锡纳米微粒的摩擦学性能

液相分散;作用机理假设;锡纳米微粒的摩擦学性能     

PdO,Au, CdO修饰SnO2纳米纤维的制备及其气敏特性

采用静电纺丝的方法制备了SnO₂纳米纤维,并分别用PdO、Au、CdO对该纳米纤维材料进行表面修饰.用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线能谱(EDX)、X射线光电子能谱(XPS)分析、Brunauer-Emmett-Teller (BET)比表面积测试对材料进行表征.修饰前后, SnO₂纳米纤维都是由约15 nm的纳米颗粒构成的直径约为200 nm的多级结构材料.采用静态测试系统对纯SnO₂及不同物质修饰的SnO₂的气敏特性进行测试,结果表明,未修饰的SnO₂纳米纤维气敏元件对甲醛具有较好的响应.修饰后的SnO₂材料的气敏特性都有明显的改善. CdO修饰的SnO₂气敏元件对甲醛的响应值最高,且响应恢复时间短,选择性好. Au修饰的SnO₂气敏元件对甲醛响应的最佳工作温度从300 ℃降到了200 ℃.经PdO修饰后, SnO₂纳米纤维对甲苯的响应值变得最高.初步分析了经过修饰的SnO₂气敏材料的敏感机理.     

纳米晶镍-钼合金电沉积层的结构与性能

研究了Ｃｒ２Ｏ３、ＭｏＯ３、ＳＯ２－４和ＣｕＳＯ４在ＳｎＯ２表面的单层分散及其对ＳｎＯ２超细粉热稳定性的影响．结果表明,几种化合物在ＳｎＯ２上均能单层分散且分散阈值都接近按密置单层模型估算的分散容量极限值;表面单层覆盖能十分有效地抑制ＳｎＯ２的高温烧结,单层覆盖率与经５００℃焙烧后样品中ＳｎＯ２的粒径和比表面有很好的对应关系,表现出很强的阈值效应;单层覆盖率达到一定程度,ＳｎＯ２高温烧结便可基本得到抑制．     

掺镁YFeO3固溶体的电导和气敏性能研究

用化学共沉淀法制备了复合氧化物YFeO3镁掺杂固溶体Y1-xMgxFeO3气敏半导体材料,并对其相组成、电导和气敏性能进行了研究。结果表明：Mg2+在YFeO3的A位固溶范围为0糩]x糩0.8;电导测量显示,该p型固溶材料电导突变温度较纯相YFeO3低100℃以上;900℃下灼烧4h所得的Y0.94Mg0.06FeO3粉料制作的元件在257℃时对乙醇灵敏度最高,对4.5*mol/L乙醇的灵敏度高达44;选择性较好,4.5韒ol/LC2H5OH的灵敏度是45*mol/Lpetrol的4.0倍。     

Construction and Validation of Simple Magnetic Nanoparticle Detector Based on Giant Magnetoresistive Effect

The finding of giant magnetoresistive（GMR） effect develops a new field for the sensing application with magnetic nanoparticles（MNPs） labeling. A convenient GMR sensor was built with a permanent magnet to excite the MNPs in this work. The sensing element contained a Wheatstone bridge with the GMR material as one of its branches. The magnetic field from MNPs unbalanced the Wheatstone bridge. After being amplified, the output signals were recorded. The construction and optimization of the magnetoresistive sensing platform were discussed in detail. The detection of three kinds of MNPs validated the performance of the proposed GMR sensor. The sensor showed a fast response to the addition or removal of MNPs. Because of its simplicity, this kind of GMR sensor can be developed in a routine laboratory. The finding of this new GMR sensor will promote the development of the method of probing biomoleeules and the study on the biomolecular interaction after being labeled magnetically.     

A WO3 nanorod-Cr2O3 nanoparticle composite for selective gas sensing of 2-butanone

The sensor based on WO₃-Cr₂O₃ nanocomposites show good selectivity to 2-butanone.     

复合纳米粒子SnO2/CdS的制备及性能研究

由湿化学方法制备了包覆型SnO2 /CdS复合纳米粒子 .用ICP、XRD及TEM测定了样品的组成和平均晶粒尺寸 ,并通过HRTEM直接观察到样品的包覆结构 .与纯SnO2 纳米粒子相比较 ,SnO2 /CdS复合纳米粒子在波长为 36 0 - 5 80nm范围内有更强的吸收 ;由该复合纳米粒子制得的电极呈现出良好的光电转换特性 ,其最大IPCE值达 40 .9% ,远大于纯SnO2 纳米电极的IPCE( 0 .6 5 % ) ,而且光响应范围也从纯SnO2 的 30 0 - 4 0 0nm拓展到 30 0 - 5 5 0nm .     

