Carbon Black Research Articles

Preparing a binder-free cathode composed of NMC811/sulfonated reduced graphene oxide sheets/carbon black via in-situ electrophoretic deposition to enhance cyclability of Li-ion batteries

Disruption in the restacking of the graphene present in the electrodes could hamper the reduction in the conductivity and also the surface area, which may be a good reason why graphene has not yet performed as predicted. In this research, we employed the scalable electrophoretic deposition (EPD) procedure to make instantly a binder-free Li-ion battery cathode, consisting of LiNi0.8Mn0.1Co0.1O2 (NMC811), sulfonated reduced graphene oxide (SRGO) sheets, and carbon black (CB) particles. The EPD process caused a squeezing force, which not only wrapped the SRGO sheets around the NMC811 nanoparticles, but also inserted the CB particles into the composite in an electrostatically stabilized combination. As evidenced by the electrochemical measurements, the binder-free NMC/SRGO/CB electrode manifested better cycling performance at the current density of 0.2 C, where this electrode delivered discharge capacities of 170.3 and 143.7 mAh g−1, respectively, at the 1st and 200th cycle compared to discharge capacities of 162.3 and 122.6 mAh g−1 acquired for the NMC/SRGO electrode. The excellent cycle stability and rate capability of the optimized binder-free NMC/SRGO/CB cathode can be attributed to withstanding the volume expansion of the active particles during cycling due to wrapping graphene sheets, inhibition of the restacking of graphene sheets by sulfonated groups and CB spacers, electrostatic interaction between sulfonated groups and lithium ions, and efficient electrolyte infiltration by ion and electron conductive channels in the binder-free cathode structure.

Multifunctional and high-performance electrothermal films based on carbon black/Ag nanowires/graphene composites

Fabricating high-conductive composites and constructing highly conductive networks are crucial for high-performance electrothermal film. In this study, an Ag nanowires/graphene (Ag/G) composite synthesized by liquid-phase exfoliation and in-situ photoreduction is mixed with carbon black (CB) to form a composite conductive ink, and a CB/Ag/G composite electrothermal film with a point-line-plane three-dimensional microstructure is obtained via blade coating process. Both the addition of Ag nanowires and a subsequent compression rolling treatment induce the establishment of the effective conductive network in the film, endowing it with an outstanding conductivity of 399.4 S cm−1. The film reaches a Ts of 204 °C with an input voltage of 3.0 V, and is successfully applied in water heating and de-icing, demonstrating its extraordinary electrothermal performance and vast potential for practical applications. The film is also used as an electromagnetic shielding film and heat dissipation substrate, showing exceptional electromagnetic shielding (42.5 dB) and heat dissipation properties.

Molecular Dynamics Analysis of Surface-Modified Carbon Nanoparticle Reinforced Epoxy Resin.

Surface-modified carbon nanoparticles (CNPs) as reinforcement materials have attracted significant attention due to their potential for substantially enhancing mechanical properties. However, the development and application of CNP-enhanced polymeric materials are constrained by an incomplete understanding of their reinforcement mechanisms, impeding sustainable progress. In this study, we employed molecular dynamics simulations to investigate the mechanical properties of surface-modified CNP-reinforced epoxy resin composites at the microscopic scale. The simulations focused on the tensile process and the nanopinning effect of CNPs within the epoxy resin matrix. Our results indicate that surface-modified CNPs form stronger interfacial connections with the epoxy resin, leading to enhanced mechanical strength of the composites. Quantitative analysis revealed that these composites exhibit higher tensile strength compared to nonmodified counterparts, with a significant improvement in stability due to the robust noncovalent interactions between CNPs and the epoxy matrix. This study elucidates the reinforcement mechanisms of surface-modified CNPs in polymers, providing valuable insights for further optimization and sustainable development of CNP-reinforced polymeric materials.

