Layered Potassium Titanium Niobate/Reduced Graphene Oxide Nanocomposite as a Potassium‑Ion Battery Anode

With graphite currently leading as the most viable anode for potassium-ion batteries(KIBs),other materials have been left relatively underexamined.Transition metal oxides are among these,with many positive attributes such as synthetic maturity,longterm cycling stability and fast redox kinetics.Therefore,to address this research deficiency we report herein a layered potassium titanium niobate KTiNbO5(KTNO)and its rGO nanocomposite(KTNO/rGO)synthesised via solvothermal methods as a high-performance anode for KIBs.Through effective distribution across the electrically conductive rGO,the electrochemical performance of the KTNO nanoparticles was enhanced.The potassium storage performance of the KTNO/rGO was demonstrated by its first charge capacity of 128.1 mAh g^(−1) and reversible capacity of 97.5 mAh g^(−1) after 500 cycles at 20 mA g^(−1),retaining 76.1%of the initial capacity,with an exceptional rate performance of 54.2 mAh g^(−1)at 1 A g^(−1).Furthermore,to investigate the attributes of KTNO in-situ XRD was performed,indicating a low-strain material.Ex-situ X-ray photoelectron spectra further investigated the mechanism of charge storage,with the titanium showing greater redox reversibility than the niobium.This work suggests this lowstrain nature is a highly advantageous property and well worth regarding KTNO as a promising anode for future high-performance KIBs.

Nanocomposite superstructure of zinc oxide mesocrystal/reduced graphene oxide with effective photoconductivity

Metal oxide mesocrystals are the alignment of metal oxide nanoparticles building blocks into the ordered superstructure,which have potentially tunable optical,electronic,and electrical properties suitable for practical applications.Herein,we report an effective method for synthesizing mesocrystal zinc oxide nanorods(ZnONRs).The crystal,surface,and internal structures of the zinc oxide mesocrystals were fully characterized.Mesocrystal zinc oxide nanorods/reduced graphene oxide(ZnONRs/rGO)nanocomposite superstructure were synthesized also using the hydrothermal method.The crystal,surface,chemical,and internal structures of the ZnONRs/rGO nanocomposite superstructure were also fully characterized.The optical absorption coefficient,bandgap energy,band structure,and electrical conductivity of the ZnONRs/rGO nanocomposite superstructure were investigated to understand its optoelectronic and electrical properties.Finally,the photoconductivity of the ZnONRs/rGO nanocomposite superstructure was explored to find the possibilities of using this nanocomposite superstructure for ultraviolet(UV)photodetection applications.Finally,we concluded that the ZnONRs/rGO nanocomposite superstructure has high UV sensitivity and is suitable for UV detector applications.

Synergism of Zinc Oxide/Organoclay-Loaded Poly(lactic acid) Hybrid Nanocomposite Plasticized by Triacetin for Sustainable Active Food Packaging

The synergistic effect of organoclay(OC)and zinc oxide(ZnO)nanoparticles on the crucial properties of poly(lactic acid)(PLA)nanocompositefilms was systematically investigated herein.After their incorporation into PLA via the solvent casting technique,the water vapor barrier property of the PLA/OC/ZnOfilm improved by a maximum of 86%compared to the neat PLAfilm without the deterioration of Young’s modulus or the tensile strength.Moreover,thefilm’s self-antibacterial activity against foodborne pathogens,including gram-negative(Escherichia coli,E.coli)and gram-positive(Staphylococcus aureus,S.aureus)bacteria,was enhanced by a max-imum of approximately 98–99%compared to the neat PLAfilm.Furthermore,SEM images revealed the homo-geneous dispersion of both nano-fillers in the PLA matrix.However,the thermal stability of thefilm decreased slightly after the addition of the OC and ZnO.Thefilm exhibited notable light barrier properties in the UV-Vis range.Moreover,the incorporation of a suitable biodegradable plasticizer significantly decreased the Tg and notably enhanced theflexibility of the nanocompositefilm by increasing the elongation at break approxi-mately 1.5-fold compared to that of the neat PLAfilm.This contributes to its feasibility as an active food packa-ging material.

