Nanocomposite Surface Research Articles

Facile synthesis and characterisations of cobalt ferrite-silver-graphene oxide nanocomposite in enhancing electrochemical response capacity

In this report, cobalt ferrite nanoparticles (CoFe2O4 NPs) synthesised from the co-precipitation method were strongly connected with graphene oxide nanosheets (GO) via ‘bridge molecules’- polyhexamethylene biguanide hydrochloride (PHMB)’. Silver (Ag) NPs were grown on the surface of CoFe2O4-GO nanocomposites to improve the electrical conductivity and electrocatalytic ability of the proposed functional nanocomposites. Characteristics of the synthesised materials were investigated via x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, cyclic voltammetry (CV), and differential pulse voltammetry (DPV). The obtained results demonstrate that the CoFe2O4-Ag-GO nanocomposites could significantly improve the adsorption ability and electron transfer between electrode and analytes owing to the synergetic effect of Ag NPs, CoFe2O4 NPs, and GO. The prepared CoFe2O4-Ag-GO nanocomposites showed the highest electrochemical response for chloramphenicol antibiotic detection, with current intensity response (∼24.4 μA) being 3.25 and 2.57 times higher than that of CoFe2O4 NPs (7.5 μA) and CoFe2O4-GO (9.5 μA), respectively. The calibration plot is linear in the 1–50 μM CAP concentration range, with a detection limit of 0.1 μM. With excellent electrochemical properties, the CoFe2O4-Ag-GO nanocomposites are expected to be a potential candidate for advanced electrochemical sensing applications.

Ag-Se/Nylon Nanocomposites Grown by Template-Engaged Reaction: Microstructures, Composition, and Optical Properties.

Ag–Se nanostructure films were deposited on a–Se/nylon templates by a template-engaged reaction. Firstly, amorphous selenium (a–Se) was deposited on nylon by employing the chemical bath deposition method while using H2SeO3 and Na2SO3 solutions with an increasing selenium deposition time. Then, these a–Se/nylon templates were exposed into AgNO3 solution at ambient temperature and pressure. The Ag–Se/nylon nanocomposites surface morphology, elemental and phase composition, and optical properties were monitored depending on the selenium deposition time on nylon. Scanning electron microscopy (SEM) analysis confirmed the development of a very complex surface composed of pyramidal-like sub-micron structures, agglomerates, and grid-like structures. Energy dispersive spectroscopy (EDS) proved the presence of carbon, oxygen, nitrogen, selenium, and silver. SEM/EDS cross-sectional analysis confirmed the multilayer character with different individual elemental composition in each film layer. X-ray diffraction analysis revealed a polycrystalline Ag2Se phase with or without metallic Ag. The RMS value obtained from atomic force microscopy varies from 25.82 nm to 57.04 nm. From the UV-Vis spectrophotometry, the direct optical band gaps were found to be 1.68–1.86 eV. Ag–Se/nylon composites exhibit high refractive indices in the near infrared region.

Physicochemical and biological properties of nanohydroxyapatite grafted with star-shaped poly(ε-caprolactone)

To overcome the disadvantages generated by the lack of interfacial bonding between hydroxyapatite nanocrystals (HAPN) and agglomeration of particles in the development of biodegradable nanocomposites a chemical grafting method was applied to modify the surface of HAPN through grafting of the three-arms star-shaped poly(ε-caprolactone) (SPCL) onto the nanoparticles. The chemical grafting of SPCL onto HAPN (SPCL-g-HAPN) has been investigated using Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy (TEM), photoelectron spectroscopy, X-ray diffraction, zeta potential (ZP) and contact angle (CA). TEM micrographs of the SPCL-g-HAPN revealed the existence of hybrid organic/inorganic (O/I) nanoscale domains. The results of albumin (HSA) and fibrinogen (HFb) adsorption indicate resistance to HFb adsorption by SPCL-g-HAPN relatively to unmodified HAPN. The ZP and CA measurement suggest a heterogeneous topology for SPCL-g-HAPN likely due to the existence of hydrophobic-hydrophilic regions on the nanocomposite surface. The enzyme degradation by cholesterol esterase and lipase indicates that the rates of hydrolysis for SPCL-g-HAPN were very slow relative to the SPCL/HAPN blends. The in vitro biological studies showed that the human osteoblast-like cells (MG-63) cells had normal morphology and they were able to attach and spread out on SPCL-g-HAPN surfaces. A higher overall cellular proliferation was observed on SPCL-g-HAPN scaffolds compared to pure HAPN or SPCL materials.

