查找使用阿拉丁产品的科研文献

A core-shell MWCNT@rGONR heterostructure modified glassy carbon electrode for ultrasensitive electrochemical detection of glutathione

Qingyan Liu,Jing Bao,Mei Yang,Xiaojing Wang,Shiyu Lan,Changjun Hou,Yongzhong Wang,Huanbao Fa

In this work, a multiwalled carbon [email protected] graphene oxide nanoribbons core-shell heterostructure ( [email protected] )-modified glassy carbon electrode ( [email protected] /GCE) was employed to electrochemically detect glutathione (GSH). The morphologies and microstructures of the as-prepared [email protected] heterostructure were examined by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy spectrum (FT-IR), respectively. The electrochemical characteristics and catalytic behaviors of the fabricated sensor for determination of GSH were systematically investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), differential pulse voltammetry (DPV), and amperometry (i–t). Under optimum conditions, the [email protected] heterostructure modified electrode possesses the ability of strong electrocatalytic for GSH with high selectivity and sensitivity, fast response, wide linear range, low detection limit (39 nM) and outstanding reproducibility. Its further application for the quantification of GSH concentration in human serum samples was also demonstrated with satisfactory accuracy. These features indicate that the prepared core-shell [email protected] heterostructure with unique electronic structure offers an excellent biosensing platform for sensitive and selective detection of glutathione.

Crystallization and Dielectric Properties of MWCNT /Poly(1-Butene) Composite Films by a Solution Casting Method

Lingfei Li,Qiu Sun,Xiangqun Chen,Yongjun Xu,Zhaohua Jiang

In this work, poly(1-butene) (PB-1) composite films with multi-walled carbon nanotubes (MWCNT) were prepared by a solution casting method. The relationship between the dielectric properties and the crystal transformation process of the films was investigated. It was indicated that there were two crystal forms of I and II of PB-1 during the solution crystallization process. With the prolongation of the phase transition time, form II was converted into form I. The addition of the conductive filler (MWCNT) accelerated the rate of phase transformation and changed the nucleation mode of PB-1. The presence of crystal form I in the system increased the breakdown strength and the dielectric constant of the films and reduced the dielectric loss, with better stability. In addition, the dielectric constant and the dielectric loss of the MWCNT/PB-1 composite films increased with the addition of MWCNT, due to the interfacial polarization between MWCNT and PB-1 matrix. When the mass fraction of the MWCNT was 1.0%, the composite film had a dielectric constant of 43.9 at 25 °C and 103Hz, which was 20 times that of the original film.Keywords:poly(1-butene);multi-walled carbon nanotubes;solution crystallization;dielectric properties;breakdown strength

ZnPc-MWCNT/sulfonated poly (ether ether ketone) composites for high-k and electrical energy storage applications

Wenhan Xu,Yunhe Zhang,Gang Yang,Xiang Yu,Jie Liu,Zhenhua Jiang

Three-Dimensional Interconnected Porous Partially Unzipped MWCNT/Graphene Composite Aerogels as Electrodes for High-Performance Supercapacitors

Jun Zhou,Yuying Zheng,Dongyang Chen

The self-restacking of graphene nanosheets inevitably compromises the electrochemical performance of conventional graphene-based materials. Herein, to solve this problem, we prepared a new type of three-dimensional porous aerogel with partially unzipped multiwalled carbon nanotubes inserted into graphene nanosheets via a reduction-reaction-induced self-assembly process. In the resulting aerogels, the inner carbon nanotubes (CNTs) tightly attach to the unzipped outer graphene nanoribbons (GNRs), which bridge with the graphene nanosheets. These interconnections bring them excellent electrical contact; the CNTs act as spacers to prevent the restacking of adjacent graphene nanosheets, and the abundant interconnected pores in the aerogels provide large channels for charge transfer. Accordingly, the aerogels exhibit a specific capacitance of 348.4 Fg−1at a scan rate of 5 mVs−1, with capacitance retention remaining at 89.7% at a current density of 2 Ag−1after 5000 cycles. The results show that the aerogels are promising electrode materials for supercapacitor applications.Keywords:supercapacitor;aerogel;graphene;carbon nanotubes;nanoribbons

In Situ Fabrication of NiMn-LDH@MWCNT Composites with Hierarchical Structure for Superior Electrochemical Energy Storage

Yan Li,Bihao Hu,Bingbing Hu,Chuanlan Xu,Shu Yang,Jingjing Yu,Biao Zhang,Yuping Liu,Danmei Yu,Changguo Chen

