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 815 results

Elucidating the electrocatalytic activities of Pr-doped PtTiP nanocomposites for hydrogen evolution and methanol oxidation reactions
(Wiley, 2026) Basumatary, Padmini; Choi, Ji Hyeok; Sk, Mukkadar; Venkateswarlu, Sada; Misra, Biswajit; Thapa, Ranjit; Choi, Sun Hee; Jagadeesh, Rajenahally V.; Zbořil, Radek; Konwar, Dimpul; Yoon, Young Soo
Developing bifunctional electrocatalysts that combine high catalytic activity with long-term stability remains a major challenge in electrochemical energy conversions. Efficient hydrogen production via water splitting and methanol oxidation in direct methanol fuel cells are pivotal to realizing sustainable energy systems. However, few catalysts exhibit outstanding performance in both reactions. In this regard, we develop a praseodymium-doped platinum-titanium phosphide catalyst on modified nitrogen-doped multiwalled carbon nanotubes (PrPtTiP/N-MWCNT). Under acidic conditions (0.3 m H2SO4), PrPtTiP/N-MWCNT exhibits ultralow overpotentials of 8.2 and 12.2 mV at 10 and 100 mA cm- 2, respectively, which are substantially lower than those of PtP/N-MWCNT and commercial Pt/C. The developed catalyst maintains high activity at elevated current densities of up to 150 mA cm- 2 with minimal performance degradation. For methanol oxidation, PrPtTiP/N-MWCNT delivers a mass activity of 5.83 A mg-1 Pt, i.e., 3.3- and 8.3-fold enhancements over PtP/N-MWCNT and Pt/C, respectively. Comprehensive electrochemical, structural, and computational analyses confirm the excellent durability of the catalyst over 10,000 potential cycles and during prolonged chronoamperometric operation. Collectively, these results position PrPtTiP/N-MWCNT as a robust and highly active bifunctional electrocatalyst for hydrogen evolution and methanol oxidation in acidic environments.
Synergistic light-thermal-mass engineering of metal-coordinated covalent organic framework membranes for water purification
(Wiley, 2026) Sheng, Kai; Xiao, Zijie; Meng, Jiakun; Tian, Miaomiao; Cao, Xueli; Hou, Jingwei; Sun, Shi-Peng; Zhang, Yatao; Zhu, Junyong; Van der Bruggen, Bart
Membrane-based photothermal evaporation and separation offer a sustainable solution for both clean water access and environmental remediation. Covalent organic framework (COF) membranes are highly attractive due to their ordered porosity and chemical tunability, yet efficient light-to-heat-to-mass conversion at the interface remains challenging. Here we present a synergistic light-thermal-mass engineering strategy to overcome this limitation by utilizing cation-coordinated COF membranes. Through interfacial polymerization, we synthesized a photothermal COF with abundant nitrogen and oxygen chelating sites, followed by coordination with various divalent cations. Experimental and simulation results reveal that atomic dispersion of Co centers within a COF layer facilitates steeper interfacial gradients under one-sun irradiation, driving intensified buoyant convection to enhance mass transport and evaporation. The representative cobalt-COF (Co-COF) membrane achieves an extraordinary 99.996% ion removal, which meets stringent WHO standards. Complementary frontier molecular orbital analysis indicates substantial shifts in the HOMO and LUMO energy levels, resulting in a pronounced near-infrared redshift of the optical absorption edge. This substantially increases the photon budget for highly efficient photothermal and photocatalytic processes, conferring a high removal efficiency of volatile organic contaminants. This work underscores how precise metal ion coordination within COF structures significantly boosts both photothermal and photocatalytic efficiencies for sustainable water treatment.
