Introduction Of Carbon Nanotubes Research Articles

From carbon nanotubes to ultra-sensitive, extremely-stretchable and self-healable hydrogels

Bearing several merits including resemblance to tissues, tunable conductivity, and mechanical flexibility, conductive hydrogels have been widely applied in wearable sensors, implantable bioelectronics, artificial skins, etc. However, the fragile nature, lack of self-healing capability, and insufficient sensitivities at low strains of traditional conductive hydrogels cannot meet the increasing demands of flexible electronics. Here, carbon nanotubes (CNTs) were dispersed in water with the assistance of bis benzyl-modified polyethylene glycol (B-PEG181), which served as additional cross-linkers to prepare hydrogel by introducing acrylamide (AM) and N,N’-methylene bisacrylamide (MBAA). The synergy of physical entanglements and π-π interactions led to extreme stretchability (0∼132 mm/mm) and self-healable capability. In addition, the introduction of CNTs and lithium chloride endowed the hydrogel with ultra-high sensitivity (GF = 122.7, at 6.0∼8.0 mm/mm strain), superior to present sensors. Consequently, the obtained sensor could detect various human motions. It is envisioned that the remarkable performances empower the obtained gel promising applications in strain sensors, human-machine interfaces, and soft robots.

MgO-incorporated carbon nanotubes-reinforced Mg-based composites to improve mechanical, corrosion, and biological properties targeting biomedical applications

In this study, magnesium oxide (MgO) nanoparticles are incorporated on carbon nanotubes (CNTs) to reinforce Mg–3Zn–1Mn alloy (ZM31 alloy) by semi-powder metallurgy, followed by hot extrusion, with the purpose of improving the mechanical and biological properties of Mg-based alloy. The microstructural analysis of the nanocomposites indicated a reduction in grain size of Mg alloy with the incorporation of CNTs with a maximum reduction of 61% (ZM31/CNTs), with further reduction in grain size (68%) detected when MgO integrated CNTs composites (ZM31/MgO-CNTs). The compression characteristics of the composites indicate an increase in ultimate compressive strength of 36% and 44%, respectively, with the incorporation of CNTs and MgO-CNTs fillers, and the hardness of Mg alloy increases by 37% and 58%, respectively, with the incorporation of CNTs and MgO-CNTs fillers. The strengthening mechanisms of Mg alloy composites reinforced with MgO-CNTs were discussed. Furthermore, MgO bounded CNTs fillers decelerated the degradation rate of Mg-based alloys, whereas the introduction of CNTs to Mg alloy had a less significant effect. Besides, the ZM31/MgO-CNTs composite indicated superior cytocompatibility because of its lower corrosion rates. According to the overall results, the outstanding mechanical performance, appropriate corrosion characteristics, and good cytocompatibility of the ZM31/MgO-CNTs composites verified their potential in medical fields.

Manganese-based metal-organic-framework derived hydrophilic cathode with carbon nanotubes introduced for long-life and high-performance aqueous zinc-ion battery

Aqueous zinc-ion batteries (ZIBs) have received widespread attention due to their high specific capacity (820 mA h g−1), high safety and low cost. Manganese (Mn)-based oxides show great potential as cathode materials for aqueous ZIBs, but they also face problems of low conductivity and poor rate performance. The introduction of carbon nanotubes (CNTs) can improve the hydrophilicity, enhance the conductivity of Mn-based oxides, and further improve the cycling performances of the ZIBs at high current density. Therefore, in this paper, Mn-based metal-organic-framework (Mn-MOF) is chosen as a template, while carboxylic CNTs are introduced during the synthesis process of Mn-MOF, finally after further calcination, composite material of Mn-based oxides, MOF-derived carbon and CNTs (MnOx@[email protected]) is prepared as the cathode for aqueous ZIBs. After 5000 cycles at a current density of 3 A g−1, the capacity retains 96.7 mA h g−1, while the capacity decay rate is 2% only. This work provides a solution to the challenges of Mn-based oxides for aqueous ZIBs cathode, thus achieve better electrochemical performances.