Fabrication of highly conductive VXC-72R carbon nanoparticles decorated Zr (IV)-based metal-organic framework for highly sensitive detection of methyl parathion

A simple and efficient ultrasonic-assisted strategy was used to prepare the nanocomposite of Vulcan XC-72R carbon (VXC-72R) nanoparticles and Zr(IV)-based metal-organic framework (UIO-66) nanoparticles. For the multifunctional VXC-72R@UIO-66 nanocomposite, VXC-72R nanoparticles possessed good conductivity property and good dispersion, which were conductive to form the interconnected carbon conductive channels; UIO-66 nanoparticles could improve the accumulation ability of methyl parathion (MP) because of the high affinity of Zr-O groups with phosphoric groups. Moreover, the introduction of VXC-72R nanoparticles could effectively make up the conductivity property of UIO-66 nanoparticles. The VXC-72R@UIO-66/GCE sensor presented good MP detection performance with limit of detection (LOD) of 1.35 nM (Linear MP concentration range: 0.01–10 μM). When used for the detection of MP in juice samples, the VXC-72R@UIO-66/GCE sensor showed acceptable recoveries of 96.00–104.67 %.

Development and characterization of flexible carbon temperature sensors: a study on different inks and sensor designs

Several industries and applications rely on the accurate monitoring of temperature. Consequently, the development and integration of reliable and flexible temperature sensors that are able to conform to different surfaces is desirable. Despite being a known fact that the used materials, chosen technologies, sensor size, and design tend to impact the performance of said sensors, not many studies focus on the analysis of the influence of these factors. As a result, this work intended to explore how the performance of carbon-based screen-printed temperature sensors could be tuned or optimized by changing the ink and the design of the printed sensors. Therefore, two commercial carbon inks and three different designs were used to create the herein-studied temperature sensors. Firstly, to explore potential differences between the used inks, their morphologic, chemical, and electrical properties were evaluated, allowing further insights to be gathered regarding the filler type, composition, and bulk resistivity. After printing the sensors, they were also submitted to electrical impedance spectroscopy, which allowed for a circuit equivalent model to be proposed for each sensor type, unraveling how current flew across the printed materials. Then, a full factorial statistical analysis was outlined and conducted to uncover which combination of factors allowed to optimize the sensors’ performance, i.e. lower initial resistance, higher thermal coefficient of resistance (TCR), and higher correlation coefficient (R2) of the responses. To gather the experimental data, the electrical response of the sensors (resistance variation) to increasing temperature was collected. As a result of these experiments, it was revealed that ink 1 (based upon carbon nanoparticles) allowed to obtain less resistive sensors and, even though ink 2 (based upon carbon nanotubes) presented higher sensitivity, ink 1 resulted in higher linearity of the sensors. Overall, the factor design had less influence on the results than the factor ink. Notwithstanding, design 1 could be used to obtain sensors with lower native resistance and higher linearity. To sum up, using ink 1 combined with design 1 (fewer hoops and thicker line width) allowed to obtain temperature sensors with average resistance at room temperature of 7.8 kΩ, a TCR of 1.13 %.ºC−1, and R2 of 0.99, which means the herein studied sensors present a very promising behavior when compared to the sensors in the preexisting literature. Thus, the proposed optimized sensors presented attractive characteristics as flexible printed temperature sensors.

Additive application for modulating physicochemical properties and antitumor effects of CaCO3 nanodelivery systems

Calcium carbonate (CaCO3) nanoparticles are highly regarded for their excellent biocompatibility and distinctive pH responsiveness, making them an ideal nanocarrier system for anti-tumor therapy. The incorporation of additives during the preparation of CaCO3 can significantly influence its morphology, particle size, and tumor inhibitory effects, necessitating a systematic study of these impacts. This study utilized the gas diffusion method to prepare CaCO3 nanoparticles, introducing various additives such as hyaluronic acid, polyacrylic acid, polyvinyl pyrrolidone, fucoidan, and polyethyleneimine. Different additives were found to have diverse effects on the morphology, particle size, zeta potential, and pH responsiveness of CaCO3. Methotrexate was employed as a model drug to evaluate the cytotoxicity of CaCO3 nanoparticles with different additives. Among them, hyaluronic acid-modified CaCO3 nanoparticles exhibited ideal morphology, particle size, significant pH responsiveness, and tumor-targeting capabilities. In vitro and in vivo experiments demonstrated their remarkable antitumor effects.