Hydride Pinning Pathway in the Hydrogenation of CO2 to Formic Acid on Dimeric Tin Dioxide

Capture of CO₂ and its conversion into organic feedstocks are increasingly needed as society moves towards a renewable energy economy. Here, a hydride-assisted selective reduction pathway is proposed for the conversion of CO₂ to formic acid (FA) over SnO₂ monomers and dimers. Our density functional theory calculations infer a strong chemisorption of CO₂ on SnO₂ clusters forming a carbonate structure, whereas heterolytic cleavage of H₂ provides a new pathway for the selective reduction of CO₂ to formic acid at low overpotential. Among the two investigated pathways for reduction of CO₂ to HCOOH, the hydride pinning pathway is found promising with a unique selectivity for HCOOH. The negatively-charged hydride forms on the cluster during the dissociation of H₂ and facilitates the formation of a formate intermediate, which determines the selectivity for FA over the alternative CO and H₂ evolution reaction. It is confirmed that SnO₂ clusters exhibit a different catalytic behaviour from their surface equivalents, thus offering promise for future work investigating the reduction of CO₂ to FA via a hydride pinning pathway at low overpotential and CO₂ capturing.     

A high-sensitivity H2S gas sensor based on optimized ZnO-ZnS nano-heterojunction sensing material

This paper reports a high-performance H₂S gas sensing material that is made of ZnO nanowires (NWs) modified by an optimal amount of ZnS to form nano-heterojunctions. Compared with the intrinsic ZnO-NWs, the three differently modified nano-heterostructure material ZnO-ZnS-x (x = 5, 10, 15) shows significant improvement in sensing performance to H₂S at the working temperatures of 100−400 °C, especially in the low temperature range (<300 °C). The chemiresistive sensor with ZnO-ZnS-10 sensing-material exhibits the largest response signal to H₂S among all the other ZnO-ZnS-x (x = 5, 10, 15, 20) sensors. Its response signal to 5 ppm H₂S at 150 °C is about 2.7 times to that of the ZnO-NWs sensor. Besides, the ZnO-ZnS-10 sensor also features satisfactory selectivity and repeatability at 150 °C. With the technical advantage attributed to the reduction of the redesigned band gap at the interface between ZnO and ZnS, the ZnO-ZnS heterostructure sensor rather than the traditional ZnO-NWs sensor can be used for high-sensitivity application at low working temperature.     

导电聚合物传感器的研究进展

导电聚合物因其具有特殊的结构和优异的物理化学性能,而成为构建传感器的一种新材料。综述了近5年来导电聚合物在生物传感器、离子传感器、气敏传感器方面的研究进展,并对导电聚合物的研究动向作了展望。     

Palladium-Carbon Composite Nanoparticle Films with Enhanced Electrocatalytic Activity for Hydrogen Peroxide Sensors

A nanocomposite electrocatalyst was prepared with the method of cluster beam deposition of palladium nanoparticle thin lms on carbon nanoparticle supporting layers and used as sensitive nonenzyme hydrogen peroxide sensors. An enhancement on the electrocatalytic activity of the palladium nanoparticles toward H₂O₂ reduction was observed, which was related to the coverage of the carbon nanoparticles. With one monolayer of carbon nanoparticles, the H₂O₂ detection sensitivity reached the maximum, which was more than twice of that of the pure Pd nanoparticles.     

Preparation and Ethanol Sensing Properties of ZnO Nanofibers

ZnO nanofibers with an average diameter of about 90 nm were prepared by an electrospinning method combined with a calcination process. The as-electrospun nanofibers before and after calcination were characterized by means of differential thermal analysis(DTA), thermal gravimetric analysis(TGA), X-ray diffraction(XRD) and scanning electron microscopy(SEM). The fibers after calcination at 600 °C belong to the hexagonal wurtzite structure. The sensor based on ZnO nanofibers exhibited excellent ethanol sensing properties at 206 °C such as good linear dependence in the low concentration(1―100 μL/L), high response, and good selectivity. Fast response(less than 2 s) and recovery(about 16 s) were also observed in our investigations.     

镁掺杂对In2O3电导和气敏性能的影响

用共沉淀法制备了Mg2+掺杂的In2O3纳米粉,研究了镁掺杂对In2O3电导和气敏性能的影响.结果表明:MgO和In2O3间可形成有限固溶体In2-xMgxO3(0≤x≤0.40);MgIn×电离的空穴对材料导带电子的湮灭,使掺镁纳米粉的电导变得很小;n(Mg2+):n(In3+)=1:2共沉淀物于900℃下热处理4 h,用所得的纳米粉制作的传感器在320～370℃下,对45μmol/L C2H5OH的灵敏度达102.5,为相同浓度干扰气体Petrol的12倍多.     