Graphical Hierarchical NiMn-LDH@MWCNT composites , which are composed of NiMn-LDH nanosheets growing directly on MWCNT, have been synthesized in situ via one-step hydrothermal method. The composites possess excellent specific capacitive and rate performance, in which the electrochemical process is controlled by diffusion. The assembled NiMn-LDH-4//AC device exhibits the energy density of 51.5 Wh kg −1 at the power density of 455.7 W kg −1 and 83.9 % capacitance retention after 5000 cycles. As an electrochemical energy storage material, transition metal layered double hydroxides (MLDHs) have attracted attention due to tunable two-dimensional structure and low cost. In this study, NiMn-LDH@MWCNT composites with hierarchical structure have been successfully synthesized with simple and economical one-step hydrothermal method. The hierarchical structure of composites was formed by NiMn-LDH nanosheets growing directly on multiwall carbon nanotubes (MWCNTs). This design not only can maintain excellent network conductive channels, but also increase active sites, enlarge specific surface area, and reduce internal resistance. Our results show that the NiMn-LDH-4 composite exhibits an excellent electrochemical performance with an ultrahigh specific capacitance of 1863 F g −1 at a current density of 1 A g −1 and 1164 F g −1 when the current density goes up 10 times. This may be attributed to the synergy effect of the hierarchical structure and introduction MWCNT. Moreover, the assembled NiMn-LDH-4//AC device can provide a relatively high specific energy density of 51.5 Wh kg −1 at a high energy density of 455.7 W kg −1 and possess great cycling stability (83.9 % capacitance retention after 5000 cycles).

An Integrated Neural Optrode with Modification of Polymer-Carbon Composite Films for Suppression of the Photoelectric Artifacts

Yanyan Xu,Xien Yang,Zhiwen Liang,Lizhang Lin,Wenbo Zhao,Liyang Wang,Yu Xia,Xudong Lin,Mang I. Vai,Sio Hang Pun,Baijun Zhang

Optogenetics-based integrated photoelectrodes with high spatiotemporal resolution play an important role in studying complex neural activities. However, the photostimulation artifacts caused by the high level of integration and the high impedance of metal recording electrodes still hinder the application of photoelectrodes for optogenetic studies of neural circuits. In this study, a neural optrode fabricated on sapphire GaN material was proposed, and 4 μLEDs and 14 recording microelectrodes were monolithically integrated on a shank. Poly(3,4-ethylenedioxythiophene)/polystyrenesulfonate and multiwalled carbon nanotubes (PEDOT:PSS-MWCNT) and poly(3,4-ethylenedioxythiophene) and graphene oxide (PEDOT-GO) composite films were deposited on the surface of the recording microelectrode by electrochemical deposition. The results demonstrate that compared with the gold microelectrode, the impedances of both composite films reduced by more than 98%, and the noise amplitudes decreased by 70.73 and 87.15%, respectively, when exposed to light stimulation. Adjusting the high and low levels, we further reduced the noise amplitude by 48.3%. These results indicate that modifying the electrode surface by a polymer composite film can effectively enhance the performance of the microelectrode and further promote the application of the optrode in the field of neuroscience.

Near-infrared-triggered in situ hybrid hydrogel system for synergistic cancer therapy

Huijuan Zhang,Xiali Zhu,Yandan Ji,Xiaojing Jiao,Qianqian Chen,Lin Hou,Hongling Zhang,Zhenzhong Zhang

As one of the most frequently used chemotherapeutic drugs, doxorubicin (DOX) is accompanied by low accumulation in tumors and severe dose-limiting side effects with systemic administration, which limits its therapeutic index. In this work, a novel and injectable in situ photo-sensitive inorganic/organic hybrid hydrogel as a localized drug-delivery system was examined. It explored poly(ethylene glycol) double acrylates (PEGDA) as a polymeric matrix, DOX as a model drug, a TiO2@MWCNT nanocomposite as the photoinitiator and photosensitizer–photothermal agent for tumor therapy possessing a multi-mechanism using a single NIR laser. Briefly, a PEGDA solution containing DOX and TiO2@MWCNTs was injected into a tumor and rapidly gelled in vivo via a photo-crosslinking action triggered by a NIR laser. DOX release from the DOX/TiO2@MWCNTs/PEGDA hydrogel was sustained and long-lasting, over 10 days, indicating that the PEGDA gel acted as a drug depot. Simultaneously, a NIR laser light was adopted which can be absorbed and converted into reactive oxygen species (ROS) or local hyperthermia by TiO2@MWCNTs, leading to tumor cell death. This DOX/TiO2@MWCNTs/PEGDA hydrogel exhibited remarkable anti-proliferative activities against MCF-7 cancer cells in vitro. Experiments in vivo showed that a single intratumoral injection of this hydrogel with 808 nm laser irradiation was the most effective among all DOX formulations in the tumor-bearing mice models. There was a relatively small DOX distribution in normal tissues and much lower systemic toxicity than the control group (DOX-only). In general, it is believed that the novel photo-sensitive hybrid hydrogel system prepared in this study can afford high drug-loading, sustained and stable drug release, as well as repeated phototherapy of the tumor with the administration of a single dose.