NIR-II Responsive Fe-Doped Carbon Nanoparticles for Photothermal-Enhanced Chemodynamic Synergistic Oncotherapy.

Phototherapy has demonstrated substantial development because in the second near-infrared (NIR-II) window it has a larger tissue penetration and fewer adverse consequences. In this work, a particular kind of NIR-II responsive Fe-doped carbon nanoparticles (FDCNs) is synthesized using a one-pot hydrothermal method for combined photothermal and chemodynamic therapy. The mesoporous nanostructure of FDCN, which has a size distribution that exceeds 225 nm, allows for effective acidification. The iron ions released from these nanoparticles can catalyze the decomposition of hydrogen peroxide (H2O2) into hydroxyl radical (•OH) for chemodynamic therapy (CDT). In addition to their CDT utility, FDCN can effectively adsorb and transform 1064 nm light into local heat, achieving a photothermal conversion efficacy (PCE) of 36.3%. This dual functionality not only allows for the direct eradication of cancer cells through photothermal therapy (PTT) but also enhances the chemodynamic reaction, creating a synergistic effect that amplifies the therapeutic outcome. The FDCN has demonstrated remarkable anticancer activity in both cellular and animal tests without incurring major systemic toxicity. This suggests that the compound has great promise for use in clinical cancer therapy.

Electrofluids with Tailored Rheoelectrical Properties: Liquid Composites with Tunable Network Structures as Stretchable Conductors.

Flexible and stretchable electronics require both sensing elements and stretching-insensitive electrical connections. Conductive polymer composites and liquid metals are highly deformable but change their conductivity upon elongation and/or contain rare metals. Solid conductive composites are limited in mechanoelectrical properties and are often combined with macroscopic Kirigami structures, but their use is limited by geometrical restraints. Here, we introduce "Electrofluids", concentrated conductive particle suspensions with transient particle contacts that flow under shear that bridge the gap between classic solid composites and liquid metals. We show how Carbon Black (CB) forms large agglomerates when using incompatible solvents that reduce the electrical percolation threshold by 1 order of magnitude compared to more compatible solvents, where CB is well-dispersed. We analyze the correlation between stiffness and electrical conductivity to create a figure of merit of first electrofluids. Sealed elastomeric tubes containing different types of electrofluids were characterized under uniaxial tensile strain, and their electrical resistance was monitored. We found a dependency of the piezoresistivity with the solvent compatibility. Electrofluids enable the rational design of sustainable soft electronics components by simple solvent choice and can be used both as sensor and electrode materials, as we demonstrate.

Phase change polymer-based structural color photonic films for contactless and inkless writing irreversibly

Thermal-responsive photonic crystals (PCs) have attracted considerable interest due to their triggerable and adjustable optical capabilities, which are promising for various applications. However, developing a mechanism for rapid and irreversible structural color transformation in PCs that enables contactless and inkless writing has significant research value. Herein, phase change polymers are incorporated into functional optical platforms capable of rapid and irreversible structural color transformation in response to thermal stimuli. In crystalline state, phase change polymers used as inverse opal scaffolds in photonic films produce structural color with high saturation. The collapse of the highly ordered inverse opal structure, driven by thermal-mediated transformation during the crystalline/amorphous conversion of phase change polymers, is identified as the primary mechanism for achieving rapid and irreversible structural color transformation. These significant color variations between the inverse opal and collapsed structures provide high color contrast and resolution. The photonic films exhibit excellent hydrophobicity, solvent resistance, and storage stability. Additionally, incorporating the photothermal material carbon black (CB) enhances color saturation and imparts efficient photothermal conversion ability to films. By modulating the photothermal effect via near-infrared (NIR) laser light, phase change polymer-based structural color photonic films can achieve a permanent configuration at 42 °C, resulting in high-resolution images. These outstanding features offer a feasible method for next-generation innovative inkless writing and printing.

