Showing papers on "Nanotube published in 2019"
TL;DR: In this article, an asymmetric supercapacitor with the GC/MoO3-x and GC/MnO2 nanocomposites as anode and cathode, respectively, exhibits an ultrahigh energy of 150'Wh'kg−1, corresponding to an impressive volumetric energy density of 319'Wh´L−1.
235 citations
TL;DR: In this paper, a segregated network composite of carbon nanotubes with a range of lithium storage materials (for example, silicon, graphite and metal oxide particles) suppresses mechanical instabilities by toughening the composite, allowing the fabrication of high-performance electrodes with thicknesses of up to 800μm.
Abstract: Increasing the energy storage capability of lithium-ion batteries necessitates maximization of their areal capacity. This requires thick electrodes performing at near-theoretical specific capacity. However, achievable electrode thicknesses are restricted by mechanical instabilities, with high-thickness performance limited by the attainable electrode conductivity. Here we show that forming a segregated network composite of carbon nanotubes with a range of lithium storage materials (for example, silicon, graphite and metal oxide particles) suppresses mechanical instabilities by toughening the composite, allowing the fabrication of high-performance electrodes with thicknesses of up to 800 μm. Such composite electrodes display conductivities up to 1 × 104 S m−1 and low charge-transfer resistances, allowing fast charge-delivery and enabling near-theoretical specific capacities, even for thick electrodes. The combination of high thickness and specific capacity leads to areal capacities of up to 45 and 30 mAh cm−2 for anodes and cathodes, respectively. Combining optimized composite anodes and cathodes yields full cells with state-of-the-art areal capacities (29 mAh cm−2) and specific/volumetric energies (480 Wh kg−1 and 1,600 Wh l−1). While thicker battery electrodes are in high demand to maximize energy density, mechanical instability is a major hurdle in their fabrication. Here the authors report that segregated carbon nanotube networks enable thick, high-capacity electrodes for a range of materials including Si and NMC.
233 citations
TL;DR: In this paper, a hierarchical hollow framework involving interconnected highly conductive N-doped carbon nanotube networks and CoS2 particles was successfully prepared by metal-organic framework (MOF) derived method.
Abstract: The hierarchical hollow framework involving interconnected highly conductive N-doped carbon nanotube networks and CoS2 particles were successfully prepared by metal-organic framework (MOF) derived method. After the two pyrolysis process in the atmosphere of reducing gas and inert gases, numerous carbon nanotubes interlaced on the surface of framework and CoS2 nanoparticles also attached on the surface. The electromagnetic parameters of CoS2/NCNTs composites can be well controlled by regulating the loadings of sample in sample-paraffin mixture. The results demonstrate that CoS2/NCNTs with 50% loadings show superior electromagnetic wave absorption properties in the wide frequency range, almost covering the whole X bands (8–12 GHz) only with a relative thin thickness of 1.6 mm. Hierarchical hollow structure and better impedance matching performance between N-doped carbon nanocube and CoS2 nanoparticles contribute to the enhancement of microwave absorption ability. Our work confirms that hollow framework CoS2/NCNTs composites can provide a novel idea for designing high-absorbability microwave absorbers.
200 citations
TL;DR: In this paper, a bifunctional Ni Mo alloy nanotube was proposed for efficient hydrogen production coupled with anodic urea oxidation in a hybrid water electrolysis system.
199 citations
TL;DR: Recent advances in the fabrication of GDY-based nanostructures and their applications, and corresponding mechanisms, are covered, and future critical perspectives are also discussed.
Abstract: Graphdiyne (GDY), a novel one-atom-thick carbon allotrope that features assembled layers of sp- and sp2 -hybridized carbon atoms, has attracted great interest from both science and industry due to its unique and fascinating structural, physical, and chemical properties. GDY-based materials with different morphologies, such as nanowires, nanotube arrays, nanosheets, and ordered stripe arrays, have been applied in various areas such as catalysis, solar cells, energy storage, and optoelectronic devices. After an introduction to the fundamental properties of GDY, recent advances in the fabrication of GDY-based nanostructures and their applications, and corresponding mechanisms, are covered, and future critical perspectives are also discussed.
195 citations
TL;DR: A muscle type is described that provides higher performance, in which the guest that drives actuation is a sheath on a twisted or coiled core that can be an inexpensive yarn, and Theory predicts the observed performance advantages of sheath-run muscles.
