Oxide Nanotubes Research Articles

Quantitative evaluation of trace ritonavir in serum by versatile SERS substrate based on silver-decorated hollow reduced graphene oxide/zinc oxide nanotubes

Because of its fascinating molecular fingerprint identification ability and high sensitivity, surface-enhanced Raman scattering (SERS) shows an attractive application prospect in the clinical monitoring of blood drug concentration and efficacy judgment. In this study, a quantitative SERS-based detection of ritonavir in serum sample was conducted by developing silver (Ag)-decorated zinc oxide (ZnO)@reduced graphene oxide (rGO) nanotubes. Taking advantage of the efficient light absorption and molecular enrichment capabilities of hollow rGO-modified ZnO nanotubes with high specific surface area, an extremely low limit of detection (LOD) value of 466.7 pg/mL was achieved for ritonavir owing to the synchronous electromagnetic and chemical enhancement after the participation of Ag islands. Such a detection was carried out in a recyclable mode based on the intrinsic photocatalytic activity of ZnO, which was ascribed to the Ag and rGO-mediated effective separation of photo-induced electron-hole pairs. A practical SERS-based monitoring of ritonavir was finally facilitated in serum, demonstrating high recovery rates varied from 82.1% to 89.7%. Such a novel metal-semiconductor SERS sensor with ideal biocompatibility and sensitivity is promising in drug diagnostics.

Solar-light-sensitive applications of recycled iron oxyhydroxide as photoelectrolytic heterostructure by encapsulating in reduced graphene oxide and titanium oxide nanotube array (FeOxrGO/TiNTA)

FeOxrGO/Ti photoanodes by decorating TiO2 nanotube array (TiNTA) with waste iron oxide and reduced graphene oxide (rGO) were synthesized via wet impregnation and calcination. Photoelectrocatalytic (PEC) degradation of azo dye pollutants, accompanied by hydrogen gas evolution, was demonstrated in a dual-chamber divided cell. Characterization showed that the iron oxide recovered from the wastewater treatment plant were crystalline clusters consisting of mineral goethite nanoparticles (αFeOOH NPs) with a visible-light responsive bandgap. Furthermore, the incorporation of rGO led to an enhancement in the electrochemical surface area (ECSA, cm2) of the anode due to its larger capacitive current compared to TiNTA. This improvement facilitated the transport of charge carriers (e- and h+) within a type-II heterostructure of αFeOOH and TiO2. The applied bias photon-to-current conversion efficiency and transient photocurrent density, depending on the composition of iron oxide in FeOxrGO/Ti, substantially increased. 2%wt of iron oxide in FeO2.0rGO/Ti has been optimized in terms of azo dye decolorization, TOC removal, and H2 generation rates (on Pt/G cathode) in 0.1 M Na2SO4 at a working potential of +1.0 V (vs. Ag/AgCl). This study explored the reusability and valorization of Fenton fluidized-bed waste iron oxide with TiO2 for PEC applications.

Insights into the thermal attributes of sodium alginate (NaC6H7O6) based nanofluids in a three-dimensional rotating frame: A comparative case study

The present work distinguishes the thermal attributes of zirconium oxide (ZrO2) and single wall-carbon nanotubes (SWCNTs) in a three dimensional rotating frame under the magnetic field environment. Sodium alginate (NaC6H7O6) is assumed to be the base fluid. The slippage and convective conditions on boundary have also been incorporated. The analysis comprehends, comparatively, features of both SWCNTs-NaC6H7O6 and ZrO2–NaC6H7O6 nanofluids. The amalgamation of nanomaterial SWCNTs-ZrO2 in sodium alginate builds up the thermal characteristics. An algorithmic approach deals with the approximate solutions of the problem. The numerical algorithm is mainly based on order reduction and central difference discretization. A comparison, in limiting case, appraises the proficiency of the code. The outcomes are physically and numerically interpreted via graphical and tabular representations against the prime parameters. The nano-composition of SWCNTs-ZrO2 convincingly improves and embellishes the heat transport rate. It has been revealed from the results that higher the microrotation parameter Ω0, higher will be the thermal boundary layer thickness in both cases of nanofluids such as SWCNTs/NaC6H7O6 and ZrO2/NaC6H7O6. A sensible judgment of the outcomes discloses that SWCNTs possess, comparatively, better heat transfer features than zirconium oxide.