Nanomaterial-based inkjet printing for electrochemical sensing
(Wiley, 2026) Panáček, David; Urban, Massimo; Silvestri, Alessandro; Dědek, Ivan; Nalepa, Martin-Alex; Merkoçi, Arben; Prato, Maurizio; Otyepka, Michal
Inkjet printing (IJP) has emerged as a transformative technology for printed and flexible electronics, redefining electrode engineering for (bio)chemical sensing. It enables maskless, picoliter-scale, additive deposition with high spatial precision, uniformity, and material efficiency. We provide a comprehensive overview of IJP as both a fabrication and post-fabrication functionalization platform for electrochemical working electrodes and fully printed devices. We integrate advances in ink formulation, jetting behavior, and substrate interactions with performance metrics such as layer thickness, roughness, electrochemical surface area, sensitivity, detection limit, and reproducibility. Comparative analyses with drop-casting and screen-printing highlight IJP's advantages in reproducibility, scalability, and material economy. Particular emphasis is placed on nanomaterial- and bioink-based systems, including carbon nanomaterials, MXenes, and hybrid inks, where controlled deposition governs electrode functionality. We also discuss emerging opportunities in hybrid architectures, reactive printing, and sustainable approaches using biodegradable substrates and water-based inks. Finally, we outline a roadmap toward automated, digitally controlled, and environmentally responsible manufacturing of customizable sensors for wearable, biomedical, food, and environmental applications. Collectively, these developments position inkjet printing as an enabling framework for the next generation of intelligent, reproducible, and sustainable sensing technologies.
Entropy-driven disordered surface formation with durable anti-water stability for ultra-stable layered oxide cathodes in sodium-ion batteries
(Elsevier, 2026) Wang, Jiaqi; Zhou, Junhua; Shi, Qitao; Zhang, Cheng; Wang, Zhipeng; Bachmatiuk, Alicja; Shen, Yanbin; Choi, Jinho; Yang, Ruizhi; Rümmeli, Mark H.
Conventional layered oxide cathodes for sodium-ion batteries (SIBs) suffer from severe capacity degradation due to crystalline surface reactivity, which triggers parasitic reactions with ambient H2O/O-2, leading to surface corrosion and bulk structural collapse. Herein, we introduce a high-entropy engineering strategy that designs a self-protective cathode, Na0.8Mg0.1Zn0.1Cu0.1Fe0.1Mn0.6O2 (HEO). This material spontaneously forms an entropy-stabilized amorphous surface coating with an ultralow formation energy of 0.16 eV. The coating acts as a kinetic barrier, raising the activation energy for detrimental H2O/O2 reactions by 160 % compared to a low-entropy counterpart (Na0.8Mg0.2Mn0.8O2). The synergy between entropy stabilization and surface amorphization delivers exceptional environmental robustness. After 90 days of water exposure, HEO retains 98 % of its initial capacity, and 99 % capacity retention over 100 cycles, surpassing state-of-the-art layered cathodes in cycling stability. This work establishes a universal framework for designing air/water-resilient cathodes, with immediate implications for scalable manufacturing and long-term storage stability of SIB systems.
Photoexcited species localize on solvent-accessible fluorophore-rich domains inside carbon dots
(Elsevier, 2026) Langer, Michal; Zdražil, Lukáš; Rogach, Andrey L.; Osella, Silvio; Otyepka, Michal
Understanding the optical properties of luminescent carbon dots (CDs) at the electronic level is essential for engineering their light-responsive behavior. The localization of photoexcited species and the pathways of their de-excitation govern CD performance in sensing, bioimaging, and emerging photocatalytic applications. Yet, the underlying mechanisms remain unresolved. Here, we combine multiscale simulations with experiments on CDs synthesized from citric acid (CA) and ethylenediamine (EDA), precursors capable of forming the molecular fluorophore 5-oxo-1,2,3,5-tetrahydroimidazo[1,2-alpha]pyridine-7-carboxylic acid (IPCA). All-atom molecular dynamics simulations in water reveal that CA-EDA oligomeric condensation products containing IPCA units spontaneously assemble into dynamic similar to 2 nm nanoparticles with amorphous internal structures and stacked domains reminiscent of those observed in transmission electron microscopy images of CDs. Time-dependent density functional theory (TD-DFT) calculations show that photoexcited carriers are generated in these domains and remain spatially distributed, not confined to the CD core. Quenching experiments with Hg2+ confirm their accessibility to the environment. We therefore propose a structural model of fluorophore-rich domains embedded in an amorphous carbonaceous matrix, explaining the quasi-spherical morphology and characteristic blue photoluminescence. This model provides a mechanistic basis for fluorescence sensing and photocatalysis and establishes a framework for rational design of CDs with tailored photophysical and catalytic properties.