X‐Ray Shielding Performance and Characterization of Electrospun PVC/Bismuth(III) Oxide Nanocomposites

AbstractTo develop an alternative surface to lead‐based shieldings, we synthesized bismuth(III) oxide‐free and bismuth(III) oxide‐loaded poly(vinyl) chloride solutions via electrospinning process. Nanocomposite surfaces were characterized by scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis and fourier transform infrared spectroscopy. Thickness and electrical conductivity of different samples were measured and linear attenuation coefficients, half‐value length, tenth‐value length, mean‐free path and shielding performance were calculated with corresponding formula. The attenuation behaviors of samples were plotted by X‐COM software. According to results of instrumental analysis, micro‐particulated bismuth(III) oxide powder was adapted into nanofibrous structures and bismuth(III) oxide loading lead to development on thermal behaviors. Besides, bismuth(III) oxide‐loaded poly(vinyl) chloride samples showed limited electrical conductivity and improved X‐ray radiation attenuation. Increasing weight percentage of bismuth(III) oxide caused a decrease on half‐value length, tenth‐value length and mean‐free path values. It was concluded that studied samples should be used as multi‐layer form for achieving desired radiation dose reduction. By increasing w% of bismuth(III) oxide powder, more effective surfaces for radiation shielding can be manufactured.

An innovative dual recognition aptasensor for specific detection of Staphylococcus aureus based on Au/Fe3O4 binary hybrid

Pathogenic bacteria cause disease outbreaks and threaten human health, prompting the research on advanced detection assays. Herein, we developed a selective molecular imprinted aptasensor for sensitive and prompt quantitation of Staphylococcus aureus (S. aureus) bacteria. The aptasensor was constructed by immobilization of aptamer on gold nanoparticles modified magnetic nanoparticles (apt-AuNPs@ Fe3O4). A functional monomer (o-phenylenediamine, o-phen) was electro-polymerized on the surface of the as-synthesized nanocomposite in the presence of a template (S. aureus). After removing S. aureus, the formed imprinted sites were available to extract pathogenic bacteria from complicated matrices. The surface morphology of the as-fabricated nanocomposites was characterized using different spectroscopic and electrochemical methods. Moreover, we thoroughly evaluated factors affecting the synthesis and determination procedures. The molecular imprinted aptasensor exhibited a wide linear range of 101–107 CFU mL−1 with a Limit of Detection, LOD (signal to noise = 3) of 1 CFU mL−1. The aptasensor detected S. aureus in milk, conduit water, and apple juice samples with good recoveries % and satisfactory relative standard deviations (RSDs %) values.

A Novel Automatic Image Intensity Analysis Using Machine Learning Algorithms and Characterization of Tensile Fracture Surface of AA8011-B4C Nano-composite

A Novel Automatic Image Intensity Analysis Using Machine Learning Algorithms and Characterization of Tensile Fracture Surface of AA8011-B4C Nano-composite