High-Performance Multifunctional Shape Memory Epoxy with Hybrid Graphene Oxide and Carbon Nanotube Reinforcement

High-Performance Multifunctional Shape Memory Epoxy with Hybrid Graphene Oxide and Carbon Nanotube Reinforcement

Synthesis of carbon nanotube-iron oxide composites via combustion waves for hybrid Li-ion battery anodes

The design and synthesis of suitable transition metal oxide (TMO) with carbonaceous material are crucial to produce high-performance anodes for Lithium-ion batteries (LIBs). Here, we show a facile synthesis method for iron oxide and carbon nanotube (CNT) composite via CNT-guided combustion waves. The combustion waves propagate through a freestanding film composed of multi-walled CNTs (MWCNTs), iron nitrate, and combustible nitrocellulose, synthesizing the composite in one-pot within a few seconds. The resulting composite consists of MWCNT networks encapsulating iron oxide submicron particles (CFs). The composite electrode employing optimized CFs provides exceptional initial specific capacity and rate capability (792 mAh/g at 0.1C and 588 mAh/g at 5C) and an increased capacity of 1215 mAh/g after 500 charge–discharge cycles at 1C. The morphological and electrochemical characterization reveal pulverized nanoparticles encapsulated within MWCNT networks, entailing hybrid capacities of redox conversion and pseudocapacitance. This facile synthesis method for TMO–MWCNT composites provides a feasible family of low-cost composite electrodes for high-performance LIBs.

Synergistic influence of carbon nanotube-graphene oxide hybrid and nanosized interfacial TiC on the mechanical performance of Cu matrix composites

Reinforcement architecture and interfacial structure are two key factors affecting the performance of composites. Herein we attempted to achieve a comprehensive improvement of mechanical properties of carbon nanomaterials (CNMs) reinforced Cu matrix composites by means of reinforcement structure construction and interface structure optimization. Graphene oxide (GO) and acid-treated carbon nanotubes (AT-CNTs) were self-assembled into a GO-CNT hybrid structure through an ultrasonic mixing method, and then used as reinforcement of Cu matrix composite through the powder metallurgy method. The strengthening efficiency of GO-CNT hybrid was significantly higher than that of individual CNTs or GO, which could be attributed to the stable interconnected architecture of GO-CNT hybrid formed through sp3 hybridized C–C bonds and the larger interfacial area between them and Cu matrix. In addition, aiming at the issue of poor interfacial adhesion between the GO-CNT hybrid and Cu matrix, TiC nanoparticles were introduced onto the surface of GO-CNT hybrid through a pressureless spark plasma sintering strategy. The TiC nanoparticles can improve the interfacial wettability and optimize the interfacial bonding state. TEM results confirmed a semi-coherent interfacial lattice matching relationship between TiC nanoparticles and Cu matrix, which was conducive to forming robust interfacial bonding. Through the construction of hybrid reinforcement and the introduction of nanosized interfacial TiC, the GO-CNT hybrid reinforced Cu matrix composite has obtained ultra-high strengthening efficiency, and exhibited satisfied combination of strength and ductility. This study can provide a referential strategy for the comprehensive performance optimization of CNMs reinforced metal matrix composites.

Core-shell structured Si@Cu nanoparticles segregated in graphene-carbon nanotube networks enable high reversible capacity and rate capability of anode for lithium-ion batteries

The volume expansion of Si electrodes and the poor conductivity of Si as well as the repeated rupture of solid electrolyte interface (SEI) lead to the rapid capacity decay of Si-based anode Li-ion batteries. The rational design of anode materials for the above problems is considered an effective solution. In this work, core-shell structured Si@Cu nanoparticles segregated in graphene-carbon nanotube networks (Si@Cu/CNT/rGO) is constructed by one-step hybrid and reduction self-assembly strategy. First, metallic copper was coated on silicon nanoparticles to improve the reaction kinetics of the cell during operation. The flexible reduced graphene oxide and rigid carbon nanotube are designed as a network structure for increasing the electrical conductivity and mechanical strength of the electrode material. This design not only provides sufficient buffering space for the volume change during cell operation, but also improves the electron migration effect of the composite Si@Cu/CNT/rGO. Thanks to this design, the composite electrode maintains a high lithium storage capacity of 1915.5 mAh/g (130 cycles) and 1486.7 mAh/g (200 cycles) after charging and discharging at 100 mA g−1 and 1000 mA g−1, respectively.