Abstract: Although guest-filled carbon nanotube yarns provide record performance as torsional and tensile artificial muscles, they are expensive, and only part of the muscle effectively contributes to actuation. We describe a muscle type that provides higher performance, in which the guest that drives actuation is a sheath on a twisted or coiled core that can be an inexpensive yarn. This change from guest-filled to sheath-run artificial muscles increases the maximum work capacity by factors of 1.70 to 2.15 for tensile muscles driven electrothermally or by vapor absorption. A sheath-run electrochemical muscle generates 1.98 watts per gram of average contractile power-40 times that for human muscle and 9.0 times that of the highest power alternative electrochemical muscle. Theory predicts the observed performance advantages of sheath-run muscles.
194 citations
TL;DR: It was found that a cyanostilbene-appended glutamate compound self-assembled into helical nanotubes exhibiting both supramolecular chirality and circularly polarized luminescence (CPL) when two achiral acceptors with different energy bands were co-assembled with the nanotube.
Abstract: By constructing a supramolecular light-harvesting chiral nanotube in the aqueous phase, we demonstrate a cooperative energy and chirality transfer. It was found that a cyanostilbene-appended glutamate compound (CG) self-assembled into helical nanotubes exhibiting both supramolecular chirality and circularly polarized luminescence (CPL). When two achiral acceptors, ThT and AO, with different energy bands were co-assembled with the nanotube, the CG nanotube could transfer its chirality to both of the acceptors. The excitation energy could be transferred to ThT but only be sequentially transferred to AO. During this process, the CPL ascribed to the acceptor could be sequentially amplified. This work provides a new insight into the understanding the cooperative chirality and energy transfer in a chiral supramolecular system, which is similar to the natural light-harvesting antennas.
165 citations
TL;DR: In this paper, a graphitic carbon nitride nanotube (g-C3N4 NT) intercalated rGO nanofiltration (NF) membrane with enhanced photo-induced self-cleaning performance was presented.
162 citations
TL;DR: In this article, Fe, N and S codoped carbon matrix/carbon nanotube nanocomposites (Fe-N-S CNN) are prepared by pyrolysis of ZIF-8 impregnated with iron salt.
Abstract: MOF-derived carbon-based nanomaterials have attracted great attention due to the outstanding electrocatalytic performance, low-cost and super stability. To design an excellent catalyst, Fe, N and S codoped carbon matrix/carbon nanotube nanocomposites (Fe-N-S CNN) are prepared by pyrolysis of ZIF-8 impregnated with iron salt in this work. Benefiting from the synergistic effect of carbon matrix and nanotubes, abundant iron nitrides and thiophene-S active sites, the Fe-N-S CNN exhibits an excellent oxygen reduction reaction (ORR) performance with a half-wave potential of 0.91 V vs. RHE in alkaline conditions and 0.78 V vs. RHE in acidic conditions, while those of commercial Pt/C catalysts are 0.85 V vs. RHE and 0.795 V vs. RHE, respectively. Furthermore, Fe-N-S CNN as the cathode catalyst in a primary zinc-air battery shows a specific capacity of 700 mA h g−1.
159 citations
12 Nov 2019
TL;DR: In this article, hierarchical NiCo alloy/carbon nanorod@carbon nanotube (NiCo Alloy/Carbon Nanorod/CNT) structures were prepared by a carbonization process using NiCo-MOF-74 nanorods as precursors in Ar flow, in which the aspect ratio and the coating density of the CNTs were controlled by the ratio of Ni/Co in the precursor.
Abstract: Fabricating high-performance electromagnetic absorbents with strong absorbing intensity and wide effective absorbing bandwidth at low filler loading is still a challenge. Herein, hierarchical NiCo alloy/carbon nanorod@carbon nanotube (NiCo alloy/carbon nanorod@CNT) structures were prepared by a carbonization process using NiCo-MOF-74 nanorods as precursors in Ar flow, in which the aspect ratio of the NiCo alloy/carbon nanorod and the coating density of the CNTs could be easily controlled by the ratio of Ni/Co in the precursor. When the Ni/Co molar ratio was 1:1, a dual electric network was easily formed among the NiCo alloy/carbon nanorods as well as between the intertwined coating CNTs due to the higher aspect ratio and larger coating density, which induced significant enhancement of the comprehensive microwave absorbing properties of the NiCo alloy/carbon nanorod@CNT composites. By adding only 5 wt % to paraffin, the resulting composite displayed a maximum reflection loss of −58.8 dB and a covered an ef...