Ultraflexible, Breathable, and Form-Stable Phase Change Fibrous Membranes by Green Electrospinning for Personal Thermal Management

Advanced textiles for personal thermal management (PTM) are more precise and energy-saving than traditional heating/cooling strategies. Applying phase change materials (PCMs) in PTM is sustainable and effective but challenging due to the intrinsic rigid character of PCMs and the leakage issue in phase transition. In this work, we employed poly(ethylene glycol) (PEG) as a functional material and poly(vinyl alcohol) (PVA) as a polymer skeleton by green electrospinning to endow the composite membranes with superior flexibility, breathability, and thermal regulation capability. The introduction of carbon nanotubes (CNTs) promoted the mechanical properties and thermal conductivity of the prepared membranes. The thermal conductivity of resultant membranes was enhanced by 40.4% with only 1.5% weight content of CNTs. Furthermore, surface chemical cross-linking was applied to improve water-resistance properties and minimize the confinement on the PEG segment. The prepared membranes have a reasonable temperature range (∼26.9–38.9 °C) in the phase change process with a melting latent heat of 60.1 J/g and freezing latent heat of 59.1 J/g as the mass ratio of PEG reached 55 wt %. These flexible fibrous membranes with optimal energy storage capacity and eco-friendly characteristics indicate they will be a promising candidate for personal thermal management.

Poly(Anthraquinonyl Sulfide)/CNT Composites as High-Rate-Performance Cathodes for Nonaqueous Rechargeable Calcium-Ion Batteries.

Calcium‐ion batteries (CIBs) are considered as promising alternatives in large‐scale energy storage due to their divalent electron redox properties, low cost, and high volumetric/gravimetric capacity. However, the high charge density of Ca2+ contributes to strong electrostatic interaction between divalent Ca2+ and hosting lattice, leading to sluggish kinetics and poor rate performance. Here, in situ formed poly(anthraquinonyl sulfide) (PAQS)@CNT composite is reported as nonaqueous calcium‐ion battery cathode. The enolization redox chemistry of organics has fast redox kinetics, and the introduction of carbon nanotube (CNT) accelerates electron transportation, which contributes to fast ionic diffusion. As the conductivity of the PAQS is enhanced by the increasing content of CNT, the voltage gap is significantly reduced. The PAQS@CNT electrode exhibits specific capacity (116 mAh g−1 at 0.05 A g−1), high rate capacity (60 mAh g−1 at 4 A g−1), and an initial capacity of 82 mAh g−1 at 1 A g−1 (83% capacity retention after 500 cycles). The electrochemical mechanism is proved to be that the PAQS undergoes reduction reaction of their carbonyl bond during discharge and becomes coordinated by Ca2+ and Ca(TFSI)+ species. Computational simulation also suggests that the construction of Ca2+ and Ca(TFSI)+ co‐intercalation in the PAQS is the most reasonable pathway.

Hybrid sintering of CNT/PZT ceramics using microwave oven

Piezoelectric materials play a major role in a variety of applications such as sensing, actuation and energy harvesting. Lead Zirconate Titanate (PZT) is a commonly used piezoelectric material because of its superior piezoelectric properties. One of the key elements to optimize the manufacturing process of this group of piezoelectric materials is minimizing the processing time and energy required to prepare ceramic parts. Among the production steps, the sintering process needs the most time and consumes the most energy. In this study, a rapid sintering method of bulk PZT elements is proposed based on microwaves. Carbon nanotubes (CNTs) are added to the material as an absorption aid. The effects of different sintering temperatures, microwave (MW) power and CNT weight fraction on the grain size, physical, mechanical and piezoelectric properties are investigated. The results show that higher MW powers lead to smaller grain sizes, higher mechanical properties but lower densities and electromechanical properties. The introduction of CNTs to the PZT material results in higher heating rates at the initial portion of the sintering process as well as smaller and more uniform grains while decreasing the density. The ceramic parts with 1 wt% CNTs concentration have the highest piezoelectric coefficient after sintering and poling. Generally, the proposed method is more environmentally friendly than the conventional method because not only does it require a lower processing time and energy, but also it leads to the formation of a single-phase perovskite structure without the need for additional amounts of lead.