High-sensitive electrochemical sensor for determination of Norfloxacin and its metabolism using MWCNT-CPE/pRGO-ANSA/Au

Zhenping Liu,Mingliang Jin,Jieping Cao,Juan Wang,Xin Wang,Guofu Zhou,Albert van den Berg,Lingling Shui

In this work, a high-sensitive electrochemical sensor of Norfloxacin (NFX) has been developed using a composite electrode of MWCNT-CPE/pRGO-ANSA/Au. MWCNT-CPE is the multi-walled carbon nanotubes (MWCNT) – carbon paste electrode (CPE). pRGO-ANSA means the partially reduced graphene oxide (pRGO) – 6-aminonaphthalene-2-sulphonic acid (ANSA) hybrid nanomaterials. Au represents gold nanoparticles. The electrochemical sensing of NFX was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and differential pulse voltammetry (DPV). Experimental results show that the combination of MWCNT-CPE/pRGO-ANSA/Au offers high electrical conductivity, large surface area and excellent electrocatalytic activity, being beneficial for electrochemical sensing performance. The calibration curves of NFX exhibit linear response in the NFX concentration range of 0.03–1.0 and 1.0–50.0   μM, with the limit of detection (LOD) of 0.016   μM (S/N   =   3). The fabricated sensors were successfully applied for detecting the presence of NFX in pharmaceutical formulations and rat plasma samples. The measured results were comparable with those obtained using ultrahigh performance liquid chromatography (UHPLC), indicating its high potential for applications in pharmaceutical analysis and clinical therapeutic drug monitoring.

Effect of transition metals (Ni and Co) in the methanol oxidation reaction electrocatalytic activity on Mo2C/MWCNT

Lei-Xin Mao,Lin Fu,Xin-Yu Zhang,Zhi-Feng Yan,Zhi-Hua Gao,Lei Liu,Wei Huang,Zhi-Jun Zuo

The direct methanol fuel cells still recognize Pt and Pd as efficient catalysts for the methanol oxidation reaction (MOR). Our previous study demonstrated the high activity and stability of the Mo 2 C/MWCNT catalyst for electrocatalytic MOR. To further enhance the performance of Mo 2 C/MWCNT, the second metals (Ni and Co) are introduced onto Mo 2 C/MWCNT. It is found that Ni-Mo 2 C/MWCNT exhibits the highest electrocatalytic MOR activity, with a current density of 192 mA cm −2 in 1 mol/L(M) KOH + 1 M CH 3 OH electrolyte at 0.6 V (vs. Hg/HgO). Additionally, the stability of Mo 2 C/MWCNT significantly improves after Ni doping (85.61 % vs. 76.19 %). Characterization results reveal a strong interaction between Ni species and Mo 2 C, with some Ni ions doping into Mo 2 C. Furthermore, the Ni-Mo 2 C nanoparticles are evenly dispersed on MWCNT , with nanoparticle sizes ranging from 5 to 10 nm. DFT results indicate a charge transfer from Mo 2 C to Ni, resulting in the shift of the d-band center of the surface away from the Fermi level. Moreover, the interface charge transfer resistances of Ni- Mo 2 C/MWCNT significantly decreased (7.2 vs. 20.0 Ω). As a result, the electrocatalytic MOR activity on Ni- Mo 2 C/MWCNT improved compared to Mo 2 C/MWCNT.