149 citations
TL;DR: This work uses a simple in situ construction method to design a heterojunction model based on molecular self-assembly, which uses a small molecule matrix for self-integration, and results in an enhanced H2 evolution rate with excellent sustainability 20.6-fold-over pure g-C3N4.
Abstract: The construction of heterojunctions provides a promising strategy to improve photocatalytic hydrogen evolution. However, how to fabricate a nanoscale TiO2/g-C3N4 heterostructure and hinder the aggregation of bulk g-C3N4 using simple methods remains a challenge. In this work, we use a simple in situ construction method to design a heterojunction model based on molecular self-assembly, which uses a small molecule matrix for self-integration, including coordination donors (AgNO3), inorganic titanium source (Ti(SO4)2) and g-C3N4 precursor (melamine). The self-assembled porous g-C3N4 nanotube can hamper carrier aggregation and it provides numerous catalytic active sites, mainly via the coordination of Ag+ ions. Meanwhile, the TiO2 NPs are easily mineralized on the nanotube template in dispersive distribution to form a heterostructure via an N-Ti bond of protonation, which contributes to shortening the interfacial carrier transport, resulting in enhanced electron-hole pairs separation. Originating from all of the above synergistic effects, the obtained Ag/TiO2/g-C3N4 heterogenous photocatalysts exhibit an enhanced H2 evolution rate with excellent sustainability 20.6-fold-over pure g-C3N4. Our report provides a feasible and simple strategy to fabricate a nanoscale heterojunction incorporating g-C3N4, and has great potential in environmental protection and water splitting.
TL;DR: In this paper, the authors presented a highly sensitive room-temperature gas sensor based on 3D titanium dioxide/graphene-carbon nanotube (3D TiO2/G-CNT) fabricated by chemical vapor deposition and sparking methods.
Abstract: This work presents a highly sensitive room-temperature gas sensor based on 3D titanium dioxide/graphene-carbon nanotube (3D TiO2/G-CNT) fabricated by chemical vapor deposition and sparking methods. Characterizations by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and Transmission electron microscopy confirmed the formation of 3D graphene-carbon nanotube nanostructures decorated with TiO2 nanoparticles. The toluene detection performances of 3D TiO2/G-CNT structures with varying Ti sparking times were investigated in comparison with 3D G-CNT, TiO2-CNT, graphene and CNTs at room temperature. From result, the optimal sparking time of 60 s led to an optimal sensor response of 42%–500 ppm at room temperature. In addition, the optimal 3D TiO2/G-CNT exhibited substantially higher toluene response, sensitivity and selectivity than 3D G-CNT, TiO2-CNT, graphene and CNTs over a low concentration range of 50–500 ppm. The toluene-sensing mechanisms of 3D titanium dioxide/graphene-carbon nanotube nanostructures were proposed based on the formation of Schottky metal-semiconductor junctions between metallic 3D graphene-carbon nanotube structures and n-type semiconducting titanium dioxide nanoparticles due to the adsorption of toluene molecules via low-temperature reducing reactions or direct charge transfer process.
TL;DR: In this paper, a mesoporous Cu-doped Co9S8 rectangular nanotube arrays (Cu-Co 9S8 NTAs) are successfully fabricated for all-solid-state asymmetric supercapacitors.
