombination processes of photoexcited charge carriers in both stoichiometric and reduced brookite nanorods via photoluminescence excitation spectroscopy in controlled environment. Through an investigation procedure employing both supragap and subgap excitation during successive exposure to oxidizing and reducing gaseous agents, we firstly obtained an interpretation scheme describing the main photoluminescence and charge recombination pathways in stoichiometric and reduced brookite, which includes information about the spatial and energetic position of the intragap states involved in photoluminescence mechanisms, and secondly identified a specific photoluminescence enhancement process occurring in only reduced brookite nanorods, which indicates the injection of a conduction band electron during ethanol photo-oxidation. The latter finding may shed light on the empirical evidence about the exceptional reactivity of reduced brookite nanorods toward the photo-oxidation of alcohols and the concomitant efficiency of photocatalytic hydrogen generation.
Unveiling the potential of covalent organic frameworks for energy storage: Developments, challenges, and future prospects
(Wiley, 2024) Dubey, Prashant; Shrivastav, Vishal; Boruah, Tribani; Zoppellaro, Giorgio; Zbořil, Radek; Bakandritsos, Aristides; Sundriyal, Shashank
Covalent organic frameworks (COFs) are porous structures emerging as promising electrode materials due to their high structural diversity, controlled and wide pore network, and amenability to chemical modifications. COFs are solely composed of periodically arranged organic molecules, resulting in lightweight materials. Their inherent properties, such as extended surface area and diverse framework topologies, along with their high proclivity to chemical modification, have positioned COFs as sophisticated materials in the realm of electrochemical energy storage (EES). The modular structure of COFs facilitates the integration of key functions such as redox-active moieties, fast charge diffusion channels, composite formation with conductive counterparts, and highly porous network for accommodating charged energy carriers, which can significantly enhance their electrochemical performance. However, ascribing intricate porosity and redox-active functionalities to a single COF structure, while maintaining long-term electrochemical stability, is challenging. Efforts to overcome these hurdles embrace strategies such as the implementation of reversible linkages for structural flexibility, stimuli-responsive functionalities, and incorporating chemical groups to promote the formation of COF heterostructures. This review focuses on the recent progress of COFs in EES devices, such as batteries and supercapacitors, through a meticulous exploration of the latest strategies aimed at optimizing COFs as advanced electrodes in future EES technologies.
Solvent controlled generation of spin active polarons in two-dimensional material under UV light irradiation
(American Chemical Society, 2024) Zoppellaro, Giorgio; Medveď, Miroslav; Hrubý, Vítězslav; Zbořil, Radek; Otyepka, Michal; Lazar, Petr
Polarons belong to a class of extensively studied quasiparticles that have found applications spanning diverse fields, including charge transport, colossal magnetoresistance, thermoelectricity, (multi)ferroism, optoelectronics, and photovoltaics. It is notable, though, that their interaction with the local environment has been overlooked so far. We report an unexpected phenomenon of the solvent-induced generation of polaronic spin active states in a two-dimensional (2D) material fluorographene under UV light. Furthermore, we present compelling evidence of the solvent-specific nature of this phenomenon. The generation of spin-active states is robust in acetone, moderate in benzene, and absent in cyclohexane. Continuous wave X-band electron paramagnetic resonance (EPR) spectroscopy experiments revealed a massive increase in the EPR signal for fluorographene dispersed in acetone under UV-light irradiation, while the system did not show any significant signal under dark conditions and without the solvent. The patterns appeared due to the generation of transient magnetic photoexcited states of polaronic character, which encompassed the net 1/2 spin moment detectable by EPR. Advanced ab initio calculations disclosed that polarons are plausibly formed at radical sites in fluorographene which interact strongly with acetone molecules in their vicinity. Additionally, we present a comprehensive scenario for multiplication of polaronic spin active species, highlighting the pivotal role of the photoinduced charge transfer from the solvent to the electrophilic radical centers in fluorographene. We believe that the solvent-tunable polaron formation with the use of UV light and an easily accessible 2D nanomaterial opens up a wide range of future applications, ranging from molecular sensing to magneto-optical devices.
Magnetically recyclable borane Lewis acid catalyst for hydrosilylation of imines and reductive amination of carbonyls
(Wiley, 2024) Saptal, Vitthal B.; Ranjan, Prabodh; Zbořil, Radek; Nowicki, Marek; Walkowiak, Jędrzej
Fluorinated arylborane-based Lewis acid catalysts have shown remarkable activity and serve as ideal examples of transition metal-free catalysts for diverse organic transformations. However, their homogeneous nature poses challenges in terms of recyclability and separation from reaction mixtures. This work presents an efficient technique for the heterogenization of boron Lewis acid catalysts by anchoring Piers’ borane to allyl-functionalized iron oxide. This catalyst demonstrates excellent activity in the hydrosilylation of imines and the reductive amination of carbonyls using various silanes as reducing agents under mild reaction conditions. The catalyst exhibits broad tolerance towards a wide range of functional substrates. Furthermore, it exhibits good recyclability and can be easily separated from the products using an external magnetic field. This work represents a significant advance in the development of sustainable heterogenous metal-free catalysts for organic transformations.