CTF/MWCNT hybrid multi-functional separator as high-efficiency polysulfide tamer for high-performance Li–S battery

Qing Xuan Shi,Chen Chang,Hui Jie Pei,Xin Guan,Liang Liang Yin,Xiao Lin Xie,Yun Sheng Ye

The lithium–sulfur (Li–S) battery holds great promising for the next-generation energy storage system due to its high theoretical specific capacity and energy density . However, the poor conductivity of sulfur species and the “shuttle effect” of polysulfides (PSs) severely limit the practical application of Li–S battery. Here, a large-scaled covalent triazine framework/multiwall carbon nanotube (CTF/MWCNT) hybrid used as a multi-functional separator modifier combining strong PSs-anchor ability of CTF with high electrical conductivity of MWCNT was proposed. The ordered porous structure and large specific surface area of CTF make it good physical trap ability for PSs shuttle, and the abundant pyridinic nitrogen groups of CTF render it effectively adsorb PSs by chemical sorption , while the high electrical conductivity of MWCNT can facilitate electron transfer . As it turns out that the multi-functional separator applied in Li–S battery shows significant enhancements in the utilization of sulfur, specific capacity, Columbic efficiency, rate capability (982 mAh g −1 at 2 C) and cycling stability (0.045% specific capacity loss per cycle at 1 C along 1000 cycles) as well as suppression of self-discharge and Li dendrite growth. Furthermore, it is practicable to incorporate the slurry cast multi-functional layer onto the commercial separator, which provides ideas for constructing advanced multi-functional separators for commercially viable Li–S battery.

Molecularly imprinted electrochemical sensor based on PEDOT-OH@au/MWCNT-OH composite for ultrasensitive detection of pefloxacin

Guoliang Zhang,Yaolong Zhang,Yu Zhang,Changshun Wang,Jin Tan,Ruxangul Jamal,Tursun Abdiryim,Ahmat Ali

Hydroxyl-functionalized MWCNs and PEDOT are better suited for loading MIP. • The sensor detects pefloxacin at the picomolar level. • Synthesis of ultra-thin tubular PEDOT-OH@Au/MWCNs-OH nanocomposites. • The excellent thin-layered structure offers an efficient electron transport pathway. To safeguard public health and prevent the increase of bacterial resistance, the creation of practical and accurate detection methods for the quantitative analysis of fluoroquinolone antibiotics is essential. In this study, a tubular PEDOT-OH@Au/MWCNTs-OH substrate material was prepared using a one-step in situ oxidation method, with chloroauric acid as the oxidant. Pyrrole (Py) was used as the functional monomer, and pefloxacin (PFX) as the template molecule, to ingeniously design a molecularly imprinted electrochemical sensor (MIP/PEDOT-OH@Au/MWCNT-OH) with sensitive sensing capabilities. As expected, the unique structure and properties of PEDOT-OH@Au/MWCNTs-OH provided the sensor more surface area and enhanced electrochemical activity, increasing the number of distinct recognition sites. Based on experimental results, the MIP/PEDOT-OH@Au/MWCNT-OH sensor showed good anti-interference and stability, a low detection limit of 0.149 nM, S/N = 3, and a broad linear range of 0.002–30 μM. Additionally, the sensor achieved a recovery rate of 97%–103% in detecting PFX in pefloxacin mesylate ointment. This sensor shows promise as a highly selective and sensitive portable detection method for the quantitative analysis of PFX in the environmental monitoring. Download: Download high-res image (239KB) Download: Download full-size image

Anode-Free Lithium Metal Battery Enabled by Oxygen-Functionalized MWCNT and TiN Interlayer for Uniform Lithium Deposition

Chaoyin Peng,Li Wang,Yin Li,Junxian Hu,Shaoze Zhang,Keyu Zhang,Jian Tang,Yunke Wang,Yaochun Yao

Anode-free lithium metal batteries (AFLMBs), with high energy density, low cost, and enhanced safety, are regarded as the next-generation high-energy-density batteries. However, capacity decay and uncontrollable dendritic Li growth hinder its practical adoption. Hence, a Cu@TiN-MWCNT interfacial layer was rationally designed on Cu foil to enable highly reversible Li deposition/stripping. TiN nanoparticles provide abundant lithiophilic sites to reduce the Li nucleation overpotential, while COOH-functionalized multi-walled carbon nanotubes construct a conductive network to decrease local current density and improve interfacial stability. Moreover, oxygen-containing carboxyl groups promote lithium salt dissociation and facilitate the formation of a LiF-rich solid electrolyte interphase, further stabilizing the electrode/electrolyte interface and suppressing dendritic Li growth. Benefiting from these synergistic effects, compact and uniform Li deposition is achieved. As a result, the Li/Cu@TiN-MWCNT||LFP cell with a low N/P ratio of 2.1 maintains a specific capacity of 144.15 mAh g −1 after 150 cycles at 3 C. Additionally, the AFLMB exhibits a high-capacity retention of 51.41% and coulombic efficiency of 98.67% after 80 cycles, which points out a new direction for the development of current collectors toward high-performance AFLMBs.