Sensing gastric cancer exosomes with MoS2-based SERS aptasensor

Exosomes have been widely used in early cancer diagnosis as promising cancer biomarkers due to their abundant tumor-specific molecular information. In this study, we developed a sensitive and straightforward surface-enhanced Raman scattering (SERS) aptasensor to detect exosomes based on gold nanostars-decorated molybdenum disulfide (MoS2) nanocomposites (MoS2-AuNSs). ROX-labeled aptamers (ROX-Apt) were assembled on MoS2-AuNSs surface as recognition probes that specifically bind with transmembrane protein CD63 (a representative surface marker on exosomes). Thus obvious ROX Raman signals were obtained through the synergistic Raman enhancement effect of AuNSs and MoS2 nanosheet. In presence of exosomes, ROX-Apt is preferentially tethered onto exosomes and released from the surface of nanocomposites, resulting in a decrease of the SERS signal. Expectedly, the as-fabricated SERS aptasensor was capable of detecting exosomes in a wide range from 55 to 5.5 × 105 particles μL−1 with a detection limit of 17 particles μL−1. Moreover, the aptasensor exhibited accepted stability and potential clinical applicability.

Analysis of Fouling on Nanocomposite Surfaces in Plate Heat Exchangers

Abstract In the application of plate heat exchangers (PHEs), fouling has always been an intractable problem that results in decreasing the heat transfer efficiency and increasing the associated pressure drop. Plate heat exchangers are employed in solar energy systems to transfer the solar heat to a working fluid that can be used for heating or power generation applications depending on the amount of heat collected per unit surface area. The work upon which this article partially reports presents analyses of the factors influencing the antifouling performance of two types of nanocomposite surfaces, namely, Ni-P-PTFE and Ni-P-TiO2. In this work, the flow and thermal fields in PHEs are numerically analyzed. Then, experiments are conducted to verify the numerical results. The influencing factors of fouling are theoretically analyzed employing the Kern–Seaton fouling model and the von Kármán analogy. Results of the work performed here show that the friction factor f, the mass transfer coefficient Km, and the shear stress τs of the Ni-P-TiO2 and Ni-P-PTFE nanocomposite surfaces all decrease compared with an uncoated surface. Results also indicate that the deposit bond strength ζ of the Ni-P-TiO2 and Ni-P-PTFE coatings decrease by 42.1% and 30.5%, respectively. Furthermore, the Ni-P-TiO2 coating was found to increase the probability P of sticking to the surface by 24.9%, while the Ni-P-PTFE coating decreased the sticking probability P by 2.7%.

Depollution of Synthetic dyes From Waste Water Using Polyazomethine/TiO2 And Polyazomethine/ZnO Nanocomposites Via Photocatalytic Process

<p>We propose a simple method for synthesising Poly(azomethine), ZnO, TiO2, poly(azomethine)/TiO2, and poly(azomethine)/ZnO nanocomposites using an ultrasonication process, as well as the use of these nanomaterials for photocatalytic degradation of organic dyes (Methylene blue (MB), malachite green (MG), Bismarck brown (BB), alizarin red S (ARS), and (MO). Our findings show that precise control and optimization of ambient factors in the presence of natural sunlight can result in efficient tailoring of poly(azomethine)/TiO2 (PNT) and poly(azomethine)/ZnO (PNZ) nanocomposites. Compared to Poly(azomethine), ZnO, TiO catalysts, the PNT and PNZ composites exhibit better photocatalytic activity for MB, MG, BB, ARS, MO degradation, which could be attributed to the formation of special catalytically active structures on the nanocomposite surface. The synthesized PNT and PNZ composites had the maximum catalytic activity under circumstances of 500 mg photocatalyst dose, 5 h of sunlight exposure and 10 ppm dye concentrations. Under ideal conditions, MB degrades at a rate of 97 % after 5 h of sunlight exposure. The composites demonstrated selective dye degradation and have greater photocatalytic effectiveness for cationic dyes. This research could lead to the simple development of a high photocatalysts for the rapid removal of ecologically harmful dyes from aqueous solutions.</p>

Synthesis and Characterizations of Novel Spinel Ferrites Nanocomposites Al0.5Cr0.5Zn0Fe2O4 and Zn0.5Cr0.5Al0Fe2O4