Synthesis, properties, and applications of graphene oxide/reduced graphene oxide and their nanocomposites

Thanks to their remarkable mechanical, electrical, thermal, and barrier properties, graphene-based nanocomposites have been a hot area of research in the past decade. Because of their simple top-down synthesis, graphene oxide (GO) and reduced graphene oxide (rGO) have opened new possibilities for gas barrier, membrane separation, and stimuli-response characteristics in nanocomposites. Herein, we review the synthesis techniques most commonly used to produce these graphene derivatives, discuss how synthesis affects their key material properties, and highlight some examples of nanocomposites with unique and impressive properties. We specifically highlight their performances in separation applications, stimuli-responsive materials, anti-corrosion coatings, and energy storage. Finally, we discuss the outlook and remaining challenges in the field of practical industrial-scale production and use of graphene-derivative-based polymer nanocomposites.

Nickel Oxide/Carbon Nanotubes Nanocomposite for Electrochemical Capacitance

A nanocomposite of nickel oxide/carbon nanotubes was prepared through a simple chemical precipitation followed by thermal annealing. The electrochemical capacitance of this electrode material was studied. When the mass fraction of CNTs (carbon nanotubes) in NiO/CNT composites increases, the electrical resistivity of nanocomposites decreases and becomes similar to that of pure CNTs when it reaches 30%. The specific surface area of composites increases with increasing CNT mass fraction and the specific capacitance reaches 160 F/g under 10 mA/g discharge current density at CNT mass fraction of 10%.

Polyimide-silver nanocomposite containing phosphine oxide moieties in the main chain:Synthesis and properties

New flame-retardant polyimide-silver nanocomposite containing phosphine oxide moiety in the main chain was synthesized by a convenient ultraviolet irradiation technique.A precursor such as AgNO_3 was used as the source of the silver particles.Polyimide 6 as a source of polymer was synthesized by polycondensation reaction of bis（3-aminophenyl） phenyl phosphine oxide 4 with pyromellitic anhydride 5 in the presence of iso-quinoline as base and in m-cresol solution.The resulting composite film was characterized by FTIR spectroscopy,X-ray diffraction（XRD）,transmission electron microscopy（TEM）,thermogravimetry（TGA） and differential scanning calorimetry（DSC）.The average size of the nanometer Ag particles is about 10 nm.The temperature of 5 and 10%weight loss and also the char yield at 600℃of polyimide-silver nanocomposite 6a were higher than the pure PI 6.

Magnetic Fe_3O_4-Reduced Graphene Oxide Nanocomposites-Based Electrochemical Biosensing

An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application.

Effect of graphene oxide on the corrosion,mechanical and biological properties of Mg-based nanocomposite

This study investigates the effect of graphene oxide(GO)on the mechanical and corrosion behavior,antibacterial performance,and cell response of Mg–Zn–Mn(MZM)nanocomposite.MZM/GO nanocomposites with different amounts of GO(i.e.,0.5 wt%,1.0 wt%,and1.5 wt%)were fabricated by the semi-powder metallurgy method.The influence of GO on the MZM nanocomposite was analyzed through the hardness,compressive,corrosion,antibacterial,and cytotoxicity tests.The experimental results showed that,with the increase in the amount of GO(0.5 wt%and 1.5 wt%),the hardness value,compressive strength,and antibacterial performance of the MZM nanocomposite increased,whereas the cell viability and osteogenesis level decreased after the addition of 1.5 wt%GO.Moreover,the electrochemical examination results showed that the corrosion behavior of the MZM alloy was significantly enhanced after encapsulation in 0.5 wt%GO.In summary,MZM nanocomposites reinforced with GO can be used for implant applications because of their antibacterial performance and mechanical property.

Buckling analysis of embedded graphene oxide powder-reinforced nanocomposite shells

In this study,the buckling analysis of a Graphene oxide powder reinforced(GOPR)nanocomposite shell is investigated.The effective material properties of the nanocomposite are estimated through Halpin-Tsai micromechanical scheme.Three distribution types of GOPs are considered,namely uniform,X and O.Also,a first-order shear deformation shell theory is incorporated with the principle of virtual work to derive the governing differential equations of the problem.The governing equations are solved via Galerkin’s method,which is a powerful analytical method for static and dynamic problems.Comparison study is performed to verify the present formulation with those of previous data.New results for the buckling load of GOPR nanocomposite shells are presented regarding for different values of circumferential wave number.Besides,the influences of weight fraction of nanofillers,length and radius to thickness ratios and elastic foundation on the critical buckling loads of GOP-reinforced nanocomposite shells are explored.