Cross-coupling reactions with nickel, visible light, and tert-butylamine as a bifunctional additive
(American Chemical Society, 2024) Düker, Jonas; Philipp, Maximilian; Lentner, Thomas; Cadge, Jamie A.; Lavarda, João E.A.; Gschwind, Ruth M.; Sigman, Matthew S.; Ghosh, Indrajit; König, Burkhard
Transition metal catalysis is crucial for the synthesis of complex molecules, with ligands and bases playing a pivotal role in optimizing cross-coupling reactions. Despite advancements in ligand design and base selection, achieving effective synergy between these components remains challenging. We present here a general approach to nickel-catalyzed photoredox reactions employing tert-butylamine as a cost-effective bifunctional additive, acting as the base and ligand. This method proves effective for C-O and C-N bond-forming reactions with a diverse array of nucleophiles, including phenols, aliphatic alcohols, anilines, sulfonamides, sulfoximines, and imines. Notably, the protocol demonstrates significant applicability in biomolecule derivatization and facilitates sequential one-pot functionalizations. Spectroscopic investigations revealed the robustness of the dynamic catalytic system, while elucidation of structure-reactivity relationships demonstrated how computed molecular properties of both the nucleophile and electrophile correlated to reaction performance, providing a foundation for effective reaction outcome prediction.
Overcoming nanosilver resistance: Resensitizing bacteria and targeting evolutionary mechanisms
(American Chemical Society, 2024) Sun, Rui; Cui, Yueting; Wu, Yining; Gao, Meng; Xue, Shiyuan; Li, Ruibin; Zbořil, Radek; Zhang, Chengdong
The rapid spread of antimicrobial resistance poses a critical threat to global health and the environment. Antimicrobial nanomaterials, including silver nanoparticles (AgNPs), are being explored as innovative solutions; however, the emergence of nanoresistance challenges their effectiveness. Understanding resistance mechanisms is essential for developing antievolutionary strategies. AgNPs exhibit diverse resistance mechanisms, and our findings reveal a dynamic transition between these mechanisms: from flagellin-mediated AgNP precipitation (state I) to activation of the copper efflux pump (CusCFBA) system (state II). We designed targeted physicochemical interventions to counteract these mechanisms. Energy supply blocking was effective for state I, while for state II, neutralizing intracellular acidic pH significantly reduced resistance. These strategies reduced nanoresistance/tolerance by up to 10,000-fold. Additionally, resistance evolution can be completely halted by disrupting the energy supply using carbonyl cyanide 3-chlorophenylhydrazone and overactivating sigma E, one of the key envelope stress regulators that govern resistance transitions. Our findings provide practical strategies to overcome nanoresistance, offering a groundbreaking approach to enhance nanoantimicrobials' efficacy in medical therapies and combat resistance evolution.