In this study, novel spinel ferrites nanocomposites containing aluminum chromium zinc nanoferrites, Al0.5Cr0.5Zn0Fe2O4 and Zn0.5Cr0.5Al0Fe2O4 have been fabricated and characterized to determine the properties of highly stable conduction materials. The nanocomposites have been synthesized through the sol–gel method. Zinc and aluminum-doped chromium ferrites were prepared with the stoichiometric composition ZnxAlx-0.5Cr0.5Fe2O4 with ammonium hydroxide solution (NH4OH) and polyethylene glycol (PEG) at different temperatures with consecutive steps. After sintering the final nanoferrites, characterizations for morphological, spectral properties, and crystallinity have been determined through scanning electron microscope (SEM), Fourier transformation infrared spectroscopy, and X-ray diffraction spectrometer, respectively. SEM micrographs presented that higher sample density and agglomeration of the nanocomposite outer surface with temperature increase. The investigation of the dielectric and conduction properties presented with varying sintering temperature and Al–Zn doping greatly influenced the dielectric properties of spinel nanoferrites dielectric properties: dielectric loss tangent and dielectric constant. The effects of various sintering temperatures provide synergistic effects on the morphology and dielectric conductivity features. The characterizations presented that the dopants (Al, Zn) enhanced the magnetic and electrical properties of both chromium nanoferrites which can be implemented in high frequency single-layered electromagnetic waves absorbing devices in electrical and medical appliances in future.

Gas cluster etching for the universal preparation of polymer composites for nano chemical and mechanical analysis with AFM

Atomic force microscopy (AFM) based techniques that probe nanomechanical and nanochemical features are valuable tools for studying composite surfaces at high-resolution. However, the application of AFM, particularly at resolutions less than 50 nm per pixel, is limited to sample surfaces that are smooth relative to the tip dimensions and damage-free. As a result, high-resolution AFM is limited in technologically relevant polymer composite systems where current sample preparation techniques can fail to produce the necessary pristine surfaces. Here, we apply gas cluster ion beam (GCIB) etching to prepare composite materials for nanomechanical and nanochemical analysis. We demonstrate that the GCIB can effectively remove material and produce damage free surfaces for composites comprised of PMMA or PS confined in the 7 nm diameter pores of an organosilicate matrix. AFM-IR measurements on the etched region indicate a high degree of hydrogen bonding between the carbonyl groups of the confined PMMA and the hydroxyl groups on the pore walls, while maps of loss tangent can identify the 7 nm polymer domains within the organosilicate matrix. This work demonstrates that GCIB is an effective tool for nanocomposite surface preparation and could enable a new range of materials to be studied with AFM at high resolution.

Synthesizing and characterizing the magnetic EDTA/chitosan/CeZnO nanocomposite for simultaneous treating of chromium and phenol in an aqueous solution

A new magnetic nanocomposite chitosan/EDTA/CeZnO (MEC-CeZnO) is synthesized as an efficient and eco-friendly bio-compound for the removal of chromium Cr(VI) metal ions and phenol organic matters from aqueous solutions. Nanocomposites are characterized using field emission scanning electron microscope, energy dispersive X-ray spectroscopy, transmission electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, diffuse reflection spectroscopy, and PL methods. The reduction rate of Cr(VI) ions and phenol degradation is evaluated under various experimental conditions, separately and simultaneously. The average pore diameter and specific surface of MEC-CeZnO nanocomposite are obtained 50 nm and 210 m2·g−1 respectively, which suggest the successful synthesis of the nanocomposite because of the increased surface area and reduced pores in comparison to previous studies. Moreover, the best Cr(VI) and phenol reduction efficiencies are 98% and 92% at 180 min of retention time, both following the Langmuir–Hinshelwood first-order kinetics. The mechanisms of Cr(VI) and phenol removal from aqueous solutions involved Cr(VI) reduction, phenol oxidation, and adsorption. Examining the reusability of MEC-CeZnO showed that both degradation and recovery capacity is stable in 5 cycles.