Abstract: Heteroatom doping has been regarded as an effective route to tune the electronic structure of electrode materials to achieve enhanced electrical conductivity as well as more electroactive sites and boost the devices' capacitive performance and cycling stability. Herein, novel high-performance all-solid-state asymmetric supercapacitors (ASCs) based on mesoporous Cu-doped Co9S8 rectangular nanotube arrays (Cu-Co9S8 NTAs) are successfully fabricated. Using Cu–Co(CO3)0.5(OH) nanowire arrays as the precursor and 1,3,5-benzenetricarboxylic acid (H3BTC) as the ligand, intermediate CuCo–MOF nanorod arrays are first obtained and then converted into Cu-Co9S8 rectangular NTAs via a facile sulfidation reaction. Interestingly, the intermediate CuCo–MOF nanorods play a determinant role in forming the hollow nanostructures of the final products. Due to the arrays of the unique hollow nanostructures and novel electronic properties induced by Cu doping, a battery-type electrode based on the Cu-Co9S8 NTAs exhibits a high specific capacity of 366 mA h g−1 (2636 F g−1) at 2 A g−1 and excellent cycling stability (94.0% capacity retention after 5000 cycles). Furthermore, all-solid-state ASCs assembled using the Cu-Co9S8 NTAs as the positive electrode and active carbon as the negative electrode demonstrate a high energy density of 71.93 W h kg−1 at a power density of 750 W kg−1 and outstanding cycling stability (96.2% retention after 5000 cycles). The ASC device exhibits enhanced energy density compared with reported state-of-the-art supercapacitors as well as excellent flexibility under different bending conditions.
TL;DR: In this paper, the ultra-lightweight and robust three-dimensional graphene/polydopamine modified multiwalled carbon nanotube (MWCNT-PDA) hybrid aerogels were prepared via a viable green route and applied to highly efficient heavy metal ions adsorption.
TL;DR: In this paper, a self-supported hierarchical MoS2/CoS2 nanotube array was proposed for the hydrogen evolution reaction (HER) in pH-universal electrocatalysts, where Co metal-organic frameworks (MOFs) were used as a precursor and sacrificial template to form one-dimensional CoS 2 nanotubes surrounded by vertically aligned two-dimensional MoS 2 nsheets.
Abstract: The exploitation of efficient earth-abundant electrocatalysts in a wide pH range is crucial for the practical application of the hydrogen evolution reaction (HER); but it still remains challenging. Here we demonstrate novel self-supported hierarchical MoS2/CoS2 nanotube arrays as efficient pH-universal electrocatalysts, where Co metal–organic frameworks (MOFs) are used as a precursor and sacrificial template to form one-dimensional CoS2 nanotubes surrounded by vertically aligned two-dimensional MoS2 nanosheets. Owing to the achievement of a unique hollow architecture with abundant exposed edges and accelerated reaction kinetics, the self-supported MoS2/CoS2 heterostructure exhibits a superior HER catalytic performance with long-term durability in acidic, neutral and alkaline electrolytes. Impressively, it delivers a current density of 10 mA cm−2 at low overpotentials of 90 mV in acidic media and 85 mV in alkaline media and small Tafel slope values of 30 mV dec−1 in acidic media and 34 mV dec−1 in alkaline media, respectively. Our first-principles calculations reveal that the strong interfacial interactions between MoS2 and CoS2 increase the electronic states at S–S edges and dramatically reduce the Gibbs free energy of hydrogen and the energy barrier for water dissociation. Overall, this work offers an exciting avenue for the rational design of hollow heterogeneous catalyst arrays by MOF-engaged interfacial engineering for scalable hydrogen generation.
TL;DR: In this article, the authors demonstrate an effective strategy to control the dimensionality and morphology of graphitic carbon nitride (g-C3N4) through heat treatment the precursors formed in water as a green solvent.
Abstract: Geometric dimensionality and morphology largely affect the properties and functionalities of materials; however, simultaneously regulating them to realize synergic effects is a formidable scientific and technological challenge. Here we demonstrate an effective strategy to control the dimensionality and morphology of graphitic carbon nitride (g-C3N4) through heat treatment the melamine-cyanuric acid supramolecular precursors formed in water as a “green” solvent. By varying heat treatments, the three-dimensional (3D) hexagonal prism precursors could be transformed to 3D g-C3N4 loofah-like (CNl) architectures, ultrathin two-dimensional (2D) g-C3N4 nanosheets (CNs), and ordered one-dimensional (1D) g-C3N4 nanotube (CNt) array, respectively. The adsorbed melamine molecules on the surface of precursor and atmosphere in the transformation process, play a key role in determining the morphology of products. The resulting ultrathin 2D CNs have a porous structure, a small thickness (1.6 nm), a large surface area (208.8 m2·g−1), and high conductivity, thus exhibiting higher hydrogen evolution rate (23.9 μmol h−1) by 17.3 times than the bulk g-C3N4 (CN) under visible light irradiation. This strategy results in high-quality, ultrathin CNs at yields of ∼10 wt% from raw material, much higher than those of previous reports (∼6 wt% from bulk CN). This work not only enriches our understanding of the relationship between geometric dimensionality, morphology and properties of photocatalytic nanomaterials, but also could be potentially useful for the design and growth of 1D or 2D flexible polymers for energy-related applications and beyond.
