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Xiaomiao Feng

Bio: Xiaomiao Feng is an academic researcher from Nanjing University of Posts and Telecommunications. The author has contributed to research in topics: Graphene & Polyaniline. The author has an hindex of 37, co-authored 95 publications receiving 4888 citations. Previous affiliations of Xiaomiao Feng include University of California, Los Angeles & University of California, San Diego.


Papers
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Journal ArticleDOI
TL;DR: In this article, a large-scale electrochemical synthesis of graphene/polyaniline (PANI) composite films using graphite oxide (GO) and aniline as the starting materials was described.
Abstract: This work describes a new one-step large-scale electrochemical synthesis of graphene/polyaniline (PANI) composite films using graphite oxide (GO) and aniline as the starting materials. The size of the film could be controlled by the area of indium tin oxide (ITO). Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), and ultraviolet–visible absorption spectrum (UV–vis) results demonstrated that the graphene/PANI composite film was successfully synthesized. The obtained graphene/PANI composite film showed large specific area, high conductivity, good biocompatibility, and fast redox properties and had perfect layered and encapsulated structures. Electrochemical experiments indicated that the composite film had high performances and could be widely used in applied electrochemical fields. As a model, horseradish peroxidase (HRP) was entrapped onto the film-modified glassy carbon electrode (GCE) and used to construct a biosensor. The immobilized HRP showed a pair of well-defined redox peaks and high catalytic activity for the reduction of H2O2. Furthermore, the graphene/PANI composite film could be directly used as the supercapacitor electrode. The supercapacitor showed a high specific capacitance of 640 F g−1 with a retention life of 90% after 1000 charge/discharge cycles.

482 citations

Journal ArticleDOI
Xiaomiao Feng1, Changjie Mao1, Gang Yang1, Wenhua Hou1, Jun-Jie Zhu1 
22 Mar 2006-Langmuir
TL;DR: It was found that the electrical conductivity of the PANI/Au composite hollow spheres was more than 3 times higher than that of the pure PANI hollow spheres.
Abstract: Polyaniline (PANI)/Au composite hollow spheres were successfully synthesized using polystyrene/sulfonated polystyrene core/shell gel particle templates. The PANI shell thickness and the number of Au nanoparticles decorating the PANI could be controlled effectively by adjusting the experimental conditions. The morphology, composition, and optical properties of the resulting products were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet-visible absorption spectra. It was found that the electrical conductivity of the PANI/Au composite hollow spheres was more than 3 times higher than that of the pure PANI hollow spheres. Furthermore, PANI/Au composites were immobilized on the surface of a glassy carbon electrode (GCE) and applied to construct a sensor. The obtained PANI/Au-modified GCEs showed one pair of redox peaks and high catalytic activity for the oxidation of dopamine. The possible formation mechanism of the PANI/Au composite hollow spheres was also discussed.

336 citations

Journal ArticleDOI
TL;DR: In aqueous electrolytes, the 3D MnO2-CNT-graphene-Ni based prototype supercapacitors show specific capacitances of ~251 F g (-1) with good cycling stability at a current density of 1.0 A g(-1).
Abstract: Carbon nanotube (CNT)–graphene hybrids grown on porous Ni foam are used as substrates to immobilize MnO2 nanoflakes, thus forming three-dimensional (3D) MnO2–CNT–graphene–Ni hybrid foam. The as-prepared hybrid materials could be used as supercapacitor electrodes directly without any binder and conductive additives, and fully maintain the high conductivity and high surface-to-volume ratio of CNTs, large pseudocapacitance of MnO2 nanoflakes and high porosity provided by the framework of Ni foam. The conductivity of the 3D MnO2–CNT–graphene–Ni foam is as high as 117 S cm−1 due to the seamless integration of MnO2 nanoflakes, CNTs, graphene and Ni foam among the 3D frameworks, which guarantee its low internal resistance (1.25 ohm) when compacted into supercapacitor devices. In aqueous electrolytes, the 3D MnO2–CNT–graphene–Ni based prototype supercapacitors show specific capacitances of ∼251 F g−1 with good cycling stability at a current density of 1.0 A g−1. In addition, these 3D hybrids also demonstrate their potential in all-solid-state flexible supercapacitors.

312 citations

Journal ArticleDOI
TL;DR: Plant-based bioinspired magnetically propelled helical microswimmers are described, showing efficient propulsion, with a speed of over 250 μm/s, as well as powerful locomotion in biological media such as human serum.
Abstract: Plant-based bioinspired magnetically propelled helical microswimmers are described. The helical microstructures are derived from spiral water-conducting vessels of different plants, harnessing the intrinsic biological structures of nature. Geometric variables of the spiral vessels, such as the helix diameter and pitch, can be controlled by mechanical stretching for the precise fabrication and consistent performance of helical microswimmers. Xylem vessels of a wide variety of different plants have been evaluated for the consistency and reproducibility of their helical parameters. Sequential deposition of thin Ti and Ni layers directly on the spiral vessels, followed by dicing, leads to an extremely simple and cost-efficient mass-production of functional helical microswimmers. The resulting plant-based magnetic microswimmers display efficient propulsion, with a speed of over 250 μm/s, as well as powerful locomotion in biological media such as human serum. The influence of actuation frequencies on the swimmi...