Facile electrooxidation of ethanol on reduced graphene oxide supported Pt–Pd bimetallic nanocomposite surfaces in acidic media

Development of electrocatalysts with extended homogeneity and improved metal–support interactions is of urgent scientific need in the context of electrochemical energy applications. Herein, bimetallic Pt–Pd nanoparticles with good homogeneity are fabricated using a convenient solution phase chemical reduction method onto a reduced graphene oxide (rGO) support. X-ray diffraction studies revealed that Pt–Pd/rGO possesses the crystallite size of 3.1 nm. The efficacies of Pt–Pd/rGO catalyst (20 wt% Pt + 10 wt% Pd on rGO support, Pt:Pd atomic ratio = 1:1) towards ethanol electrooxidation reaction (EOR) are evaluated in acidic conditions by cyclic voltammetry using catalyst-coated glassy carbon electrode as a working electrode. With the better dispersion on rGO support the Pt–Pd/rGO nancomposite catalyst exhibit highest mass specific activity (0.358 mA/µg-Pt) which is observed to be 1.9 times of similarly synthesized 20 wt% Pt/rGO (0.189 mA/µg-Pt) and 2.5 times of commercial 20 wt% Pt/C (0.142 mA/µg-Pt), respectively. Apart from the observed improved EOR activity, the Pt–Pd/rGO catalyst exhibited better stability than Pt/rGO and Pt/C catalysts. Strong synergy offered by Pt, Pd and rGO support could contribute to the observed higher EOR activity of Pt–Pd/rGO.

Enhanced photoelectrochemical aptasensing for sensitive detection of diazinon pesticide used N-hydroxyphthalimide as an effective hole mediator

Signal amplification strategies are of great interest in photoelectrochemical (PEC) sensing research. Herein, we explored a novel approach whereby hole transfer was accelerated from the photosensitive material Blue-TiO2 (B-TiO2) to the hole mediator N-hydroxyphthalimide (NHPI). Simultaneously, the introduction of the organic molecule NHPI can promote the efficiency of visible light absorption and expand the absorption range of B-TiO2. Under visible light irradiation, the photocurrent value of NHPI/B-TiO2 is 2.7-fold larger than that of B-TiO2, which can be ascribed to the acceleration of hole transfer by NHPI. More specifically, NHPI acts as a hole mediator, which effectively transfers photo-generated holes from the valence band (VB) of B-TiO2 to NHPI. NHPI can be oxidized to phthalimide-N-oxyl radical (PINO*), thereby causing inhibition of photo-generated carrier recombination and enhancement of the photocurrent. Furthermore, a PEC aptasensor for the sensitive detection of diazinon (DIA) was constructed by combining specific aptamers on an NHPI/B-TiO2 nanocomposite surface. The oxidation product of NHPI, PINO*, oxidizes the DIA captured by the aptamer. Under optimized experimental conditions, the linear range for DIA detection was 0.1–1000 nM, and the detection limit of the NHPI/B-TiO2 nanocomposite aptamer sensing was 0.03 nM (S/N = 3). Therefore, this proposed method involving the hole mediator can be used as a new strategy to improve the performance of PEC.

Carboxymethyl Cellulose/Zn-Organic Framework Down-Regulates Proliferation and Up-Regulates Apoptosis and DNA Damage in Colon and Lung Cancer Cell Lines.

A solvothermal technique was used to prepare a Zn–benzenetricarboxylic acid (Zn@BTC) organic framework covered with a carboxymethyl cellulose (CMC/Zn@BTC). Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), and Brunauer, Emmett, and Teller (BET) surface area were applied to characterize CMC/Zn@BTC. Moreover, the anticancer, anti-migrative, anti-invasive, and anti-proliferative action of CMC/Zn@BTC nanoparticles were assessed on cancer cell lines. Apoptotic markers and DNA damage were assessed to explore the cellular and biological changes induced by CMC/Zn@BTC nanoparticles. The microscopic observation revealed that CMC controls the surface morphology and surface characteristics of the Zn@BTC. The obtained BET data revealed that the Zn@BTC nanocomposite surface area lowers from 1061 m2/g to 740 m2/g, and the pore volume decreases from 0.50 cm3/g to 0.37 cm3/g when CMC is applied to Zn@BTC nanocomposites. The cellular growth of DLD1 and A549 was suppressed by CMC/Zn@BTC, with IC50 values of 19.1 and 23.1 μg/mL, respectively. P53 expression was upregulated, and Bcl-2 expression was downregulated by CMC/Zn@BTC, which promoted the apoptotic process. Furthermore, CMC/Zn@BTC caused DNA damage in both cancer cell lines with diverse impact, 66 percent (A549) and 20 percent (DLD1) compared to cisplatin’s 52 percent reduction. CMC/Zn@BTC has anti-invasive properties and significantly reduced cellular migration. Moreover, CMC/Zn@BTC aims key proteins associated with metastasis, proliferation and programmed cellular death.