14 Aug 2019
TL;DR: Investigation of the adsorption capability of molybdenum sulfide (MoS2)/thiol-functionalized multiwalled carbon nanotube (SH-MWCNT) nanocomposite for rapid and efficient removal of heavy metals from industrial mine water found it to have a high adsorbent capacity.
Abstract: In this study, we investigate the adsorption capability of molybdenum sulfide (MoS2)/thiol-functionalized multiwalled carbon nanotube (SH-MWCNT) nanocomposite for rapid and efficient removal of hea...
TL;DR: In this article, the entropy generation of nanofluids between two stretching rotating discs under the effect of magnetohydrodynamic (MHD) and thermal radiation is examined in the presence of carbon nanotubes.
TL;DR: In this paper, a two-step analytical electrical conductivity method is adopted to calculate the effective electrical conductivities of the carbon fiber (CF)-carbon nanotube (CNT)-polymer hybrid composite.
Abstract: A two-step analytical electrical conductivity method is adopted to calculate the effective electrical conductivity of the carbon fiber (CF)-carbon nanotube (CNT)-polymer hybrid composite. First, CNTs are dispersed into the non-conducting polymer matrix and the electrical conductivity of the CNT-polymer composite is obtained. Then, CFs are randomly distributed in the CNT-polymer composite and the effective electrical conductivity of CF-CNT-polymer hybrid composite is estimated. The effect of critical parameters, including the volume fraction, alignment, agglomerated state and aspect ratio of the CNTs and the potential barrier height of the polymer on the hybrid composite electrical conductivity is evaluated. Also, the influence of the content and aspect ratio of CFs on the electric conductive behavior of the polymer hybrid composites is investigated. The results show that the polymer hybrid composite with larger aspect ratio and off alignment of CNTs presents a higher electrical conductivity.
TL;DR: In this article, a hierarchical TiO2 nanotube with uniform carbon coatings is synthesized as the full solar spectrum photocatalytic materials for O2 evolution by a facile solvothermal method.
Abstract: Smart architectures of TiO2 are attracting increasing attention due to their outstanding properties in a broad range of fields. Herein, hierarchical TiO2 nanotube with uniform carbon coatings is synthesized as the full solar spectrum photocatalytic materials for O2 evolution by a facile solvothermal method. This unique structure consists of an interstitial hollow spaces and a functional nanotube shell assembled from two-dimensional (2D) nanosheets. By adjusting the types of solvents and reaction time, the morphologies of TiO2/C composites can be tuned to nanoparticles, nanorods, or hierarchical nanotubes. Among these morphologies, the TiO2/C hierarchical nanotube exhibits the best photocatalytic activity and favorable stability toward oxygen evolution from water oxidation under full solar spectrum light irradiation. The reason is attributed to the desirable incorporation of visible/near-infrared (NIR) light active carbon coating with UV light responsive TiO2 for promoted solar energy utilization. Besides, the solvothermal step leads to hierarchical nanotube structures which can generate multiple reflections of incident light so as to promote an efficient light harvesting due to an enhanced specific surface area (244.4 m2 g−1) and light scattering ability. Moreover, the generated carbon coatings on the surface of TiO2 facilitate electron-hole separation.
TL;DR: A smart design of ordered nanotube arrays of iron oxide (Fe2 O3 ) is presented as efficient sodium anode, simply enabled by surface sulfurization, which may open a new door in engineering efficient anode based on earth-abundant materials.