CNTs decorated Cu-BTC with catalytic effect for high-stability lithium-sulfur batteries

Lithium-sulfur (Li–S) batteries have received widespread attention for the reason that their specific capacity is dramatically higher than that of current lithium-ion batteries. However, Li–S batteries still have problems such as poor conductivity, severe “shuttle effect”, huge volume changes in the cathode, and lithium dendrites. Here, we report the introduction of carbon nanotubes (CNTs) into metal-organic frameworks (MOFs)-Cu-BTC and obtained Cu-BTC/CNTs with a three-dimensional structure by hydrothermal method. This structure solves the problem of inefficient electrochemical performance caused by poor conductivity when using Cu-BTC to adsorb lithium polysulfides (LiPSs). At the same time, the abundant porous structure is capable of effectively alleviating the volume expansion of the cathode during the reaction process. More importantly, Cu-BTC/CNTs catalyzes redox reactions, greatly improves the catalytic effect of Cu-BTC on LiPSs and the utilization of sulfur. As a result, The Cu-BTC/CNTs/S as sulfur host in the Li–S batteries cathode delivers an initial discharge of 924.69 mAh/g at 0.2C. Even at a high rate of 1C, it also exhibits a specific capacity of 805.28 mAh/g and still maintains 406.68mAh/g after 200 cycles at 1C. The above results indicate that the introduction of CNTs not only improves the overall conductivity of the material but also can fully exert the catalytic effect of Cu-BTC on the conversion of LiPSs. This work provides a convenient strategy to promote the conversion of LiPSs along with improving the catalytic activity of MOFs in Li–S batteries.

Revealing the intrinsic effects of introduced carbon nanotubes for Bi2O3 energy storage materials

A lot of works have revealed that the introduction of Carbon nanotubes (CNTs) into oxide-based electrode materials is an efficient strategy to improve their energy storage performance. In this work, we firstly demonstrated the intrinsic effects of introduced CNTs for bismuth oxide (Bi2O3) electrode materials, including the physical, chemical and energy storage performance. Our results revealed that the optimal value of introduced CNTs into Bi2O3 is 1.5% (in weight ratio), which demonstrated a specific capacitance of 1012 C g−1 at 1 A g−1, about 1.52 times higher than the pristine Bi2O3. The obtained optimal energy storage performance by introduced CNTs can be explained by; 1) the introduced CNTs were helpful to reduce the average particle size of Bi2O3 powder, here the particle size was greatly reduced from 363 nm to 112 nm; 2) the small Bi2O3 particle with the introduced CNTs demonstrated more than 1.97 times enhancement of specific surface area; 3) the total conductivity of the obtained composite electrode was greatly enhanced by 320.31 times and, 4) however, due to the lower theoretical capacity of CNTs, the total specific capacitance of composite electrode showed a significant reduction by introducing excess CNTs. We believe that this work provides a strong support to guide the introduction of CNTs into Bi2O3-based energy storage materials for optimizing electrochemical performance.

Recent Applications of Carbon Nanotubes in Organic Solar Cells.

In recent years, carbon-based materials, particularly carbon nanotubes (CNTs), have gained intensive research attention in the fabrication of organic solar cells (OSCs) due to their outstanding physicochemical properties, low-cost, environmental friendliness and the natural abundance of carbon. In this regard, the low sheet resistance and high optical transmittance of CNTs enables their application as alternative anodes to the widely used indium tin oxide (ITO), which is toxic, expensive and scarce. Also, the synergy between the large specific surface area and high electrical conductivity of CNTs provides both large donor-acceptor interfaces and conductive interpenetrating networks for exciton dissociation and charge carrier transport. Furthermore, the facile tunability of the energy levels of CNTs provides proper energy level alignment between the active layer and electrodes for effective extraction and transportation of charge carriers. In addition, the hydrophobic nature and high thermal conductivity of CNTs enables them to form protective layers that improve the moisture and thermal stability of OSCs, thereby prolonging the devices’ lifetime. Recently, the introduction of CNTs into OSCs produced a substantial increase in efficiency from ∼0.68 to above 14.00%. Thus, further optimization of the optoelectronic properties of CNTs can conceivably help OSCs to compete with silicon solar cells that have been commercialized. Therefore, this study presents the recent breakthroughs in efficiency and stability of OSCs, achieved mainly over 2018–2021 by incorporating CNTs into electrodes, active layers and charge transport layers. The challenges, advantages and recommendations for the fabrication of low-cost, highly efficient and sustainable next-generation OSCs are also discussed, to open up avenues for commercialization.