RETRACTED ARTICLE: Fabrication of Molecularly Imprinted Polymer Films Based on Graphene Oxide and Carbon Nanotubes for Nitrogenous Compound Sensing in Fuel Chemicals

RETRACTED ARTICLE: Fabrication of Molecularly Imprinted Polymer Films Based on Graphene Oxide and Carbon Nanotubes for Nitrogenous Compound Sensing in Fuel Chemicals

Influence of synthesized nanomaterials in the strength and durability of cementitious composites

The development of high-performance materials has been prompted by a constantly expanding infrastructure with complex technical constraints. Performance modification of cement composites using nanoparticles has been thoroughly researched to address demands in the construction industry. This cutting-edge review examines the various parameters of cement composites, such as fresh properties, mechanical properties, and durability characteristics that can be improved using synthesized nanomaterials such as nano-SiO2, nano-Al2O3, graphene oxide, and carbon nanotubes, as well as their inherent limitations. Based on the detailed review, the ideal replacement levels of nano-SiO2 (1–4 wt%), nano-Al2O3 (1–3 wt%), graphene oxide (0.05–0.1 wt%), and carbon nanotubes (0.1–0.5 wt%) can be recommended for the practical applications. It has been noted that the addition of synthesized nanomaterials tends to lower the workability of cement composites. However, nanoalumina, graphene oxide, nano-silica, and carbon nanotubes improve mechanical qualities such as compressive strength, flexural strength, and resistance to abrasion of the blended cementitious system at an optimum replacement level. Similarly, resistance against chemical attacks was imporved with the addition nano-silica, while the addition of graphene oxide in cement is more effective against chloride migration and fire exposure. The overall effect of synthesized nanomaterials is also compared in the study.

Human and environmental impacts of nanoparticles: a scoping review of the current literature

Use of nanoparticles have established benefits in a wide range of applications, however, the effects of exposure to nanoparticles on health and the environmental risks associated with the production and use of nanoparticles are less well-established. The present study addresses this gap in knowledge by examining, through a scoping review of the current literature, the effects of nanoparticles on human health and the environment. We searched relevant databases including Medline, Web of Science, ScienceDirect, Scopus, CINAHL, Embase, and SAGE journals, as well as Google, Google Scholar, and grey literature from June 2021 to July 2021. After removing duplicate articles, the title and abstracts of 1495 articles were first screened followed by the full-texts of 249 studies, and this resulted in the inclusion of 117 studies in the presented review.In this contribution we conclude that while nanoparticles offer distinct benefits in a range of applications, they pose significant threats to humans and the environment. Using several biological models and biomarkers, the included studies revealed the toxic effects of nanoparticles (mainly zinc oxide, silicon dioxide, titanium dioxide, silver, and carbon nanotubes) to include cell death, production of oxidative stress, DNA damage, apoptosis, and induction of inflammatory responses. Most of the included studies (65.81%) investigated inorganic-based nanoparticles. In terms of biomarkers, most studies (76.9%) used immortalised cell lines, whiles 18.8% used primary cells as the biomarker for assessing human health effect of nanoparticles. Biomarkers that were used for assessing environmental impact of nanoparticles included soil samples and soybean seeds, zebrafish larvae, fish, and Daphnia magna neonates.From the studies included in this work the United States recorded the highest number of publications (n = 30, 25.64%), followed by China, India, and Saudi Arabia recording the same number of publications (n = 8 each), with 95.75% of the studies published from the year 2009. The majority of the included studies (93.16%) assessed impact of nanoparticles on human health, and 95.7% used experimental study design. This shows a clear gap exists in examining the impact of nanoparticles on the environment.