Abstract: High-power sodium-ion batteries capable of charging and discharging rapidly and durably are eagerly demanded to replace current lithium-ion batteries. However, poor activity and instable cycling of common sodium anode materials represent a huge barrier for practical deployment. A smart design of ordered nanotube arrays of iron oxide (Fe2 O3 ) is presented as efficient sodium anode, simply enabled by surface sulfurization. The resulted heterostructure of oxide and sulfide spontaneously develops a built-in electric field, which reduces the activation energy and accelerates charge transport significantly. Benefiting from the synergy of ordered architecture and built-in electric field, such arrays exhibit a large reversible capacity, a superior rate capability, and a high retention of 91% up to 200 cycles at a high rate of 5 A g-1 , outperforming most reported iron oxide electrodes. Furthermore, full cells based on the Fe2 O3 array anode and the Na0.67 (Mn0.67 Ni0.23 Mg0.1 )O2 cathode deliver a specific energy of 142 Wh kg-1 at a power density of 330 W kg-1 (based on both active electrodes), demonstrating a great potential in practical application. This material design may open a new door in engineering efficient anode based on earth-abundant materials.
TL;DR: In this paper, the authors review the mechanical properties of two phase and three phase composites, fabricated by incorporating graphene and carbon nanotube (CNT) nanofillers in epoxy resin individually followed by studying the synergetic effect of hybrid nano-fills in the epoxy resins.
Abstract: Carbon based nanofillers (graphene and carbone nanotube) are widely used as reinforcing agents with epoxy based nanocomposites. The aim of paper is to review mechanical properties of two phase and three phase composites, fabricated by incorporating graphene and carbon nanotube (CNT) nanofillers in epoxy resin individually followed by studying the synergetic effect of hybrid nanofillers in the epoxy resin. Discussion on verification of results by various characterization techniques such as SEM, TEM, XRD, and FTIR is done to understand the influence of filler materials on interfacial properties of composites along with presenting various diversified applications of epoxy based composites.
TL;DR: In this paper, the synthesis of carbon@Na4Ti9O20 (C@NTO) core-shell nanotube as novel electrodes for hybrid capacitive deionization (HCDI) with enhanced performance to overcome the several key issues of desalination.
01 Nov 2019
TL;DR: In this article, the potential of carbon nanotube digital electronics is explored, examining the development of carbon-nanotube-based field effect transistors and integrated circuits, and the challenges that exist in delivering large-scale systems.
Abstract: It is anticipated that the scaling of silicon complementary metal–oxide–semiconductor (CMOS) devices will end around 2020, but alternative technologies capable of maintaining advances in computing power and energy efficiency have not yet been established. Among various options, carbon-nanotube-based electronics has been shown to be one of the most promising candidates. A range of methods have been developed to prepare high-purity semiconducting carbon nanotubes suitable for use in integrated circuits, and 5 nm nanotube transistors with superior performance to that of silicon CMOS have been demonstrated. Here, we explore the potential of carbon nanotube digital electronics. We examine the development of nanotube-based CMOS field-effect transistors and the different nanotube material systems available to build integrated circuits. We also highlight the medium-scale integrated circuits created to date and consider the challenges that exist in delivering large-scale systems. This Perspective explores the potential of carbon nanotube electronics, examining the development of nanotube-based field-effect transistors and integrated circuits, and the challenges that exist in delivering large-scale systems.
TL;DR: A two-ply symmetric yarn supercapacitor assembled from the NiCo2S4/Ni-Co layered double hydroxide/Au/cotton yarn electrode reaches an areal energy density of 3.5 μWh cm-2 and has excellent electrochemical properties including high capacitance, excellent rate performance and stable cycling performance.
Abstract: Constructing high capacitance active materials and three-dimensional (3D) conductive networks inside textile yarn frames is a promising strategy to synthesize yarn supercapacitor electrodes. In this study, growing NiCo2S4@Ni-Co layered double hydroxide (LDH) nanotube arrays on Au-metalized cotton yarns yields a novel yarn supercapacitor electrode material. The resulting yarn electrode possesses numerous merits, including high electrical conductivity from NiCo2S4 and Au-metalized cotton yarns, high capacitance of Ni-Co LDH nanosheets, and the 3D hierarchical electrode structure. The unique electrode structure leads to excellent electrochemical properties including high capacitance (5680 mF cm-2), excellent rate performance, and stable cycling performance. A two-ply symmetric yarn supercapacitor assembled from the NiCo2S4/Ni-Co LDH/Au/cotton yarn electrode reaches an areal energy density of 3.5 μW h cm-2.
TL;DR: Results confirmed that CuFe2O4 with tetragonal structure, uniform distribution, and less agglomeration was located at HNTs, which led to use it as a heterogeneous catalyst in the synthesis of pyrazolopyridine derivatives.