Stretchable, self-healing and adhesive sodium alginate-based composite hydrogels as wearable strain sensors for expansion-contraction motion monitoring.

Developing multifunctional hydrogels with stretchability, self-healing ability, adhesiveness, and conductivity into flexible strain sensors for human motion and health monitoring has attracted great attention and is highly desired. However, the present motion detectors mainly focus on stretching, bending, and twisting of different body parts while the expansion-contraction motion has been rarely investigated. In this study, along with carbon nanotubes (CNTs) as conductive components, sodium alginate (Alg) modified with 3-aminophenylboronic acid (PBA) and dopamine (DA) were synthesized and employed as precursors to prepare a multifunctional Alg-CNT hydrogel. The formed dynamic covalent bonds between PBA and DA endowed the hydrogel with a rapid self-healing property (30 s) while the introduction of CNTs remarkably enhanced the mechanical strength and electrical conductivity of the hydrogel. Moreover, the as-prepared hydrogel displayed a satisfactory stretchability (500%) and self-adhesiveness to various substrates. When used as a strain sensor, the Alg-CNT hydrogel that exhibited a fast response (150 ms) and ultra-durability (over 30 000 cycles) was demonstrated to be capable of monitoring subtle expansion-contraction motions (e.g., human breathing and mouse heart beating) via periodic and repeatable electrical signals. Therefore, this multifunctional hydrogel is highly suitable for monitoring expansion-contraction motions, indicating its potential applications in personal health monitoring.

О влиянии углеродных нанотрубок на физико-механические свойства полипропилена

One of the most interesting and promising materials of our time is carbon nanotubes. Most applications of nanotubes are associated with the possibility of combining them with other materials in the form of alloys, mixtures, composites or hybrid materials. In particular, the idea of including carbon nanotubes as a filler in various polymer-based matrices (for example, traditional polymers such as thermoplastics, thermosetting materials or elastomers, as well as conjugated polymers) for the formation of polymer/carbon nanotube nanocomposites has revolutionized materials science and engineering. The introduction of carbon nanotubes into the composite structure affects the structure and properties of the polymer binder, as well as the composite material as a whole. Currently, there are no experimental developments on the basis of which the introduction, distribution and stabilization of the dispersion of carbon nanotubes in polymer composites would be implemented in industrial technology. The development of the most effective methods for introducing carbon nanotubes into polymer materials and determining their effect on the physical and mechanical properties of polymers is an urgent and priority task. It is possible that these methods will be able to find application in the industrial production of polymer composite materials intended for use and operation in various extreme conditions (whether it is high temperatures, erosion, high force exposure or highly acidic/highly alkaline environments). The main physical and mechanical properties of polypropylene samples saturated with carbon nanotubes taken at different concentrations (0; 0.01; 0.05 and 0.1 wt. %), who found that the addition of CNT in large quantities negatively affects the tensile and bending strength limits, which may be associated with an increase in the degree of heterogeneity of the structure and the appearance of large agglomerates, which will be points of stress concentration. With an increase in the mass fraction of carbon nanotubes in the polymer nanocomposite, the tangent of the dielectric loss angle increases, which leads to better conductivity of the sample containing a larger number of nanotubes. This may be due to the fact that nanotubes become conductors of electric current in the volume of the polymer matrix.