Efficient detection of metronidazole by a glassy carbon electrode modified with a composite of a cyclotriveratrylene-based metal–organic framework and multi-walled carbon nanotubes

Constructing a sensitive and efficient sensor for determination of metronidazole (MNZ) is crucial in food field. Herein, a new cyclotriveratrylene-based metal–organic framework (MOF), namely, [Cd6L2(cyclen)2(H2O)2] (1), was constructed by self-assembly of functionalized 5,6,12,13,19,20-hexacarboxy-propoxy-cyclotriveratrylene (H6L), 1,4,7,10-tetraazacyclododecane (cyclen) and Cd(II) cation under solvothermal condition. In 1, adjacent Cd(II) cations are linked by L6− to produce a 2D polymeric structure with carboxylate and phenolic oxygen atoms. To enhance conductivity of 1, it was combined with conducting carbon materials, including mesoporous carbon (MC), reduced graphene oxide (RGO) and multi-walled carbon nanotubes (MWCNT), respectively, producing a series of composite materials. Remarkably, electrochemical tests showed that 1@MWCNT(1:1) featured a much better electrochemical detection performance for metronidazole (MNZ) than 1@MC and 1@RGO. The linear range for the detection of MNZ is up to 0.4–500 μM and the limit of detection (LOD) for MNZ reached 0.25 μM. Importantly, the fabricated sensor 1@MWCNT(1:1) was employed for the detection of MNZ in honey and egg with satisfactory result. High-performance liquid chromatography (HPLC) validated the high accuracy of the electrochemical method for the determination of honey and egg.

Structural and electronic properties of double-walled zigzag and armchair Zinc oxide nanotubes

• Stability and electronic properties of DWZnONTs based on DFT investigated. • (4,4)@(n,n) and (5,5)@(n,n) and (7,0)@(n,0) and (6,0)@(n,0) DWZnONTs considered. • (n,n)@(n+5,n+5) and 8, (n,0)@(n+8,0) with inter-wall distance of about 4.6 and 4.3 Å are the most stable structures. • All zigzag and armchair nanotubes are semiconductors having a direct bandgap. • Bandgap increases by increasing inner and outer tube diameters and inter-wall distances. • The bandgap of double-walled ZnO nanotubes is smaller than that of their single-walled nanotubes. In this paper, we have investigated the stability and electronic properties of double-walled ZnO nanotubes (DWZnONTs) based on density functional theory (DFT) with the SIESTA package. The calculation have been performed on the armchair (4,4)@(n,n) and (5,5)@(n,n) DWZnONTs with (n=9 to15) and the zigzag (7,0)@(n,0) and (6,0)@(n,0) with (n=14 to 20). The stability calculation of DWZnONTs shows that the armchair and the zigzag DWZnONTs with difference chirality of 5, (n,n)@(n+5,n+5) and 8, (n,0)@(n+8,0) and inter-wall distance of about 4.6 and 4.3 Å are the most stable structures, respectively. Considering the electronic band structure points that all zigzag and armchair nanotubes are semiconductors having a direct bandgap. Moreover, it is revealed that the value of the bandgap increases by increasing inner and outer tube diameters and inter-wall distances, and the process of change at higher inter-wall distances be almost constant. Our results show that the inter-wall coupling diminishes the energy gap in semiconducting DWZnONTs. We found that the energy gap of DWZnONTs depends on the structure of the inner and outer walls. The consequences of this investigation can certainly be helpful in future experimental studies.

Synergistic influence of MWCNTs/RGO on low-velocity impact response and mechanical properties of carbon fiber/epoxy composite