312 citations

Journal ArticleDOI
TL;DR: The use of seawater as fuel to propel Janus micromotors, which utilize macrogalvanic corrosion and chloride pitting corrosion processes, eliminate the need for external fuels to offer efficient and prolonged propulsion towards diverse applications in aquatic environments.
Abstract: We describe the use of seawater as fuel to propel Janus micromotors. The new micromotors consist of biodegradable and environmentally friendly magnesium microparticles and a nickel–gold bilayer patch for magnetic guidance and surface modification. Such seawater-driven micromotors, which utilize macrogalvanic corrosion and chloride pitting corrosion processes, eliminate the need for external fuels to offer efficient and prolonged propulsion towards diverse applications in aquatic environments.

309 citations


Cited by
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TL;DR: The advent of AuNP as a sensory element provided a broad spectrum of innovative approaches for the detection of metal ions, small molecules, proteins, nucleic acids, malignant cells, etc. in a rapid and efficient manner.
Abstract: Detection of chemical and biological agents plays a fundamental role in biomedical, forensic and environmental sciences1–4 as well as in anti bioterrorism applications.5–7 The development of highly sensitive, cost effective, miniature sensors is therefore in high demand which requires advanced technology coupled with fundamental knowledge in chemistry, biology and material sciences.8–13 In general, sensors feature two functional components: a recognition element to provide selective/specific binding with the target analytes and a transducer component for signaling the binding event. An efficient sensor relies heavily on these two essential components for the recognition process in terms of response time, signal to noise (S/N) ratio, selectivity and limits of detection (LOD).14,15 Therefore, designing sensors with higher efficacy depends on the development of novel materials to improve both the recognition and transduction processes. Nanomaterials feature unique physicochemical properties that can be of great utility in creating new recognition and transduction processes for chemical and biological sensors15–27 as well as improving the S/N ratio by miniaturization of the sensor elements.28 Gold nanoparticles (AuNPs) possess distinct physical and chemical attributes that make them excellent scaffolds for the fabrication of novel chemical and biological sensors (Figure 1).29–36 First, AuNPs can be synthesized in a straightforward manner and can be made highly stable. Second, they possess unique optoelectronic properties. Third, they provide high surface-to-volume ratio with excellent biocompatibility using appropriate ligands.30 Fourth, these properties of AuNPs can be readily tuned varying their size, shape and the surrounding chemical environment. For example, the binding event between recognition element and the analyte can alter physicochemical properties of transducer AuNPs, such as plasmon resonance absorption, conductivity, redox behavior, etc. that in turn can generate a detectable response signal. Finally, AuNPs offer a suitable platform for multi-functionalization with a wide range of organic or biological ligands for the selective binding and detection of small molecules and biological targets.30–32,36 Each of these attributes of AuNPs has allowed researchers to develop novel sensing strategies with improved sensitivity, stability and selectivity. In the last decade of research, the advent of AuNP as a sensory element provided us a broad spectrum of innovative approaches for the detection of metal ions, small molecules, proteins, nucleic acids, malignant cells, etc. in a rapid and efficient manner.37 Figure 1 Physical properties of AuNPs and schematic illustration of an AuNP-based detection system. In this current review, we have highlighted the several synthetic routes and properties of AuNPs that make them excellent probes for different sensing strategies. Furthermore, we will discuss various sensing strategies and major advances in the last two decades of research utilizing AuNPs in the detection of variety of target analytes including metal ions, organic molecules, proteins, nucleic acids, and microorganisms.

3,879 citations

Journal ArticleDOI
07 Jul 2008-Polymer
TL;DR: In this paper, the technology involved with exfoliated clay-based nanocomposites and also include other important areas including barrier properties, flammability resistance, biomedical applications, electrical/electronic/optoelectronic applications and fuel cell interests.

2,917 citations

Journal ArticleDOI
TL;DR: In this paper, the authors reviewed several key issues for improving the energy densities of supercapacitors and some mutual relationships among various effecting parameters, and challenges and perspectives in this exciting field are discussed.
Abstract: In recent years, tremendous research effort has been aimed at increasing the energy density of supercapacitors without sacrificing high power capability so that they reach the levels achieved in batteries and at lowering fabrication costs For this purpose, two important problems have to be solved: first, it is critical to develop ways to design high performance electrode materials for supercapacitors; second, it is necessary to achieve controllably assembled supercapacitor types (such as symmetric capacitors including double-layer and pseudo-capacitors, asymmetric capacitors, and Li-ion capacitors) The explosive growth of research in this field makes this review timely Recent progress in the research and development of high performance electrode materials and high-energy supercapacitors is summarized Several key issues for improving the energy densities of supercapacitors and some mutual relationships among various effecting parameters are reviewed, and challenges and perspectives in this exciting field are also discussed This provides fundamental insight into supercapacitors and offers an important guideline for future design of advanced next-generation supercapacitors for industrial and consumer applications

1,761 citations