Appropriate agro-environmental strategy for ZnO-nanoparticle foliar application on soybean
(Polskie Towarzystwo Gleboznawcze, 2024) Ernst, Dávid; Kolenčík, Marek; Straka, Viktor; Šebesta, Martin; Ďurišová, Ľuba; Tomovičová, Lenka; Kratošová, Gabriela; Ravza, Ivan; Žitniak Čurná, Veronika; Černý, Ivan; Qian, Yu; Gažo, Ján; Ducsay, Ladislav; Polláková, Nora; Juriga, Martin
Although the nanoparticle (NP) utilization in agronomy is currently orientated to intensify crop yield, the potential negative effects on soil and plant reproductive organs, including effects on pollen are largely absent in the literature. For this reason, our study was set to evaluate the impact of ZnO nanoparticles (ZnO-NPs) on the selective properties of Fluvisol, on the direct microbial activity and zinc (Zn) phytoavailability, and crop yield after their foliar application on soybean [ Glycine max (L.) Merril] under field conditions. Additionally, the potential hazardous impact to plant reproductive structures was evaluated, focusing on the agronomically and environmentally sensitive biomarker - pollen viability. The soil biological activity was evaluated through microbial respiration while Zn phytoavailability was determined using reaction agents with nutrients analysis conducted through flame atomic absorption spectroscopy (F-AAS). Pollen viability was evaluated using the iodine potassium iodide (IPI) test. The experiments were carried out at an experimental site of the Faculty of Agrobiology and Food Resources (FAFR) at the Slovak University of Agriculture (SUA) in Nitra, located in Central Europe, during the 2023 vegetation season. Depending on increasing concentrations of ZnO-NPs through order of 1.4, 14, and 140 mg L-1, revealed no harmful effect on soil microbial activity or hazardous Zn accumulation in the context of its Fluvisol-phytoavailable distribution compared to NPs-free control. A positive impact on soybean pollen viability was observed at all applied ZnO-NP concentrations compared to the NP-free control. The highest pollen viability, reaching up to 97.04%, was achieved at a concentration of 1.4 mg L-1, and, subsequently, it slightly decreased with increasing concentrations of ZnO-NPs. Moreover, the application of ZnO-NPs had a positive impact on soybean weight of thousand seeds and seed yield, where it's the highest concentration was the most effective. Thus, our results directly demonstrate the positive efficiency on selective properties of soil and reproductive structure - pollen, where ZnO-NP spray application acted positively and stimulatingly. Additionally, ZnO-NPs had positive impact on weight of thousand seeds (TSW) and seed yield. Therefore, the use of nanoparticles in foliar applications could be considered as kind of novelty in precision and sustainable agriculture.
Densely carboxylated graphene for synthesis of high-performing NASICON cathodes for Na-ion batteries
(American Chemical Society, 2026) Obraztsov, Ievgen; Cymann-Sachajdak, Anita; Bruniecka, Kamila; Madajski, Piotr; Šedajová, Veronika; Trykowski, Grzegorz; Bakandritsos, Aristides; Wilamowska-Zawłocka, Monika
Sodium-ion batteries are emerging as a promising alternative to lithium-ion technology due to the abundance and low cost of sodium. Among the cathode candidates, Na3V2(PO4)3 (NVP) with a NASICON framework and its analogues offer a high operating voltage and excellent structural stability. However, their practical use is limited by poor electronic conductivity, a low active material fraction, and trade-offs in terms of morphology and tap density. Here, we report a simple synthesis strategy that employs densely carboxylated graphene, graphene acid (GA), as a multifunctional additive. GA acts simultaneously as a chelating agent, pH regulator, and in situ-formed carbon shell prior to calcination. GA allows the efficient reduction of V5+ to electrochemically active V3+, phase-pure NVP formation, and the growth of a thin, conformal carbon shell strongly anchored to NVP particles. The resulting electrodes contain 85 wt % active material while maintaining outstanding charge-transfer kinetics. The optimized NVP@GA cathode delivers an excellent rate performance up to 15 A gEM -1 (151 C), retaining 65.4% of the theoretical capacity of NVP, and stable cycling. This approach provides a versatile route for tailoring NASICON cathodes and can be extended to other phosphate-based systems for high-power sodium-ion batteries.