Integrating Mo2C/C as cocatalyst into S-scheme Mo2C/C/Co0.5Cd0.5S heterojunction with spatial photocarrier separation for photocatalytic synergistic H2 evolution

Reasonable design and production of potent photocatalysts for sustainable H2 production from solar energy is one of the necessary strategies in the photocatalysis process. The S-scheme heterojunction exposes remarkable superiority in boosting light harvesting and progressing photocarrier separation efficiency in the photocatalyst. Here, new S-scheme heterojunction Mo2C/C/Co0.5Cd0.5S photocatalysts, including different weights of noble metal-free Mo2C/C nanostructures as cocatalysts, were successfully synthesized. As expected, the nanocomposite structures exhibited increased photocatalytic activity relative to single Co0.5Cd0.5S. The nanocomposite containing 5 wt% Mo2C/C exhibited an increased hydrogen production efficiency of 83.86 mmol g−1 h−1, which was 8.4 times higher than single Co0.5Cd0.5S (10.06 mmol g−1 h−1). This implies that for Co0.5Cd0.5S, Mo2C/C increases visible light absorption, facilitates photocarrier separation, and boosts the H2 evolution rate. Moreover, conductive carbon nanoparticles, electron mediators with strong interfacial interaction, serve as rapid photocarrier transfer bridges between Co0.5Cd0.5S and Mo2C. In summary, the superb efficiency of Mo2C/C/Co0.5Cd0.5S is accredited to the synergistic effect between Co0.5Cd0.5S and Mo2C/C, the creation of S-scheme heterojunction, which assists the separation of photocarriers and declines the recombination possibilities. This research ensures a reference and new profound insight for understanding and designing noble metal-free cocatalyst-assisted S-scheme heterojunctions for immensely efficient photocatalytic H2 production.

Carbon black dispersing agents based on fully hydrophilic poly(N‐vinylamide): Surface adsorption via selective interactions

AbstractInterface‐stabilizing polymers are frequently used in commercial applications to provide long‐lasting dispersions of colloids in liquid media. Dispersing high concentrations of pigments in aqueous solution can be particularly challenging. Here, we present a novel, fully hydrophilic dispersing agent system for carbon black (CB) pigments based on partially hydrolyzed poly(N‐vinylamides). These highly water‐soluble polymers adsorb onto CB through specific interactions between the polymer and surface‐bound moieties, rather than the hydrophobic effect. They participate in hydrogen bonding, ion–dipole interactions and can be partially positively charged to engage in ion pair formation, providing strong surface affinity. Dispersants are synthesized using free radical copolymerization of N‐vinylform‐ and ‐acetamide, acidic hydrolysis, and subsequent PEGylation. Molecular water solubility of the synthesized polymers is confirmed by using fluorescence spectroscopy. Highly concentrated CB dispersions are prepared in acidic, neutral, and basic media, which we identify to strongly affect the interactions between polymer and CB. The stability of CB dispersions is analyzed using ultracentrifugation and thermogravimetric analysis. The presented polymers are able to provide significantly more stable dispersions than a commercial reference product, showcasing the suitability of poly(N‐vinylamines) as potent CB dispersing agents.

Simultaneous electrical and mechanical properties improvement for composite expanded graphite bipolar plate by incorporating surface-activated carbon black paving on the carbonized melamine foam skeleton

The bipolar plate is the critical component that directly impacts the output performance and lifespan of the fuel cell. Composite graphite-based bipolar plates, which can be tailored to exhibit desired properties, are promising candidates for high-performance fuel cells. However, the simultaneous optimization of their electrical and mechanical properties has been a major challenge in the field. This study introduces a foam skeleton made of carbonized melamine foam (CMF) into the graphite bipolar plate to create ample space for subsequent resin impregnation. Carbon black (CB) is added as a filler to form complete conductive paths, which is modified using low-temperature plasma to allow it to be more uniformly adsorbed in the skeleton. The microstructure design of the composite bipolar plate ensures excellent mechanical properties and significantly enhances its electrical conductivity. Moreover, it effectively eliminates the impact of carbon black on the surface roughness of the composite plate. This design also provides superior water management and reduces gas permeability. Practical application tests demonstrate that the developed composite plate exhibits better corrosion resistance and electrochemical stability than metal bipolar plates. Compared to carbonized bipolar plates, it displays better impact resistance and stability.