Precision engineering of nanorobots: Toward single atom decoration and defect control for enhanced microplastic capture
(Wiley, 2024) Jančík-Procházková, Anna; Kmentová, Hana; Ju, Xiaohui; Kment, Štěpán; Zbořil, Radek; Pumera, Martin
Nanorobots are being received with a great attention for their move-sense-and-act capabilities that often originate from catalytic decomposition of fuels. In the past decade, single-atom engineering has demonstrated exceptional efficiency in catalysis, energy-related technologies, and medicine. Here, a novel approach involving point defect engineering and the incorporation of platinum (Pt) single atoms and atomic level species onto the surface of titanium dioxide nanotubes (TiO2-NT)-based nanorobots is presented and its impact on the propulsion capabilities of the resulting nanorobots is investigated. The achievement of point defect engineering is realized through the annealing of TiO2-NT in a hydrogen atmosphere yielding to the point-defect decorated nanotube (TiO2-HNT) nanorobots. Subsequently, the atomic level Pt species decorated TiO2 nanotube (TiO2-SA-NT) nanorobots are achieved through a wet-chemical deposition process. Whereas TiO2-SA-NT nanorobots showed the highest negative photogravitaxis when irradiated with ultraviolet (UV) light, TiO2-HNT nanorobots reached the highest velocity calculated in 2D. Both TiO2-HNT and TiO2-SA-NT nanorobots demonstrated a pronounced affinity for microplastics, exhibiting the capability to irreversibly capture them. This pioneering approach utilizing point-defect and atomic level Pt species nanorobotics is anticipated to pave the way for highly efficient solutions in the remediation of nano- and microplastics and related environmental technologies.
Deciphering the role of nickel in electrochemical organic oxidation reactions
(Wiley, 2024) Ghosh, Suptish; Bagchi, Debabrata; Mondal, Indranil; Sontheimer, Tobias; Jagadeesh, Rajenahally V.; Menezes, Prashanth. W.
Organic oxidation reactions (OORs) powered by renewable energy sources are gaining importance as a favorable alternative to oxygen evolution reaction, with the promise of reducing the cell potential and enhancing the overall viability of the water electrolysis. This comprehensive review delves into the electrochemical oxidation of diverse organic compounds, including alcohols, aldehydes, amines, and urea, as well as biomass-derived renewable feedstocks such as hydroxymethylfurfural and glycerol. The key focus centers on the role of nickel (Ni)-based catalysts for these OORs. The unique redox activity and chemical nature of Ni have been proven instrumental for the sustainable and cost-effective oxidation of various organic molecules more efficiently and selectively. This review article discusses how strategic choices, such as the selection of foreign metals, intercalating species, vacancies, defects, and a secondary element (e.g. chalcogens and non-metals), contribute to tuning the electrochemical performances of a Ni-based (pre)catalyst for OORs. Moreover, this review provides insights into the active species in various reaction environments and further explores reaction mechanisms, to apparent phase changes of the catalyst with the most relevant examples. Finally, the review not only elucidates the limitations of the current approaches but also outlines potential avenues for future advancements in OOR.
Comprehensive study of antimicrobial polycaprolactone/clay nanocomposite films: Preparation, characterization, properties and degradation in simulated body fluid
(Wiley, 2024) Holešová, Sylva; Čech Barabaszová, Karla; Hundáková, Marianna; Kratošová, Gabriela; Kaloč, Václav; Joszko, Kamil; Gzik-Zroska, Bożena
Even though the biodegradability of polycaprolactone (PCL) and its nanocomposites is lower compared to other biodegradable polyesters, this property and good biocompatibility are used for development of materials for drug delivery with a long-term effect. We prepared novel PCL/clay nanocomposite films with antimicrobials chlorhexidine (CH) or octenidine (OCT) combined with ZnO anchored on vermiculite (VER). The intercalation of CH and OCT into the interlayer of VER/ZnOVER was confirmed by XRD, FTIR and SEM. The organically modified nanofillers compared to VER (−46.0 mV) or ZnOVER (−34.9 mV) showed a positive ζ-potential (+30.7 mV (VER_CH), +21.9 mV (VER_OCT), +24.6 mV (ZnOVER_CH)) indicating a relatively stable materials, except ZnOVER_OCT (+8.6 mV), which strongly agglomerated. Thin PCL/clay films were prepared by solvent casting method and the effect of used nanofillers on structural, thermal, mechanical and antimicrobial properties followed by degradation under hydrolytic conditions was studied. The results showed that presence of ZnO significantly decreases thermal and mechanical stability. The nanofillers with the higher hydrophilic character are responsible for the fastest degradation of PCL matrix. Films possessed high antimicrobial efficiency in long time intervals, hence these nanocomposites open new avenues for the possible application of such materials for the drug delivery with a long-term effect.

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