Electro-conductive Nanocrystalline Cellulose Film Filled with TiO_2-ReducedGraphene Oxide Nanocomposite

Imparting electro-conductive properties to nanocellulose-based products may render them suitable for applications in electronics, optoelectronics, and energy storage devices. In the present work, an electro-conductive nanocrystalline cellulose （NCC） film filled with TiO2-reduced-graphene oxide （TiO2-RGO） was developed. Initially, graphene oxide （GO） was prepared using the modified Hummers method and thereafter photocatalytically reduced using TiO2 as a catalyst. Subsequently, an electro-conductive NCC film was prepared via vacuum filtration with the as-prepared TiO2-RGO nanocomposite as a functional filler. The TiO2-RGO nanocomposite and the NCC/TiO2-RGO film were systematically characterized. The results showed that the obtained TiO2-RGO nanocomposite exhibited reduced oxygen-containing group content and enhanced electro-conductivity as compared with those of GO. Moreover, the NCC flm flled with TiO2-RGO nanocomposite displayed an electro-conductivity of up to 9.3 S/m and improved mechanical properties compared with that of the control. This work could provide a route for producing electro-conductive NCC flms, which may hold signifcant potential as transparent ？exible substrates for future electronic device applications.

Hydrophobic and Magnetic Reduced Graphene Oxide Nanocomposite for Emulsified Oil Removal

Magnetic reduced graphene oxide(MRGO) nanocomposite was prepared by the chemical coprecipitation method and applied as adsorbent for removing emulsified oil from oily wastewater. SEM, TEM, XRD, FT-IR, VSM and other analytical methods were utilized to characterize the prepared MRGO. The adsorption performance of MRGO was evaluated under different initial adsorbate concentration, MRGO dosage, temperature, and pH value of the solution. The adsorption kinetics and isotherms were investigated. In addition, the MRGO repeatability was also tested. It was found that almost 65%of emulsified oil were removed by MRGO in the first 15 min. The MRGO adsorption capacity and efficiency for removal of adsorbate reached 335.85 mg/g and 92.52% within 60 min, respectively. The adsorption capacity reduced with an increasing MRGO dosage, while increased with the increase of emulsified oil concentration. The adsorption performance of MRGO in the alkaline environment was lower than that in the acidic environment. The adsorption data could well fit to the pseudosecondorder model. The Langmuir model could well describe the isotherm data. The MRGO adsorption capacity was still more than 236.1 mg/g at the sixth regeneration cycle.

Zinc oxide nanocomposites with antitumor activity

Zinc oxide nanocomposites in the form of coatings and composite films with antitumor activity were obtained by deposition of ZnO nanofilms on surfaces of ethyl ether Sali- cylidene DL-tyrosine (S1) and ethyl ether Sali- cylidene DL-tyrosine Cu (II) chelate (S2) by magnetron sputtering of Zn target. Ethyl ether salicylidene DL-tyrosine, Cu (II) chelate of ethyl ether salicylidene DL-tyrosine reveal some anticancer properties. Their zinc oxide nano- composites were obtained in the form of coat- ings (S1 + ZnO, S2 + ZnO) and composite films presenting a mixture of polyvinyl alcohol (PVA) with S1, S2 (S1 + PVA + ZnO, S2 + PVA + ZnO), for the purpose of increasing anticancer activity. Considerable increase in antitumor activity re- veal ZnO nanocomposites with salicylidene amino acid chelates (as distinct from their ethers) in the form of S2 + ZnO (47%) and S2 + PVA + ZnO (48%) in comparison with S2 (20%). Structural, spectral properties of the salicylidene amino acids and their ZnO nanocomposites were studied.