Characterization of an additively manufactured coating using an upsetting test with miniaturized cylindrical specimen

In order to reduce CO2 emissions in production industry, the combination of several manufacturing processes is coming to the fore. One example is the combination of metal additive manufacturing with the forming technology, whereby the advantages of both process technologies can be used. The process combination can be applied to produce hybrid barrel sleeves, for example. Using a laser-based directed energy deposition (DED-LB/M), a circular coating is first applied to a blank, which is then deep-drawn in a second step. The additive layer serves as a wear-resistant coating. One way to increase process understanding for this process combination is numerical simulation. An important part of setting up the simulation model is characterizing the material in terms of its mechanical behavior. In order to avoid long building times, small sample geometries are suitable for characterizing the additive material. In the context of the paper, the upsetting test is therefore carried out with miniaturized specimens, whereby not only the base material Bainidur AM but also the addition of tungsten carbide microparticles and carbon nanoparticles is investigated. The in-situ modification of the material significantly increases the yield strength, but at the same time reduces the ductility. The microhardness of the material is also increased by the addition of carbon or tungsten carbide.

Fatigue investigations of elastomers developed for high-pressure hydrogen gas environments

Hydrogen possesses many characteristics to be an ideal candidate as a more sustainable energy carrier, especially for the transport sector. For a proper optimization of this abundant resource, hydrogen needs to be compressed, and stored in high-pressure conditions, which demands improvement in technology and the development of appropriate materials. In this context, elastomeric sealing components play a critical role and they need to withstand harsh working conditions, for example, high-pressure, wide temperature range, cyclic exposure conditions, etc. In this work, eight different grades designed for this application were analyzed in terms of fatigue behavior and long-term performance. This was verified through fatigue crack growth experiments, the energy dissipation, and temperature increase during crack propagation were analyzed and correlated with micro-structural differences of materials. Furthermore, the materials were investigated at large and small deformations through uniaxial tensile tests and Dynamic Mechanical Analysis (DMA), respectively. It was found that only with the addition of a coupling agent can silica-filled NBR have properties similar to carbon black (CB) filled NBR, despite a reduction in both fatigue strength and energy dissipation. Coupling agents also involved an increase in bound rubber. Regarding CB-filled compounds, with peroxide crosslinking a reduction in fatigue strength was found, while no effect on the quantity of bound rubber was observed. Increased CB content in NBR grades led to decreased fatigue resistance and higher energy dissipation; higher bound rubber content was found as well. Also for EPDM grades, increased CB content resulted in reduced fatigue resistance. Despite an increase in energy dissipation, the content of bounded rubber was the same even with higher CB content.

Highly Graphitized Coal Tar Pitch-Derived Porous Carbon as High-Performance Lithium Storage Materials.

Because of its high specific capacity and superior rate performance, porous carbon is regarded as a potential anode material for lithium-ion batteries (LIBs). However, porous carbon materials with wide pore diameter distributions suffer from low structural stability and low electrical conductivity during the application process. During this study, the calcium carbonate nanoparticle template method is used to prepare coal tar pitch-derived porous carbon (CTP-X). The coal tar pitch-derived porous carbon has a well-developed macroporous-mesoporous-microporous hierarchical porous network structure, which provides abundant active sites for Li+ storage, significantly reduces polarization and charge transfer resistance, shortens the diffusion path and promotes the rapid transport of Li+. More specifically, the CTP-2 anode shows high charge capacity (496.9 mAh g-1 at 50 mA g-1), excellent rate performance (413.6 mAh g-1 even at 500 mA g-1), and high cycling stability (capacity retention rate of about 100 % after 1,000 cycles at 2 A g-1). The clean and eco-friendly large-scale utilization of coal tar pitch will facilitate the development of high-performance anodes in the field of LIBs.