Low cost, eco-friendly, modified fly ash-based shape-stabilized phase change material with enhanced thermal storage capacity and heat transfer efficiency for thermal energy storage

Owing to the high thermal capacity and nearly constant temperature during phase change, phase change material has been considered one of the most promising solar thermal energy storage materials. However, the development of high-performance shape-stabilized phase change material (SSPCM) based on a low-cost and eco-friendly supporting material remains a big challenge. Herein, a systematic experimental framework is proposed and used to respond to the challenge. By applying this framework, acid-modified fly ash (AMFA) was firstly used as the supporting material for lauric acid (LA) to prevent its leakage, while carbon nanotubes (CNTs) were utilized to improve its thermal conductivity. Specifically, the LA/AMFA/CNTs composites were synthesized via a facile and low-cost direct impregnation method. Subsequently, the as-prepared composites were systematically investigated by various characterization techniques. The results of leakage tests exhibited that the acid treatment could improve the PCM loading of fly ash and the relevant mechanism of acid-modified fly ash was identified. With the introduction of CNTs, the heat transfer efficiency of LA/AMFA/CNTs had been enhanced substantially. More importantly, compared with conventional supporting materials, the used fly ash in this work revealed much better environmental sustainability which we believe is of vital importance for the large-scale application of SSPCMs. Therefore, the study results not only facilitate the development of the desirable SSPCM based on cheap and eco-friendly supporting material and promote its practical application, but also serve to improve the comprehensive utilization level of fly ash solid waste. • Acid modification of fly ash was carried out to improve the latent heat of the SSPCM. • Mechanism of the latent heat enhancement was in-depth analyzed. • Heat transfer enhancement mechanism of the SSPCM was provided. • Sustainable assessment of the prepared SSPCM was performed.

Molecular dynamics study on the reinforcing effect of incorporation of graphene/carbon nanotubes on the mechanical properties of swelling rubber

Molecular models of the swollen nitrile rubber (NBR) matrix reinforced by the same weight percentage of the carbon nanotubes (CNT) and graphene (GN) were developed. The tensile and shear behaviors of the composites in swollen state were mainly studied via molecular dynamics simulations. The simulation results showed that the introduction of CNT and GN significantly improved the mechanical properties of the swollen NBR matrix. Higher elastic modulus, tensile strength and shear modulus of the composites were obtained by the incorporation of GN as reinforcement than that of CNT. With the increase in CNT/GN content, the elastic modulus, tensile strength and shear modulus of the swollen NBR matrix were further improved. It was also observed that CNT/GN prevented the diffusion of the cyclohexane and delayed the swelling of the NBR matrix, and GN performed better. To explore the mechanisms on the above phenomenon, the atom displacements, interaction energy between the nano-reinforcements and rubber matrices, MSD of the cyclohexane and the free volume of the polymer composites were examined and interpreted accordingly.

Determination of the effect of carbon nanotubes on the microstructure and functional properties of polycarbonate-based polymer nanocomposite materials

Polymer nanocomposites are widely used in various high-tech industries. Due to the combination of the elasticity of the matrix and the strength of the inorganic filler, they have improved functional characteristics compared to unfilled polymers. The article is devoted to determining the effect of carbon nanotubes (CNT) on the microstructure and properties of polymeric nanocomposite materials for 3D printing based on polycarbonate. As a result of this work, a series of composite materials was manufactured using a piston extruder. Their microstructure and functional characteristics were investigated using methods of optical microscopy, thermophysical, electrical and mechanical analysis. It was found that CNTs form clusters in the polymer matrix, which form a percolation network at a content of 0.5–0.8 %. This feature of the structure formation of CNTs provided an abrupt increase in the functional characteristics of the materials obtained. It is shown that with an increase in the filler content in the system to 3 %, the thermal conductivity rapidly increases to 1.22 W/(m∙K). A similar effect is observed for the electrical conductivity, which increases by seven orders of magnitude from 10-12 to 10-5 S/cm at 3 % CNT content in the system, exhibiting percolation behavior. With the introduction of CNTs, the crystallinity degree of the polymer matrix decreases by almost 15 %, due to the fact that the developed surface of the nanotubes creates steric hindrances for polycarbonate macromolecules. This effect almost negates the reinforcing effect of nanotubes; therefore, the mechanical tensile strength with the introduction of 3 % CNTs increases by only 21 % compared to the unfilled matrix. In terms of their functional characteristics, the obtained materials are promising for the creation of filaments for 3D printing on their basis.