Nanoparticles can be used to enhance and improve the mechanical properties and low-velocity impact response of carbon fiber-reinforced polymer (CFRP) composites both simultaneously and individually. Also, the synergistic influence of two nanoparticles can be improved the mechanical properties and low-velocity impact response of CFRP composites. In this paper, the effects of reduced graphene oxide (RGO) and multi-walled carbon nanotubes (MWCNTs) on the mechanical properties, low-velocity impact response and damage area of epoxy/fiber carbon composites are investigated both simultaneously and individually. Composite specimens are fabricated with 0.4 weight percentages (wt.%) of RGO, 0.06 wt.% of MWCNTs individually, and a combination of RGO and MWCNTs with 0.6 and 0.06 wt.%, respectively. For comparison of the results, the neat epoxy specimens are fabricated and also tested. Direct homogenization technique is applied for preparation of nanocomposite mixture and then each layer of carbon fiber reinforced nanocomposite is fabricated using a hand lay-up process. Tensile modulus, tensile strength, variations of load, displacement, velocity, and absorbed energy of specimens versus time are obtained. For specimens with MWCNTs/RGO tensile modulus and tensile strength increased by about 21.30% and 17.12%, respectively, and the load peak increased by 15.15% at 1 J, 13.35% at 2 J, 39.62% at 3 J, and 39.62% at 3 J. It is concluded that the synergistic influence of MWCNTs and RGO on the results is more significant and has a higher effect on the impact responses. After the impact tests, Optical microscopy and SEM method are used to analyze fracture surfaces.

The Comparative Toxic Impact Assessment of Carbon Nanotubes, Fullerene, Graphene, and Graphene Oxide on Marine Microalgae Porphyridium purpureum.

The growing production and application of carbon-based nanomaterials (CNMs) represent possible risks for aquatic systems. However, the variety of CNMs with different physical and chemical properties and different morphology complicate the understanding of their potential toxicity. This paper aims to evaluate and compare the toxic impact of the four most common CNMs, namely multiwalled carbon nanotubes (CNTs), fullerene (C60), graphene (Gr), and graphene oxide (GrO) on the marine microalgae Porphyridium purpureum. The microalgae cells were exposed to the CNMs for 96 h and measured by flow cytometry. Based on the obtained results, we determined no observed effect level (NOEL), and calculated EC10 and EC50 concentrations for growth rate inhibition, esterase activity, membrane potential, and reactive oxygen species (ROS) generation changes for each tested CNM. According to the sensitivity (growth rate inhibition) of P. purpureum, the used CNMs can be listed in the following order (EC50 in mg/L, 96 h): CNTs (2.08) > GrO (23.37) > Gr (94.88) > C60 (>131.0). The toxicity of CNTs was significantly higher than the toxic effect of the other used CNMs, and only this sample caused an increase in ROS generation in microalgae cells. This effect was apparently caused by the high affinity between particles and microalgae associated with the presence of exopolysaccharide coverage on P. purpureum cells.

Magnesium oxide nanotube as novel strategies to enhance the anticancer activity of 5-Fluorouracil

We evaluated the adsorption process and anti-cancer activity of functionalized magnesium oxide nanotube (MgONT) adsorbed with 5-Fluorouracil (5-FU) in vacuum and solution (water and toluene) phases via density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. 5-FU is chemisorbed preferentially by oxygen and hydrogen atoms to Mg and O atoms at the end tube (state III) with adsorption energies of approximately −2.01 eV (vacuum), −1.72 eV (water), and −1.84 eV (toluene) by the Perdew-Burke-Ernzerhof (PBE) functional and 6-311+G** standard basis set. TDDFT methods illustrated that the maximum optical absorption by the CAM-B3LYP method is in the UV region with an energy of 4.57 eV and a maximum absorption at 271.36 nm. Analysis of molecular docking illustrated that the interaction of 5-FU, as antineoplastic agent, with Mg and O atoms of the nanotube via its O- and H-atoms can enhanced inhibitory effects against Human Epidermal growth factor Receptor 2 (HER2) and Epidermal growth factor receptor (EGFR). The results illustrated that 5-FU/MgO complex could be useful for the development of novel anti-cancer agents to treat breast cancer patients.