Synthesis and characterization of SiO2-NiO xerogel nanocomposite prepared by sol–gel method for catalytic reduction of p-nitrophenol

This manuscript describes the preparation and characterization of silica-nickel oxide (SiO2-NiO) xerogel nanocomposite and its catalytic application in the hydrogenation of p-nitrophenol. Hydrochloric acid and ammonium hydroxide were used as the acid and base catalyst, respectively during the synthesis of SiO2-NiO. The Fourier Transformation Infra-Red spectroscopic results supported the formation of the silica xerogel skeleton structure with corresponding characteristic peaks of siloxane linkage. The surface of SiO2-NiO xerogel nanocomposite was observed to be porous along with some irregular cracks. The X-Ray diffraction analysis showed that the SiO2-NiO xerogel nanocomposite was amorphous in nature. The synthesized xerogel nanocomposite was employed as a catalyst for the hydrogenation of p-nitrophenol with sodium borohydride in water. The rate of hydrogenation of p-nitrophenol was observed to be increased with the increased amount of catalyst as well as the temperature. The maximum reduction rate of p-nitrophenol was found as high as 0.26 min-1.

Comparative study of the effect of Cinnamomum zeylanicum extract and nanocomplex on some immunological and physiological parameters before and after MTX treatment loading

The current study aimed to know the protective effect of the aqueous extract of Cinnamon zeylanicum and the free Cinnamon nanocomplex loaded with MTX treatment to reduce the effect of arthritis induced with Complete Freunds (CFA Adjuvant) in male albino rats by studying some changes in immunological and histological parameters. Atomic force microscope (AFM) revealed the appearance of changes in the surface of nanocomposites loaded with treatment. The immunological results indicated that the induction of rheumatoid arthritis (RF) in male white G2 rats led to a significant increase (P<0.05) in the level of IL-8 cytokine concentrations 86.31 pg/ml compared with the negative control group at 24.41 pg/ml. There was also a significant decrease (P<0.05) in the level of IL-8 concentration in the G7 group dosed with cinnamon nanocomplex loaded with MTX treatment pg/ml (37.45) and the results of histological parameters showed that there was a significant increase in white blood cells in the positive control group G2 (14.00) compared to With the negative control group G1 (5.433), while in the group G7 there was a significant decrease (p<0.05) (9.433).

Remediation of water containing phosphate using ceria nanoparticles decorated partially reduced graphene oxide (CeO2-PRGO) composite