Highly Sensitive, Flexible, Stable, and Hydrophobic Biofoam Based on Wheat Flour for Multifunctional Sensor and Adjustable EMI Shielding Applications.

Biofoam materials are attractive alternatives for petroleum-based foams to be used to solve environmental problems. Inspired by steamed bread, we report herein a novel utilization of wheat flour (WF) with the introduction of carbon nanotubes (CNTs) to form an environmentally friendly WF/CNT composite foam. This foam displayed a high elasticity (nearly 100% shape recovery), recyclable (5000 cycles), fast (100 ms), and superstability pressure-sensing response. It could serve as a new pressure sensor to detect the tiny pressure (1.76 Pa) and acoustic vibrations from piano notes. As an acoustic sensor, WF/CNT foam detected and recognized different volumes and frequencies of piano sounds. As an electromagnetic interference (EMI) shielding switch, the EMI shielding effectiveness (SE) of the foam could be easily regulated under self-fixable compression-recovery cycles. In addition, the WF/CNT foam could be converted into the WF/CNT film by a hot-compress process. This flexible film was applied as a multifunctional sensing device for detecting various motions. Therefore, wheat flour as a renewable resource could be designed into various WF-based biofoams with new functionalities and outstanding mechanical properties through a simple process.

Boosting Hydrogen Evolution on MoS2/CNT Modified by Poly(sodium‐p–styrene sulfonate) via Proton Concentration in Acid Solution

AbstractEngineering the surface and the electronic structure of electrocatalysts is a typical and effective strategy to enhance their catalytic performance. Herein, MoS2 grown on carbon nanotubes (MoS2/CNT) were synthesized through a hydrothermal process, then certain polyelectrolytes were absorbed onto the surface, including poly(sodium‐p‐styrenesulfonate) (PSS), polyacrylic acid (PAA), sodium polyacrylate (PAAS) and polyethyleneimine (PEI). The negatively charged groups of PSS could enrich the surrounding H+ in the acid electrolyte via electrostatic interaction, which greatly improved the catalytic performance of PSS‐MoS2/CNT. Moreover, the introduction of carbon nanotubes not only improved the conductivity of the electrocatalyst, but also prevented the agglomeration of MoS2 nanosheets. Therefore, PSS‐MoS2/CNT displayed the best hydrogen evolution reaction (HER) performance in 0.5 M H2SO4 solution. It only required 114 mV to obtain the current density of 10 mA ⋅ cm−2 with a small Tafel slope of 46.05 mV ⋅ dec−1. Different polyelectrolytes were also used to modify MoS2/CNT to verify the factors to affect the HER performance of MoS2/CNT. This strategy provides a practicable direction of the synthesis of efficient, low‐cost and environmentally‐friendly electrocatalysts for HER.

Investigation on the Strengthening Mechanisms of Nickel Matrix Nanocomposites.

The strengthening effect of carbon nanotubes (CNTs) in metal matrix nanocomposites occurs due to several mechanisms that act simultaneously. The possible strengthening mechanisms for metal matrix nanocomposites reinforced with CNTs consist of: (1) load transfer, (2) grain refinement and texture strengthening, (3) second phase strengthening, and (4) strain hardening. The main focus of this work is to identify the strengthening mechanisms that play a role in the case of the Ni-CNT nanocomposite produced by powder metallurgy. For the dispersion and mixing of the metallic powders with CNTs, two different routes were performed by ultrasonication and ball milling. The results indicated that four different strengthening mechanisms are present in the nanocomposites and had a different contribution to the final mechanical properties. The load transfer and the increase in dislocation density seem to strongly affect the properties and microstructure of the nanocomposite. The grain refinement and the presence of second phase particles have a small contribution in the strengthening of this nanocomposite, since the introduction of CNTs in the Ni matrix slightly affects the size and orientation of the grains in the matrix and a few nanometric particles of Ni3C were identified.

Carbon Nanotubes and Polydopamine Modified Poly(dimethylsiloxane) Sponges for Efficient Oil-Water Separation.