Enhancing early osteogenic differentiation on Ti6Al4V implants via MAO coatings doped with strontium and calcium
(Elsevier, 2026) Gabor, Roman; Doubková, Martina; Cvrček, Ladislav; Filová, Elena; Malic, Marina; Mašek, Karel; Hlinka, Josef; Martynková, Gražyna Simha; Walter, Jan; Večeř, Marek; Seidlerová, Jana; Tokarčíková, Michaela; Bačáková, Lucie
Titanium alloys such as Ti6Al4V are widely used in orthopaedic implants due to their excellent mechanical and corrosion-resistant properties. However, insufficient early-stage osseointegration remains a critical challenge, often leading to implant loosening and failure. To overcome this issue, bone implant design and surface modification increasingly focus on incorporating bioactive elements. This study explores the enhancement of osseointegration through micro-arc oxidation (MAO) surface modification of Ti6Al4V, incorporating bioactive strontium (Sr) and calcium (Ca) ions. Two surface pretreatments - polishing (P) or shot-blasting (B) - were applied prior to MAO to generate coatings with distinct topographies and compositions: TAV(P), TAV(P)-Sr, TAV (P)-Sr-Ca, TAV(B), TAV(B)-Sr, and TAV(B)-Sr-Ca. Surface characterization of the resulting oxide layers confirmed the incorporation of Sr, Ca, and phosphate ions, with Sr releasing continuously over 60 days. Wear resistance analysis revealed the highest coefficient of friction for the TAV(P)-Sr coatings and the lowest values for TAV(B)-Sr. Surface modification by blasting led to reduced corrosion resistance in the TAV(B), TAV(B)-Sr, and TAV(B)-Sr-Ca samples. Nevertheless, enhanced corrosion resistance was observed in all samples modified with Sr and Sr+Ca. In vitro analyses using human bone marrow-derived mesenchymal stromal cells (hBMSCs) demonstrated excellent biocompatibility of all coatings. Notably, Sr-doped and especially Sr-Ca-doped surfaces significantly enhanced early osteogenic differentiation, as evidenced by increased alkaline phosphatase activity and type I collagen deposition. These findings highlight the synergistic effects of surface topography and Sr-Ca ion doping in promoting early-stage osseointegration, offering a promising strategy for improving the performance of titanium-based bone implants, particularly in patients with compromised bone healing.
Oxidative pyrolysis of alkali lignin using nitrogen functionalized graphene oxide-cerium oxide nanocatalysts: Mechanistic insights thorough density functional theory
(Elsevier, 2025) Kumar, Shivam; Kumar, Pankaj; Kumar, Navneet; Park, Jinsub; Srivastava, Vimal Chandra
In this study, a functionalized graphene oxide-cerium oxide nanocatalysts (FGCe) with varying graphene oxide (GO) contents were prepared using an in-situ reflux method. The prepared nanocatalysts showcased improvement in the crystallinity and BET surface area values with increasing GO contents. The efficacies of prepared catalysts were investigated towards oxidative pyrolysis of alkali lignin in an ethanol-water system. Among various nanocatalyst samples, the best lignin conversion (93 %) and bio-oil yield (86 %) were achieved using 50 mg FGCe nanocatalyst (0.5 wt% GO) at 423 K and 60 min. GC-MS and 1HNMR analyses were used to identify significant lignin conversion products, including 2-pentanone-4-hydroxy-4-methyl, 2-methoxyphenol, nonylcyclopropane, vanillin, apocynin, homovanollic acid, and benzoic acid. Kinetic studies revealed that the activation energy for lignin conversion was 24.36 kJ/mol at 423 K. Mechanistic investigations by density functional theory analysis revealed that the lignin breakdown occurred at oxygen bonds producing aromatic.
New approach to assessing nanofiber-based air filters efficiency across variable airflow velocities
(Elsevier, 2025) Dvorský, Richard; Bednář, Jiří; Vilamová, Zuzana; Šimonová, Zuzana; Svoboda, Ladislav
Filtration is a fundamental method in aerosol science for separating unwanted particles, mainly through air filters. Since the onset of the SARS-CoV-2 pandemic in 2019, there has been an increased demand for high- efficiency, low-cost nanofiber-based respirators capable of filtering particles within the size range of viruses and bacteria. The quality factor QF is the critical parameter for evaluating these respirators' practical effectiveness. QF integrates filtration efficiency with a tolerable pressure drop for the respiratory process. Typically, this pressure drop is reported as a function of the flow rate for a given respirator. However, the physical mechanism of filtration is governed by the mean frontal airflow velocity, which depends not only on the flow rate but also on the membrane area, a parameter often unknown in practical applications. The aerosol flow rate influences filtration efficiency and pressure drop through the membrane, yet a comprehensive physical description of this process has been lacking. Therefore, we developed a mathematical-physical model for filtration using a nanofibrous membrane that accounts for all relevant physical mechanisms. This model provides a more accurate definition of the quality factor. Our findings indicate that filtration efficiency does not reach 100 %, even at near-zero air velocities, and that efficiency approaches an asymptotic plateau at high velocities. When fitted to experimental data from various filters using a three-parameters approach, the model's predictions show strong agreement, particularly within the central region of the uncertainty band.