Aluminosilicatehalloysite nanotubes as a tool of modern nanocomposites for food safety

Nanoscale natural clay minerals, which include Si, O, Al, and Mg, are a class of environmentally safe inorganic materials with unique structures and diverse morphologies, including nanorods, nanofibers, and nanotubes. Aluminosilicatehallusite nanotubes (HNTs) are relatively new objects of research in materials science, they have a number of environmental and economic advantages compared to carbon nanotubes (CNTs), as well as fullerene and graphene. Natural halloysites are an order of magnitude cheaper than their synthetic counterparts. The location of halloysite is quite common, for example, in the KryvyiRih region and other places in other countries. Due to their high environmental friendliness and bioavailability, HNTs can be used in medicine, including as drug carriers with controlled release. HNTs can also exhibit (photo) catalytic properties, have high adsorption properties in relation to heavy metals Cu(II), Pb(II), Cd(II), Zn(II), Cr(IV) and Co(II) and solutions, containing dyes, pesticides and some other organic pollutants, as well as toxic gases (ammonia, hydrogen sulfide). HNTs in combination with other metals, such as Mn, Ti, acquire various practical applications. HNTs were introduced to ensure better functional photo(electro)catalytic properties of composites that can be a substrate, especially in the case of nanotube oxide decoration. For example, titanium, a white pigment, non-toxic, is included in the list of food additives and is designated as E171. Contained in food products: candies, cookies, cakes, chicken fillet, crab sticks, chewing gum, chocolate products. Although the addition of titanium dioxide in food products is permitted by many official documents, there is insufficient data in the scientific literature regarding the potential danger of titanium dioxide to the human body. Increased interest in TiO 2 is due to its high photocatalytic activity, which allows to realize processes of destruction of organic compounds, including ecotoxicants, into safe products. HNTs, or materials based on them, have found many useful applications in the treatment of drinking water and industrial wastewater. The structural features of HNTs make it possible to obtain new composite materials based on them, such as, for example, imohalite nanotubes (INTs) of a wide functional purpose and to determine the physicochemical patterns of their formation. Therefore, the relevance of the work lies in the combination of hallusite nanotubes and titanium dioxide as composite materials using electrosynthesis, and the analysis of the influence of the phase composition, photocatalytic activity of the composite material on the safety of its practical use, including in the food industry. Key words: aluminosilicates, nanotubes, nanomaterials, inner surface, safety, halluasite, titanium dioxide, composites, nanocomposites, synthesis.

Alanine aminotransferase detection using TIT assisted four tapered fiber structure-based LSPR sensor: From healthcare to marine life

Alanine aminotransferase (ALT), a type of inactive enzyme largely present in fish liver cells, is essential for the tricarboxylic acid (TCA) cycle. Monitoring ALT activity in the blood/hepatocellular layer has been demonstrated to be a sensitive sign of liver dysfunction and an essential method for determining the health status of fish. This study details the development of a multi-layer material (hybrids of graphene oxide and multi-walled carbon nanotubes (GO/MWCNTs), gold nanoparticles (AuNPs), and glutamate oxidase (GluOx) enzyme) immobilized localized surface plasmon resonance based unique fiber structure biosensor for the quantitative determination of ALT biomolecules at concentrations ranging from 0 to 1000 U/L. For this kind of detection, a novel taper-in-taper with four tapered (TIT4T) structure based on single-mode fiber has been developed. In addition to AuNPs, GO/MWCNTs were immobilized in the probe's sensing region to increase its LSPR efficiency and sensitivity. Synthesis of AuNPs was carried out utilizing the Turkevich method. The selectivity of the sensor is ensured by the effective immobilization of GluOx on the surface treatment. The linearity of sensor is in the range of 0–1000 U/L, whereas the sensitivity, limit of detection, and detection time are individually found at 7.5 p.m./(U/L), 4.84 U/L and 20 min, respectively. After evaluating the prospective applications of the sensors, the sensors' reusability, reproducibility, stability, pH test, and selectivity have all been found to be satisfactory. Proposed fiber optic biosensors have high sensitivity, robustness, reliability, fast detection, no electromagnetic interference, low cost, real-time monitoring, and biocompatible.