Incorrectly Focused Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG) Laser Beam Leads to Massive Destructive Effects in Small-Aperture (Pinhole) Intraocular Lenses.

Pinhole intraocular lenses (IOLs) were developed to improve reading by compensating for loss of accommodative function. The IC-8® Apthera™ is a small-aperture presbyopia-correcting IOL that combines the proven principle of small-aperture optics with an aspheric monofocal lens to deliver a continuous range of vision for patients withcataractsfrom distance to near vision. Posterior capsule opacification is the most common sequela after cataract surgery. It is effectively treated by laser capsulotomy. However, if the laser beam is incorrectly focused, the IOL can be permanently damaged (pits/shots). In this experimental study, yttrium-aluminum-garnet (YAG) pits were purposefully created. Defects were analyzed and compared between the periphery of the ring in the clear area of the hydrophobic acrylic lens and at the carbon black (CB)-polyvinylidene fluoride (PVDF) filtering component (FilterRing™) of the pinhole lens. All defects were made using identical settings/energy levels (2.6mJ). The damage induced to the IC-8® Apthera™ IOL was examined by low-magnification images, light microscopy, scanning electron microscopy, and micro-computed tomography (micro-CT). YAG defects in the carbon black filter ring were much more severe than those in the clear zone due to the high absorption of the carbon black. Massive defects and destruction of the lens with tearing out of fragments and particles were observed. The missing volume calculated from the micro-CT reconstruction was 0.266 mm3, which is 1.6% of the entire IOL volume, or more than 1000 times the volume damaged in the largest shot in the periphery. Based on the results, we highly recommend using the lowest possible energy levels, posterior offset setting, and circular pattern for maximum safety when performing laser capsulotomy with pinhole implants. Care should be taken to avoid creating irreversible iatrogenic defects that may affect overall quality. The safest area for performing capsulotomy seems to be the periphery of the ring segment. Video available for this article.

Electrochemical detection of anti-tissue transglutaminase antibody using quantum dots-doped polypyrrole-modified electrode

A nanohybrid-modified glassy carbon electrode based on conducting polypyrrole doped with carbon quantum dots (QDs) was developed and used for the electrochemical detection of anti-tissue transglutaminase (anti-tTG) antibodies. To improve the polypyrrole conductivity, carrier mobility, and carrier concentration, four types of carbon nanoparticles were tested. Furthermore, a polypyrrole-modified electrode doped with QDs was functionalized with a PAMAM dendrimer and transglutaminase 2 protein by cross-linking with N-hydroxysuccinimide (NHS)/N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDC). The steps of electrode surface modification were surveyed via electrochemical measurements (differential pulse voltammetry (DPV), impedance spectroscopy, and X-ray photoelectron spectroscopy (XPS)). The surface characteristics were observed by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and contact angle measurements. The obtained modified electrode exhibited good stability and repeatability. DPV between − 0.1 and 0.6 V (vs. Ag/AgCl 3 M KCl reference electrode) was used to evaluate the electrochemical alterations that occur after the antibody interacts with the antigen (transglutaminase 2 protein), for which the limit of detection was 0.79 U/mL. Without the use of a secondary label, (anti-tTG) antibodies may be detected at low concentrations because of these modified electrode features.Graphical

Signalling Pathways of Inflammation and Cancer in Human Mononuclear Cells: Effect of Nanoparticle Air Pollutants.