Fibrous PVDF membranes modified by anchored g-C3N4@GO composite with enhanced photocatalytic activity
(Elsevier, 2024) Vilamová, Zuzana; Czernek, Pavel; Zágora, Jakub; Svoboda, Ladislav; Bednář, Jiří; Šimonová, Zuzana; Plachá, Daniela; Dvorský, Richard
Recently, the development of fibrous membranes for pollutant filtration from air or water has been a topic of great interest. However, these filters' high and rapid fouling has limited their use. In response, we have prepared photocatalytic active membranes that harness the synergic effect between graphene oxide (GO) and graphitic carbon nitride (g-C3N4). The resulting composite demonstrated the highest photocatalytic activity (k(obs) = 88 x 10(-3) min(-1)). This g-C3N4@GO composite was then carefully deposited on/in an electrospun polyvinyl difluoride (PVDF) fibrous membrane. The reproducible results of the chemical bonding of the composite to the PVDF matrix were evident during photocatalytic experiments after ten Rhodamine B (Rh B) photocatalytic degradation cycles. Importantly, the fiber structure analysis post-reaction did not reveal any fiber cracks or void formation defects, indicating the excellent chemical stability of the PVDF fibrous matrix. This research offers a promising, sustainable, eco-friendly, and efficient solution for removing pollutants from different environments, inspiring further exploration and development in this field.
Improved ammonia synthesis and energy output from zinc-nitrate batteries by spin-state regulation in perovskite oxides
(American Chemical Society, 2025) Guo, Hele; Zhou, Yazhou; Chu, Kaibin; Cao, Xueying; Qin, Jingjing; Zhang, Nan; Roeffaers, Maarten B. J.; Zbořil, Radek; Hofkens, Johan; Müllen, Klaus; Lai, Feili; Liu, Tianxi
Electrocatalytic nitrate reduction to ammonia (eNRA) is a promising route toward environmental sustainability and clean energy. However, its efficiency is often limited by the slow conversion of intermediates due to spin-forbidden processes. Here, we introduce a novel A-site high-entropy strategy to develop a new perovskite oxide (La0.2Pr0.2Nd0.2Ba0.2Sr0.2)CoO3-delta (LPNBSC) for eNRA. The LPNBSC possesses a higher concentration of high-spin (HS) cobalt-active centers, resulting from an increased concentration of [CoO5] structural motifs compared to conventional LaCoO3. Consequently, this material exhibits a significantly improved electrocatalytic performance toward ammonia (NH3) production, resulting in a 3-fold increase in yield rate (129 mu mol h-1 mgcat. -1) and a 2-fold increase in Faradaic efficiency (FE, 76%) compared to LaCoO3 at the optimal potential. Furthermore, the LPNBSC-based Zn-nitrate battery reaches a maximum FE of 82% and an NH3 yield rate of 57 mu mol h-1 cm-2. Density functional theory calculations reveal that A-site high-entropy management in perovskites facilitates nitrate activation and potentially optimizes the thermodynamic rate-determining step of the eNRA process, namely, *HNO3 + H+ + e- -> *NO2 + H2O. This work presents an efficient concept for modulating the spin state of the B-site metal in perovskites and offers valuable insights for the design of high-performance eNRA catalysts.