Malus domestica and Solanum lycopersicum Mixtures for the Synthesis of Graphene Silver and Zinc Oxide Nanocomposites

This study reports on the novel and simple green method involving the use of apple (Malus domestica) and tomato (Solanum lycopersicum) extracts in the synthesis of electroactive layers of silver nanoparticles|graphene oxide (AgNPs|GO) and zinc oxide nanoparticles|graphene oxide (ZnONPs|GO). The surface morphology of the green synthesized nanocomposites was studied using High-Resolution Transmission Electron Microscopy (HRTEM), High-Resolution Scanning Electron Microscopy (HRSEM) while the elemental analysis was studied using Fourier Transform Infrared Spectroscopy (FTIR), Raman spectroscopy and X-Ray diffraction (XRD) and their optical properties were further characterised using Ultraviolet Spectroscopy (UV-vis). The electrochemical studies of these nanocomposites were achieved using cyclic voltammetry (CV) where an increase in electron conductivity of the AgNPs|GO and ZnONPs|GO nanocomposite was observed. Comparatively, the silver nanoparticulate-based platforms were observed to have superior electrochemical properties as opposed to the zinc oxide-based platform. The observed electrochemical activities of the synthesized nanocomposites are a good indication of their suitability as electroactive platforms towards the development of electrochemical sensors. Electrochemical sensors are popular in the Electrochemistry field because they may be developed using different methods in order to suit their intended analytes. As such, the synthesis of a variety of electrochemical platforms provides researchers with a vast range of options to select from for the detection of analytes.

Effect of the Addiction of Metal Oxide Nanoparticles on the Physical, Chemical and Thermal Properties of PVA Based Nanocomposites

In this study, poly(vinyl alcohol) (PVA)-based nanocomposites consisting of metallic oxide nanoparticles (TiO2, ZnO, ZrO2) were obtained from an aqueous solution of 7% PVA, in order to compare the microstructural, and physical properties of bionanocomposite films reinforced with various loading contents (0.1%, 0.2% and 0.3% w/w). They were evaluated regarding their molecular toughness through Nuclear Magnetic Resonance (NMR), regarding their chemical structural through Fourier Transform Infrared Spectroscopy (FTIR), regarding their crystallinity throught X-ray Diffraction (XRD), and regarding termal properties through Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The NMR results showed that the smallest concentrations of these oxides have a tendency to disperse better in the polymeric matrix, improving the structural toughness. Besides, changes in the termal resistance of the material were found with the use of TGA and DSC.

PVP/Clay/Vanadium Oxide Nanocomposites Development and Characterization for Potential Use as Controlled Drug Release Matrix in Diabetes’ Treatment

Research in drug release field, nowadays, focuses on more efficient systems for better release of the drug and wider timespan of action, granting several benefits to the patient’s organism and to the industry. The present work aims on developing a matrix of polymer nanocomposite based on Polyvinylpyrrolidone (PVP), bentonite clay and two different vanadium oxides, via spray drying technique. The goal is to achieve a long and steady release of metformin hydrochloride in future formulations with this drug. Since either the nanocomposites or metformin hydrochloride is highly hydrophilic, it is most suited for a future formulation of tablets. For now, the nanocomposites obtained were characterized through Nuclear Magnetic Resonance (NMR), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR). The SEM and XRD analysis portrayed a very amorphous and homogenized material. TGA and FTIR proved the insertion of the nanoparticles, thus granting to the new material a slightly higher thermal resistance. The NMR analysis, using T1H parameters, is key for determining the formulations would behave better for extending the resistance of the nanocomposite’s matrix with the drug in later dissolution of tablets.

The Effect of Titanium Dioxide and Zinc Oxide Nanoparticles on Some Mechanical Properties of Epoxy Nanocomposites： A Comparative Study

A new type of inorganic-polymer materials of epoxy Titanium Dioxide and Zinc Oxide was prepared. In this work, the mechanical properties of polymer composites reinforced with ceramic nanoparticles were investigated. Three points bending tests demonstrated an enhancement in flexural strength and flexural modulus respectively, compared to the pure epoxy. The reinforcement of nanoparticulate materials was Titanium Dioxide and Zinc Oxide with various weight fraction. Experimental tests results indicated that the composite materials have significantly higher modulus of elasticity than the matrix material. It was found that the enhancement in modulus of elasticity was directly proportional to the weight fraction of reinforcement material, and that Zinc Oxide composites have higher modulus of elasticity than Titanium Dioxide composites with equivalent of weight fraction. The wear results showed that nanoparticles improved the wear resistance of epoxy nanocomposites, the Titanium Dioxide matrix particles could improve the wear resistance of the epoxy more efficiently than Zinc Oxide particles. The fatigue test showed that the fatigue resistance of epoxy Zinc Oxide matrix particles was higher than that of Titanium Dioxide matrix particles.