Fine inhalable particulate matter (PM) triggers an inflammatory response in the airways and activates mononuclear cells, mediators of tissue homeostasis, and tumour-promoting inflammation. We have assessed ex vivo responses of human monocytes and monocyte-derived macrophages to standardised air pollutants: carbon black, urban dust, and nanoparticulate carbon black, focusing on their pro-inflammatory and DNA-damaging properties. None of the PM (100 μg/mL/24 h) was significantly toxic to the cells, aside from inducing oxidative stress, fractional DNA damage, and inhibiting phagocytosis. TNFα was only slightly increased. PM nanoparticles increase the expression and activate DNA-damage-related histone H2A.X as well as pro-inflammatory NF-κB. We have shown that the urban dust stimulates the pathway of DNA damage/repair via the selective post-translational phosphorylation of H2A.X while nanoparticulate carbon black increases inflammation via activation of NF-κB. Moreover, the inflammatory response to lipopolysaccharide was significantly stronger in macrophages pre-exposed to urban dust or nanoparticulate carbon black. Our data show that airborne nanoparticles induce PM-specific, epigenetic alterations in the subsets of cultured mononuclear cells, which may be quantified using binary fluorescence scatterplots. Such changes intercede with inflammatory signalling and highlight important molecular and cell-specific epigenetic mechanisms of tumour-promoting inflammation.

Catalytic Activity of Incorporated Palladium Nanoparticles on Recycled Carbon Black from Scrap Tires.

A stable support substrate for catalytically active metal nanoparticles (NPs) plays an important role in various chemical transformation reactions. This study describes the effective integration of catalytically active palladium nanoparticles (PdNPs) into recycled carbon black (rCB) obtained from scrap tires. The loading efficiency and dispersion degree of PdNPs prepared via a deposition-precipitation method are thoroughly compared to those prepared with conventional Vulcan CB. As the rCB powder exhibits relatively larger surface areas and wider pore size distributions, slightly polydisperse and more PdNPs are integrated across rCB than those on CB. These composite materials are subsequently tested as catalysts in the Suzuki coupling and styrene hydrogenation reactions. For the Suzuki reaction using phenylboronic acid and bromobenzene, the PdNPs on rCB exhibit slightly higher reactivity than those on CB (TOF of ∼9/h vs ∼8/h), presumably due to the structural features of the integrated PdNPs and the relatively hydrophobic characteristics of the rCB substrate. For the hydrogenation reaction, both composite materials easily result in over 99% yield under ambient conditions with similar activation energies of ∼32 kcal/mol. These composite materials are also recyclable in both reactions without a detectable loss of the PdNP catalyst and its activity. Understanding the physicochemical properties of rCB and demonstrating their potential use as a catalyst support substrate evidently suggest the possibility of replacing conventional CB, which also provides an idea of upcycling waste tires in the development of practical and green reaction systems.

Nitrogen-Doped Carbon Dots: A New Powerful Fluorescent Dye with Substantial Effect on Bacterial Cell Labeling.

Carbon dots (CDs)-minute carbon nanoparticles with remarkable luminescent properties, photostability, and low toxicity-show potential for various applications. CDs synthesized using citric acid and urea are the least toxic to biological environments. Here, we aimed to explore the effect of CDs synthesized using citric acid and urea at 50, 33, and 25% (CDs 1/1, 1/2, and 1/3, respectively) weight ratios in a microwave on bacterial cell fluorescence sensing and labeling. The nanoscale properties of CDs were investigated via transmission electron microscopy and dynamic light scattering particle size analysis. X-ray powder diffraction confirmed the graphitic structures of CDs. X-ray photoelectron spectroscopy revealed that the nitrogen content increased gradually with increasing urea ratios, indicating functional group changes. Transient photoluminescence decay periods demonstrated superior fluorescence intensity of CDs 1/3 under blue, green, and red lights. The use of CDs was notably more efficient than traditional methods in staining bacterial cells. Fluorescence microscopy of 10 g-positive and 10 g-negative bacteria revealed enhanced staining of Gram-positive strains, with CDs 1/3 presenting the best results. The CDs exhibited excellent photostability, maintaining poststaining fluorescence for 100 min, surpassing the performance of conventional dyes. CDs could serve as potential fluorescent dyes for the rapid discrimination of Gram-positive and Gram-negative bacteria.