Phosphate pollution from point and discrete sources is a serious threat to the aquatic ecosystem in both industrialized and developing countries. The release of excessive amounts of phosphates into the river streams and lakes from agricultural runoffs, septic tanks and sewage system causes serious and widespread environmental problems. The present study investigated the preparation of cerium oxide partially reduced graphene oxide (CeO2-PRGO) nanocomposite and its applications as an efficient adsorbent to remediate water containing phosphate. The (CeO2-PRGO) nanocomposite was prepared via the modification of GO sheets with sodium dodecyl sulfate (SDS) followed by the nucleation of CeO2 nanoparticles onto the surface of SDS-GO nanosheets. The chemical structure and morphology of the CeO2-PRGO adsorbent were characterized using several analytical techniques including UV-Vis, FTIR, Raman, XRD, XPS, SEM, and TEM. The batch adsorption experiments for the removal of phosphate ions onto the surface of CeO2-PRGO revealed that the maximum adsorption capacity was 45.8 mg/g at pH = 4, initial concentration 100 ppm, dosage 1 g/L, contact time 150 min, and room temperature. CeO2-PRGO composite exhibited remarkable selectivity for phosphate in presence of interfering anions including Cl−, I−, and NO3− that exist widely in real water samples. The experimental data was explicated by the theoretical Langmuir adsorption isotherm module and the pseudo-second-order kinetic module. The experimental data fitted well with the modules (R2>99%) suggesting the adsorption of phosphate ions onto the surface of CeO2-PRGO nanocomposite take place through the generation of a monolayer of phosphate ions onto the surface of CeO2-PRGO. The adsorption mechanism was suggested to be an interaction between phosphate ions and Ce3+ sites on the surface of ceria nanoparticles on the adsorbent surface. The results showed that 100% of adsorbed phosphate ions can be regenerated by using 0.5 M NaOH and about 100% removal efficiency even after five adsorption-desorption cycles. Additionally, CeO2-PRGO composite can determine trace levels of phosphate in real water samples which acquire well for its promising in environmental applications.

Simple and affordable graphene nano-platelets and carbon nanocomposite surface decorated with cetrimonium bromide as a highly responsive electrochemical sensor for rutin detection

In this article, an economical, efficient, and unfussy nanocomposite sensor was equipped for the analysis of powerful antioxidant rutin (RTN). Due to the synergetic effect with more surface-active cites, cetrimonium bromide (CMB) was decorated on the surface of nanocomposite of graphene nano-platelets (GNPs) and carbon (CB) paste to attribute a superior electro-catalytic nature for RTN detection in phosphate buffer (PB) as a supporting electrolyte. The proposed CMB functionalized GNPs-CB composite paste electrode (CMB/GNPs-CBCPE) declining the material resistance and overpotential with rising the kinetic rate, peak currents, and material conductance towards the RTN detection. In the optimal experimental conditions, the analyzing efficiency of CMB/GNPs-CBCPE was examined using the linear sweep voltammetry (LSV), cyclic voltammetry (CV), and differential pulse voltammetry (DPV) with a finer linear relation andthe corresponding limit of detection (LOD) values are found to be 0.041 µM, 0.023 µM, and 0.0027 µM, respectively. The effect of some organic molecules and some metal ions on RTN detection at CMB/GNPs-CBCPE was studied with acceptable results. The sensitivity, selectivity, steadiness, repeatability, and reproducibility of the modified sensor were studied with decent results. The practicability of CMB/GNPs-CBCPE was verified by analyzing RTN in blood serum, urine, green tea, tomato, apple juice, and medicinal samples with adequate recoveries.

Synergistic effect of cementite amorphization and oxidation on forming a nanocomposite self-lubricating surface during sliding

The in situ formation of a self-lubricating surface is potentially valuable and greatly significant for reducing wear in many steel material applications, especially nanocomposite self-lubricating surfaces. Here, we discover a novel nanocomposite self-lubricating oxide surface composed of amorphous structures and oxide nanoparticles . The nanocomposite oxide structures and tribolayer on pearlite after dry sliding were characterized in detail by using spherical aberration transmission electron microscopy (TEM), and direct evidence of cementite amorphization was observed. Moreover, cementite interfacial amorphization was visualized, and the radial distribution function was calculated by a molecular dynamics (MD) simulation. Notably, high-resolution characterization and elemental distribution analyses were performed on an incompletely formed self-lubricating surface. The relationship between the amorphization and formation of nanocomposite oxides is explained in terms of friction strain, heat and oxygen intervention. After the cementite in the tribolayer is transformed into an amorphous structure, it becomes part of the wear debris formed due to dry sliding friction . Wear debris containing nanolamellar and amorphous structures is continuously transformed into oxide nanoparticles after being mechanically mixed, rolled and oxidized on the contact surface. Utilizing the in situ formation of nanocomposite oxide surfaces can further improve the tribological and wear properties of metal materials containing cementite structures.