Multi-molecular logic framework based on Morse code, ASCII logic, and Beale's cipher for advanced crypto-steganography
(Wiley, 2026) Mattath, Mohamed Nabeel; Lu, Yingying; Parambil, Ajith Manayil; Gao, Yan; Yao, Tian-Ming; Li, Jing-Jing; Zang, Rui-Min; Hu, Song; Shi, Shuo
Molecular information coding (MIC) involves biomolecules to encrypt and transmit messages, remains in its early stages of development. This work presents a versatile molecular integration framework and a proof-of-concept multi-level security system that combines Morse code, ASCII code, and Beale's cipher through molecular logic computing, using a molecular dye-oligonucleotide platform (single-stranded DNA, duplex DNA, stem-loop, and G-quadruplex (G-4) structures). This study demonstrates the integration of nanotechnology with crypto-steganographic methods to visualize and decipher codes, embedding elementary logic operations into molecular signal transduction. Additionally, a graphical user interface (GUI) is developed for classifying elementary logic gates using a decision tree algorithm, providing researchers with an accessible tool for rapid prediction. The Morse code-mediated strategy enables static key generation using dots, dashes, and intervals, and dynamic key generation through a polyalphabetic cipher framework. In parallel, ASCII-based logic gate operations facilitate multi-key decryption of decimal values to recover hidden information. Furthermore, a multilayered hybrid cryptographic technique combining Beale's cipher with Morse code implemented via a pangramic codebook, establishes an exceptionally resistant system against brute-force attacks. These methods provide insights into the evolution of communication and highlight the importance of encryption without relying on highly complex materials or sophisticated instruments.
Development of iron-based single atom materials for general and efficient synthesis of amines
(Wiley, 2024) Ma, Zhuang; Kuloor, Chakreshwara; Kreyenschulte, Carsten; Bartling, Stephan; Malina, Ondřej; Haumann, Michael; Menezes, Prashanth W.; Zbořil, Radek; Beller, Matthias; Jagadeesh, Rajenahally V.
Earth abundant metal-based heterogeneous catalysts with highly active and at the same time stable isolated metal sites constitute a key factor for the advancement of sustainable and cost-effective chemical synthesis. In particular, the development of more practical, and durable iron-based materials is of central interest for organic synthesis, especially for the preparation of chemical products related to life science applications. Here, we report the preparation of Fe-single atom catalysts (Fe-SACs) entrapped in N-doped mesoporous carbon support with unprecedented potential in the preparation of different kinds of amines, which represent privileged class of organic compounds and find increasing application in daily life. The optimal Fe-SACs allow for the reductive amination of a broad range of aldehydes and ketones with ammonia and amines to produce diverse primary, secondary, and tertiary amines including N-methylated products as well as drugs, agrochemicals, and other biomolecules (amino acid esters and amides) utilizing green hydrogen.
Real time tracking of nanoconfined water-assisted ion transfer in functionalized graphene derivatives supercapacitor electrodes
(Wiley, 2024) Padinjareveetil, Akshay Kumar K.; Pykal, Martin; Bakandritsos, Aristides; Zbořil, Radek; Otyepka, Michal; Pumera, Martin
Water molecules confined in nanoscale spaces of 2D graphene layers have fascinated researchers worldwide for the past several years, especially in the context of energy storage applications. The water molecules exchanged along with ions during the electrochemical process can aid in wetting and stabilizing the layered materials resulting in an anomalous enhancement in the performance of supercapacitor electrodes. Engineering of 2D carbon electrode materials with various functionalities (oxygen (& horbar;O), fluorine (& horbar;F), nitrile (& horbar;C equivalent to N), carboxylic (& horbar;COOH), carbonyl (& horbar;C & boxH;O), nitrogen (& horbar;N)) can alter the ion/water organization in graphene derivatives, and eventually their inherent ion storage ability. Thus, in the current study, a comparative set of functionalized graphene derivatives-fluorine-doped cyanographene (G-F-CN), cyanographene (G-CN), graphene acid (G-COOH), oxidized graphene acid (G-COOH (O)) and nitrogen superdoped graphene (G-N) is systematically evaluated toward charge storage in various aqueous-based electrolyte systems. Differences in functionalization on graphene derivatives influence the electrochemical properties, and the real-time mass exchange during the electrochemical process is monitored by electrochemical quartz crystal microbalance (EQCM). Electrogravimetric assessment revealed that oxidized 2D acid derivatives (G-COOH (O)) are shown to exhibit high ion storage performance along with maximum water transfer during the electrochemical process. The complex understanding of the processes gained during supercapacitor electrode charging in aqueous electrolytes paves the way toward the rational utilization of graphene derivatives in forefront energy storage applications.
