Zhang Yingjiu

Influences of Si and Ni Catalysts on the Growth of Boron Nanowires

Abstract Boron nanowires (BNWs) were synthesized using boron powders as boron source and, Si and Ni as catalysts. The diameter of boron nanowires is about 50 ∼ 100 nm and their length is up to several micrometers. The experiments show that Si promotes the growth of boron nanowires. Using Ni(NO 3 ) 2 as Ni sources rather than NiSO 4 produces more highly effective catalytic effects on the growth of nanowires. Additionally, the catalytic process will be improved by synthesizing Ni x B y catalysts before growth rather than simultaneously decomposing the metal salt and growing the boron nanowires (BNWs).

Self-powered nanosystems based on nanofuelcell

With the rapid progress in researches on nano-materials, a dramatically increasing number of nanoscale functional devices are developed, including nano-biosensors, nano-photoelectric sensors. Most of these nanoscale devices rely on external power supply to work sustainably. Although an energy storage unit is a choice for powering nanodevices, the large dimension of existed power sources has become one limited factor for the miniaturization of independently workable nanodevices. Therefore, a nanoscale power source capable of harvesting energy from the environment is an essential solution for building a “self-powered” nanosystem which is an integration of functional nanodevices and nano- enabled energy scavenging technologies. The successful development of such nanoscale power sources that match with nanodevices is significant for constructing self-powered nanosystems. The self-powered nanosystems will be widely used in industrial fields such as sensors networks, environmental and infrastructural monitoring, portable electronics, and healthcare. Referring to recent vigorously studies on exploiting self-powered nanosystems based on functional nanodevices and nano-batteries, it is obvious that the preparation of nano fuel cell is the key to the establishment of self-powered nanosystems. Fuel cells have many advantages over conventional batteries, such as high energy conversion efficiency, quick startup ability under low temperature, high energy density, and the feature of environmental friendly. What’s more, through the technical route of fuel cells, chemical and biochemical energy, the most abundant energy available in nature or in vivo biosystems, can be converted to electrical energy from fuels such as methanol and glucose, which is meaningful to the development of in vivo implantable nanosystems. Therefore, more and more attentions of the scientific community in fields of nanoenergy and nanosystems have been paid to the researches on micro and even nano scale miniaturization of fuel cells. Our group has done some studies on the proton exchange properties of single perfluorinated sulfonic acid resin (Nafion) nanowire, and on the nano proton exchange membrane fuel cells. We also have built a number of self-powered nanosystems based on such nano fuel cells. In this review article, we begin with the introduction to the proton exchange properties of Nafion nanowires, which is based on the works of our and other research groups. Then we briefly introduce nanofuel, nanobiofuel, hybrid nano biofuel cells, and self-powered nanosystems that are powered by these fuel cells, which represents a new self-powering approach in nanotechnology. We also briefly sum up the state of the art, point out confronting problems, and prospect possible trends in the researches on self-powered nanosystems. This work shows the feasibility of building self-powered nanosystems for biological sciences, environmental monitoring, defense technology and even personal electronics.

Applications of graphene-based materials in water treatment: mass transport and pollutants adsorption properties

Graphene-based nanomaterials have been used as separation membranes and adsorbents due to its unique two-dimensional single atomic layer structure, large specific surface area and excellent properties. In this paper, we first review gas, water and ions mass transport phenomenon through nanoporous graphene membranes and layered structures of graphene oxides. The development of nanoporous graphene has been limited by the current preparation technique and immature hole-drilling technology; while the laminated graphene oxide membranes have a great application potential in the field of water purification due to its simple, low-cost preparation methods, high permeability and selectivity. Then, we review the adsorption behaviors of heavy metal ions, dyes and organic pollutants in aqueous solution with graphene-based nanomaterials. The interaction mechanism between functional groups on graphene-based materials and pollutants has been analyzed. Finally, we prospect the opportunities and challenges of graphene-based nanomaterials in environmental applications, such as membrane separation, water desalination and pollutants removal.

TiO 2 /CdS同轴异质结的制备及光催化性能研究

本研究采用阳极氧化法在金属钛箔上制备TiO 2 纳米管阵列, 并用直流电沉积在退火后的TiO 2 纳米管内部填充CdS。用扫描电子显微镜(SEM)及电子能谱(EDS)、X射线衍射(XRD)对TiO 2 /CdS异质结进行表征, 结果显示, TiO 2 /CdS同轴核壳结构有序规整排列, 孔径大小均一, Cd、S两种元素化学配比接近1:1。450℃空气退火后的TiO 2 是锐钛矿型, 沉积的CdS为六方相。对TiO 2 纳米管和TiO 2 /CdS异质结分别进行了紫外–可见吸收光谱和紫外光下光催化降解甲基橙染料的性能测试。结果表明, 复合后TiO 2 的吸收边出现了明显的红移; TiO 2 /CdS催化降解甲基橙的降解率最高达99.4%, 与纯TiO 2 相比TiO 2 /CdS的光催化活性明显提高。本研究采用阳极氧化法在金属钛箔上制备TiO 2 纳米管阵列, 并用直流电沉积在退火后的TiO 2 纳米管内部填充CdS。用扫描电子显微镜(SEM)及电子能谱(EDS)、X射线衍射(XRD)对TiO 2 /CdS异质结进行表征, 结果显示, TiO 2 /CdS同轴核壳结构有序规整排列, 孔径大小均一, Cd、S两种元素化学配比接近1:1。450℃空气退火后的TiO 2 是锐钛矿型, 沉积的CdS为六方相。对TiO 2 纳米管和TiO 2 /CdS异质结分别进行了紫外–可见吸收光谱和紫外光下光催化降解甲基橙染料的性能测试。结果表明, 复合后TiO 2 的吸收边出现了明显的红移; TiO 2 /CdS催化降解甲基橙的降解率最高达99.4%, 与纯TiO 2 相比TiO 2 /CdS的光催化活性明显提高。