In this paper, effective separation of oil from both immiscible oil–water mixtures and oil-in-water (O/W) emulsions are achieved by using poly(dimethylsiloxane)-based (PDMS-based) composite sponges. A modified hard template method using citric acid monohydrate as the hard template and dissolving it in ethanol is proposed to prepare PDMS sponge composited with carbon nanotubes (CNTs) both in the matrix and the surface. The introduction of CNTs endows the composite sponge with enhanced comprehensive properties including hydrophobicity, absorption capacity, and mechanical strength than the pure PDMS. We demonstrate the successful application of CNT-PDMS composite in efficient removal of oil from immiscible oil–water mixtures within not only a bath absorption, but also continuous separation for both static and turbulent flow conditions. This notable characteristic of the CNT-PDMS sponge enables it as a potential candidate for large-scale industrial oil–water separation. Furthermore, a polydopamine (PDA) modified CNT-PDMS is developed here, which firstly realizes the separation of O/W emulsion without continuous squeezing of the sponge. The combined superhydrophilic and superoleophilic property of PDA/CNT-PDMS is assumed to be critical in the spontaneously demulsification process.

Fe-doped Ni0.85Se nanospheres interspersed into carbon nanotubes as efficient and stable electrocatalyst for overall water splitting

Developing and preparation of stable and efficient non-noble metal electrocatalysts is vital for overall water splitting. Herein, a series of Fe-doped Ni0.85Se (FexNi0.85-xSe, x = 0.02, 0.04, 0.05, 0.06, 0.08, 0.1, 0.15, 0.2, 0.3 and 0.4) catalysts are synthesized successfully by one-step hydrothermal method and studied as high active bifunctional catalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in electrolysis water splitting. The results indicates that a suitable doping can make different metal ions have a synergistic effect and improve catalytic performance. The optimal Fe0.08Ni0.77Se sample shows excellent OER and HER activities. Subsequently, the introduction of carbon nanotubes (CNTs) forming Fe0.08Ni0.77Se/CNT composite further enhances the electrocatalytic activity due to high electric conductivity of carbon nanotubes network. The resulted Fe0.08Ni0.77Se/CNT3 composite exhibits smaller overpotential of 204 mV and 108 mV at a current density of 10 mA cm−2 and a low Tafel slope of 58 mV dec−1 and 59 mV dec−1 than that of other composites for OER and HER, respectively. The results demonstrate that Fe0.08Ni0.77Se/CNT3 is an excellent bifunctional catalyst, providing a promising candidate for electrocatalytic water splitting.

Vanadium Pentoxide Nanofibers/Carbon Nanotubes Hybrid Film for High-Performance Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries (ZIBs) with the characteristics of low production costs and good safety have been regarded as ideal candidates for large-scale energy storage applications. However, the nonconductive and non-redox active polymer used as the binder in the traditional preparation of electrodes hinders the exposure of active sites and limits the diffusion of ions, compromising the energy density of the electrode in ZIBs. Herein, we fabricated vanadium pentoxide nanofibers/carbon nanotubes (V2O5/CNTs) hybrid films as binder-free cathodes for ZIBs. High ionic conductivity and electronic conductivity were enabled in the V2O5/CNTs film due to the porous structure of the film and the introduction of carbon nanotubes with high electronic conductivity. As a result, the batteries based on the V2O5/CNTs film exhibited a higher capacity of 390 mAh g−1 at 1 A g−1, as compared to batteries based on V2O5 (263 mAh g−1). Even at 5 A g−1, the battery based on the V2O5/CNTs film maintained a capacity of 250 mAh g−1 after 2000 cycles with a capacity retention of 94%. In addition, the V2O5/CNTs film electrode also showed a high energy/power density (e.g., 67 kW kg−1/267 Wh kg−1). The capacitance response and rapid diffusion coefficient of Zn2+ (~10−8 cm−2 s−1) can explain the excellent rate capability of V2O5/CNTs. The vanadium pentoxide nanofibers/carbon nanotubes hybrid film as binder-free cathodes showed a high capability and a stable cyclability, demonstrating that it is highly promising for large-scale energy storage applications.