Preparation and oxidation behaviour of electrodeposited Ni-CeO_2 nanocomposite coatings

Ni-CeO2 nanocomposite coatings with different CeO2 contents were prepared by codeposition of Ni and CeO2 nanoparticles with an average particle size of 7 nm onto pure Ni surfaces from a nickel sulfate. The CeO2 nanoparticles were dispersed in the electrodeposited nanocrystalline Ni grains （with a size range of 10-30 nm）. The isothermal oxidation behaviours of Ni-CeO2 nanocomposite coatings with two different CeO2 particles contents and the electrodeposited pure Ni coating were comparatively investigated in order to elucidate the effect of CeO2 at different temperatures and also CeO2 contents on the oxidation behaviour of Ni-CeO2 nanocomposite coatings. The results show that the as-codeposited Ni-CeO2 nanocomposite coatings have a superior oxidation resistance compared with the electrodeposited pure Ni coating at 800 °C due to the codeposited CeO2 nanoparticles blocking the outward diffusion of nickel along the grain boundaries. However, the effects of CeO2 particles on the oxidation resistance significantly decrease at 1050 °C and 1150 °C due to the outward-volume diffusion of nickel controlling the oxidation growth mechanism, and the content of CeO2 has little influence on the oxidation.

Oxidation and hot corrosion of electrodeposited Ni-7Cr-4Al nanocomposite

A Ni-7Cr-4Al（mass fraction, %） nanocomposite was fabricated by co-electrodeposition of Ni with Cr（40 nm） and Al（100 nm） nanoparticles from a nickel sulfate bath, and its oxidation at 800 °C in air and hot corrosion under molten 75% Na2SO4 ＋ 25% Na Cl salts（mass fraction） at 750 °C were investigated. For comparison, Ni-11 Cr nanocomposite and Ni-film were also investigated in order to elucidate the effect of Cr nanoparticles. The results indicate that Cr and Al nanoparticles are dispersed in the electrodeposited nanocrystalline Ni grains（in size range of 20-60 nm）. Ni-7Cr-4Al nanocomposite exhibits a dramatically increased oxidation resistance compared with Ni-11 Cr nanocomposite and Ni-film due to the fast formation of alumina scale, which also improves its hot corrosion resistance under molten 75% Na2SO4 ＋ 25% Na Cl salts.

Effect of annealing treatment on cyclic-oxidation of electrodeposited Ni-Al nanocomposite

An electrodeposited Ni-Al nanocomposite having a nanocrystalline Ni matrix dispersing Al nanoparticles was annealed in vacuum at 500 ℃ for different time （3, 5 and 8 h, respectively）. The results show that the annealing treatment leads to the reaction of Ni and Al to form intermetallics and the coarsened Ni grains that are doped with a certain amount of Al atoms diffused from the nanoparticles. Cyclic oxidation in air at 1 000 ℃ indicates that the scale spallation resistance of the annealed Ni-Al nanocomposite increases with the increase of annealing time, due to prevention of the composite intergranular cracking during the cycling, reduction of numerous surface NiO nodules formed on the scale spalled area and prevention of internal oxidation.

Surface Oxidation of Al_2O_3/SiC Nanocomposite: Phase Transformation and Microstructure

The surface oxidation behavior of pressureless sintered Al2O3/SiC nanocomposite was studied from 1000 to 1400 ℃ for more than 10 h in air. Weight gain during the process of heat treatment was measured by TG analysis. Phase transformation and microstructure changes of these specimens due to oxidation were investigated with X-ray diffraction （XRD）, SEM and EDX technology. Thermogravimetric analysis show that the weight gain as a result of oxidation of SiC become significant above 1200 ℃. In the range of 1000 - 1300 ℃, the SiC grits are usually coated with a layer of amorphous silica after oxidation. Above 1300 ℃, the amorphous silica reacted with alumina matrix and formed mullite or crystallized into cristobalite. The rate of oxidation depends on the formation of dense cristobalite film. Large amount of needle-like mullite and alumina crystals are formed on the surface after oxidation at 1400℃.