Effect of Weight Ratio of Graphene Oxide and Carbon Nanotubes on Electrochemical Performance of Planar On-Chip Micro-Supercapacitors

With the wide popularization of 5 G network, the application of miniaturized electronic equipment is being gradually developed, but limited by energy storage technology. Micro-supercapacitors (MSCs) have become the possible direction to solve this problem because of their unique properties. Graphene oxide and carbon nanotubes are very suitable materials for preparing MSCs. However, graphene oxide will overlap due to van der Waals force, and carbon nanotubes will be entangled. In order to solve these problems, reduced graphene oxide and carbon nanotube composite films were prepared by liquid-air interface self-assembly and hydroiodic acid reduction. Planar MSCs with weight ratios of 5:1, 10:1 and 15:1 were prepared by photolithography, and the MSCs of 15:1 show the best comprehensive performance with the area capacitance of 0.905 μF cm−2, the energy density of 0.125 nWh cm−2, the power density of 2263.31 nW cm−2, the time constant of 38 ms, and the capacitance retention of 91.2%.

Microstructure, properties and synergetic effect of graphene oxide-functionalized carbon nanotubes hybrid reinforced copper matrix composites prepared by DC electrodeposition

As the prospective carbon materials, graphene oxide (GO) and carbon nanotubes (CNTs) have attracted extensive attention in the fabrication of copper matrix composites (CMCs), but how their orientation and synergetic effect in Cu matrix affects the properties of composites has not been explored systematically. Herein, an efficient route to fabricate CMCs with GO-CNTs hybrid reinforcement had been reported, as well as the influence of different carbon reinforcement and different current densities on the texture orientation, microstructure and the comprehensive performance were investigated. From ultraviolet–visible results, it was found that one-dimensional CNTs bridge adjacent two-dimensional GO through π-π bonding to form an interconnected network structure. By adding GO-CNTs hybrid reinforcement to pure Cu sulfate, the preferred crystalline orientation of the GO-CNTs/Cu had been changed and a preferred orientation of (111) crystal plane was formed. Meanwhile, the EBSD results revealed that the GO-CNTs hybrid reinforcement had significant grain refinement effect and the average grain size of GO-CNTs/Cu composite reduced to 112 nm. According to TEM images, the lattice stripes between GO and CNTs indicate the formation of C–C covalent bonding. Owing to the synergistic effect and the C–C covalent bonding between GO and CNTs, the highest thermal conductivity reached to 527 W m−1 K−1, while, the highest hardness was up to 226.8 HV0.1, the friction coefficient reduced to 0.62and excellent corrosion resistance of the GO-CNTs/Cu composite were also achieved. This study suggested that the promising fabrication of high-oriented GO-CNTs/Cu composite may have the potential to obtain excellent performance.

Planar on-chip micro-supercapacitors based on reduced graphene oxide and carbon nanotube by liquid–air interface self-assembly and photolithography

Recently, the development of miniaturized electronic devices has accelerated the demand for the rate capability of planar on-chip micro-supercapacitors (POMSs). The POMSs based on reduced graphene oxide and carbon nanotube (rGO/CNT) composite electrodes (rGO/CNT-POMSs) were manufactured in the work and detailed electrochemical tests of devices were carried out over a wide range of scanning rates (0.01–10000 V s−1). The rGO/CNT composite electrode films without binder were prepared on silicon substrates by a modified liquid–air interface self-assembly method and a hydroiodic acid reduction method. The electrodes were fabricated into interdigital structure with 50 μm width of electrode and gap of electrode by photolithography. Interdigital POMSs based on different electrodes were prepared by gold sputtering on the electrode lugs. The area capacitance of the rGO/CNT-POMSs was 28.62 μF cm−2. They also had 0.004 μWh cm−2 of energy density and 1.068 μW cm−2 of power density. In addition, the charge–discharge time constant of the device was only 5.6 μs, and the charge–discharge rate was very quick. After 10,000 cycles of charge–discharge, the capacitance retention rate was still above 88%. At the ultra-high scan rate of 10000 V s−1, the devices still worked well. Compared with the POMSs based on reduced graphene oxide electrodes (rGO-POMSs) and the POMSs based on carbon nanotube electrodes (CNT-POMSs), the introduction of the CNT significantly increased the area capacitance, energy density and power density of rGO/CNT-POMSs, and significantly shortened the charge–discharge time constant. This indicated that the rGO/CNT composite electrodes had a good application prospect in the micro-chip accumulator devices.