Thermodynamic and multi-step kinetic analysis of slow pyrolysis of natural rubber-silanised cellulose composites with 30-55 phr filler content
(Elsevier, 2026) Dobrovská, Jana; Skalková, Petra; Iudina, Elizaveta; Holešová, Sylva; Kawuloková, Monika; Janík, Róbert
Pyrolysis is a promising thermochemical process for waste reduction and energy recovery. Natural rubber (NR) composites filled with 30, 45, and 55 phr silanised cellulose (CELS) were prepared and characterised by SEM and FTIR techniques. Thermogravimetric curves for heating rates of 2, 4, 6, 8, 10, and 20 °C·min−1 were measured in an inert gas. Kinetic parameters were determined by isoconversional kinetic analysis using the Friedman model-free method and a model-based method. By applying the generalised master plot method, it was found that the pyrolysis process follows an autocatalytic mechanism involving two kinetically independent, parallel pathways, each pathway consisting of two sequential steps. The results show that silanisation of cellulose has a positive effect on composite thermal stability, but only up to a specific content of CELS. At high loadings, the resulting silica-rich ash can act as a solid acid catalyst, accelerating secondary cracking reactions during pyrolysis. Innovative approaches for determining the formal thermodynamic parameters have been presented. The first method is based on the Eyring equation and the knowledge of Eα = f(α) and Aα = f(α) from the model-free method, providing the thermodynamic parameters as a function of the entire conversion range, α. The second method is based on the results of model-based kinetic analysis. The method makes it possible to determine these parameters for individual steps of a multi-step model and, thus, to compare the energy demand, spontaneity, and change in disorder of the system in the transition state for these steps.
Nickel-catalyzed reductive hydrolysis of nitriles to alcohols
(Wiley, 2025) Kuloor, Chakreshwara; Goyal, Vishakha; Zbořil, Radek; Beller, Mathias; Jagadeesh, Rajenahally V.
Nitriles are an abundant class of compounds that are widely used as versatile feedstocks to produce variouschemicals including pharmaceuticals, and agrochemicals as well as materials. Here we report Ni-catalyzed reductivehydrolysis of nitriles to alcohols in the presence of molecular hydrogen. This conversion likely occurs in a dominoreaction sequence that first involves the hydrogenation of nitrile to primary imine, then the hydrolysis of imine, andsubsequent deamination to the aldehyde, which is finally hydrogenated to the desired alcohol. Crucial for this reductivehydrolysis process is the commercially available triphos-ligated Ni-complex that enables highly efficient and selectivetransformation of aromatic, heterocyclic, and aliphatic nitriles including fatty nitriles to prepare functionalized primaryalcohols. Further, the synthetic applicability of this Ni-based protocol is presented for the selective conversion of nitrileto alcoholic group in structurally diverse and complex drug molecules as well as agrochemicals. The resulting products,alcohols are indispensable chemicals commonly used in organic synthesis and life sciences as well as material and energytechnologies.
Roman cement mortar prepared by a multi-stage mixing process
(Consejo Superior de Investigaciones Científicas, 2025) Daňková, Jana; Mec, Pavel; Gabor, Roman; Bujdoš, David; Majstríková, Tereza; Valentová, Adéla; Šafrata, Jiří
Roman cement is the predecessor to modern Portland cement. Nowadays, it is a very promising product with lower CO2 emissions, frequently used to restore historical objects. However, there are still many practical problems as a setting that can be affected in several ways. One possibility is the multistage mixing of fresh mortar, a practical historical method that has not yet been scientifically investigated. This article presents an experimental study investigating the effect of multistage mixing on the properties of fresh and hardened mortar. The properties and structure of the mortar were compared with a reference mortar (retardened by citric acid). Multistage mixing affects fresh mortars with optimal consistency and a workability time of 120 minutes. The influence of mixing on the hydration process and structural formation is characterized by isothermal calorimetry and SEM. Comparison of reference and modified mixing mortars exhibits differences in hydration process, structure, and initial strength, but no significant effect at 90 days strength.

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