Abstract: In this study, mesoporous halloysite nanotubes (HNTs) were modified by CuFe2O4 nanoparticles for the first time. The morphology, porosity and chemistry of the CuFe2O4@HNTs nanocomposite were fully characterized by Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM) image, transmission electron microscope (TEM) images, energy-dispersive X-ray (EDX), X-ray diffraction (XRD) pattern, Brunauer-Emmett-Teller (BET) adsorption-desorption isotherm, thermogravimetric (TG) and vibrating sample magnetometer (VSM) curve analyses. The results confirmed that CuFe2O4 with tetragonal structure, uniform distribution, and less agglomeration was located at HNTs. CuFe2O4@HNTs nanocomposite special features were high thermal stability, crystalline structure, and respectable magnetic property. SEM and TEM results showed the nanotube structure and confirmed the stability of basic tube in the synthetic process. Also, inner diameters of tubes were increased in calcination temperature at 500 °C. A good magnetic property of CuFe2O4@HNTs led to use it as a heterogeneous catalyst in the synthesis of pyrazolopyridine derivatives. High efficiency, green media, mild reaction conditions and easily recovery of the nanocatalyst are some advantages of this protocol.
TL;DR: In this article, anodization process followed by the chemical bath deposition technique has been used to prepare the samples in this work and the best photoelectrochemical activity and cathodic protection were shown by the iron-cobalt WTiO2 nanotube (WTNTs) films deposited on titanium substrate.
TL;DR: A self-assembly of clay nanotubes in functional arrays for the production of organized organic/inorganic heterostructures is described, and core-shell mesocatalysts are based on a safe and cheap natural clay nanomaterial and may be scaled up for industrial applications.
Abstract: A self-assembly of clay nanotubes in functional arrays for the production of organized organic/inorganic heterostructures is described. These 50-nm-diameter natural alumosilicate nanotubes are biocompatible. Halloysite allows for 10-20 wt % chemical/drug loading into the inner lumen, and it gives an extended release for days and months (anticorrosion, self-healing, flame-retardant, antifouling, and antibacterial composites). The structured surfaces of the oriented nanotube micropatterns enhance interactions with biological cells, improving their capture and inducing differentiation in stem cells. An encapsulation of the cells with halloysite enables control of their growth and proliferation. This approach was also developed for spill petroleum bioremediation as a synergistic process with Pickering oil emulsification. We produced 2-5-nm-diameter particles (Au, Ag, Pt, Co, Ru, Cu-Ni, Fe3O4, ZrO2, and CdS) selectively inside or outside the aluminosilicate clay nanotubes. The catalytic hydrogenation of benzene and phenol, hydrogen production, impacts of the metal core-shell architecture, the metal particle size, and the seeding density were optimized for high-efficiency processes, exceeding the competitive industrial formulations. These core-shell mesocatalysts are based on a safe and cheap natural clay nanomaterial and may be scaled up for industrial applications.
TL;DR: In this paper, a carbon layer coated NiCo2S4 hollow nanotubes were prepared by simple solvothermal method using polyacrylonitrite (PAN) as template, which not only maximized the catalytic active sites but also protected from electrolyte corrosion to improve the activity and stability.
TL;DR: In this article, a Fe/N/S-doped porous carbon nanotube catalyst was synthesized by a one-pot method using FeCl3 as the flocculant, oxidant, dopant and activating agent.
Abstract: Exploring simple and flexible methods to synthesize oxygen reduction reaction (ORR) catalysts with high catalytic activity is of great significance for the large-scale application of fuel cells. Here we report a Fe/N/S-doped porous carbon nanotube catalyst which was simply synthesized by a one-pot method using FeCl3 as the flocculant, oxidant, dopant and activating agent, which makes full use of the multi-functional roles of Fe species. The results show that the specific surface area of the carbon nanotubes obtained by iron species activation is nearly four times that of the un-activated, and micro/mesoporous structures have been largely developed. Moreover, the Fe/N/S-doped porous carbon nanotube catalyst exhibits efficient ORR catalytic activity, long-term stability, and high endurance to methanol in both alkaline and acidic media. This ingenious synthesis strategy for preparing an efficient ORR catalyst by making full use of the versatility of the Fe species provides a new insight into the synthesis and application of carbon materials.