(Sn,Sb)O2-x基纳米结构厚膜材料气敏特性及机理

对采用水热合成技术所形成的纳米(Sn,Sb)O2 x晶粒结构、厚膜材料的气敏特性及其机理进行了研究,并采用XRD、TEM手段对纳米尺度的（Sn、Sb)O2 x晶粒的结构与表面效应及晶粒形态进行了表征.结果表明,当掺杂Sb5＋的浓度（摩尔分数xSb5＋)为（2.9～5.8)×10－6时,（Sn、Sb)O2 x纳米晶粒表面的电子缺陷浓度增大,增强了对气体的吸附能力,从而提高了对可燃性气体的灵敏度.同时可使晶粒保持短柱状的形态特征,对其灵敏度有一定的控制作用.     

新型二氧化硫气体电化学传感器的研究

SO2 是大气的主要污染物 ,并能与环境中的 NOx,O3等协同作用 ,产生更严重的污染 .因此 ,SO2的测定在环境保护、职业健康、工业排放控制等方面起着非常重要的作用 .SO2 的测定方法包括气相色谱法 [1]、离子色谱法 [2 ]、电导测定 [3]和电解电导率 [4]、光纤传感器 [5 ,6 ]等 ,但这些方法所需仪器昂贵、操作繁琐、灵敏度较低、难以实时连续测定 .一些研究者致力于 SO2 电化学传感器的开发 [7～ 8] ,但存在着灵敏度低、需在高温下使用、稳定性差等缺点 .我们成功地研制了一种微型 SO2 气体电化学传感器 ,该传感器稳定性好、灵敏度高、价…     

聚合物/无机纳米粒子复合膜在气体分离中的研究进展

由于聚合物膜具有可高度设计、机械性能好、易于加工 等优点,是理想的气体分离材料。然而,聚合物膜在气体选择性和渗透性方面存在平衡限制,在聚合物中引入纳米粒子,是提高气体分离性能的一种有效手段。本文基于聚合物/无机纳米粒子复合膜在气体分离领域的研究现状,重点阐述了零维纳米粒子（二氧化硅、二氧化钛）、一维纳米粒子（碳纳米管）、二维纳米粒子（氧化石墨烯、二维过渡金属氧化物）、三维纳米粒子（金属有机框架、沸石）对气体分离性能的影响,并展望了聚合物复合分离膜的发展趋势,为未来高效分离膜的研发提供了参考。     

Electrochemical Performance Studies of Tin Oxide Prepared by Sol-Gel

IntroductionSince the introduction of commercial lithium-ion batteries for the portable devices in the 1 990′s,the search for new anode materials with improvedenergy density and cycle- ability has never beenstopped[1— 5] .Graphite used as the early commercialanode material for lithium- ion batteries over otherkinds of materials in terms of its flat intercalationpotential and high cycle- ability[6,7] can′t keep pacewith the demand today because of its low capacity.In resentyears,the greateff…     

Highly Selective Photoelectroreduction of Carbon Dioxide to Ethanol over Graphene/Silicon Carbide Composites

Using sunlight to produce valuable chemicals and fuels from carbon dioxide (CO₂), i.e., artificial photosynthesis (AP) is a promising strategy to achieve solar energy storage and a negative carbon cycle. However, selective synthesis of C₂ compounds with a high CO₂ conversion rate remains challenging for current AP technologies. We performed CO₂ photoelectroreduction over a graphene/silicon carbide (SiC) catalyst under simulated solar irradiation with ethanol (C₂H₅OH) selectivity of>99 % and a CO₂ conversion rate of up to 17.1 mmol g_cat⁻¹ h⁻¹ with sustained performance. Experimental and theoretical investigations indicated an optimal interfacial layer to facilitate the transfer of photogenerated electrons from the SiC substrate to the few-layer graphene overlayer, which also favored an efficient CO₂ to C₂H₅OH conversion pathway.     

CdS纳米粒子的表面修饰及其对光学性质的影响

用反胶束法合成了用表面活性剂分子磺基焉珀酸双－２－乙基已酯钠盐（ＡＯＴ）进行表面修饰的ＣｄＳ纳米粒子（记为ＣｄＳ／ＡＯＴ－ＳＯ３＾－）,研究了这种纳米粒子在正庚烷（ｈｅｐｔａｅ）和吡啶（Ｐｙ）溶剂中的荧肖及光解行为,发现其在正庚烷中荧光很强,而Ｐｙ却强烈地猝灭ＣｄＳ纳一子的荧光,用电荷转移猝灭机制进行了解释,这种解释为ＣｄＳ纳米粒子在Ｐｙ中光解实验进一步证实。     

纳米晶氧化锡的水热合成与表征

以水热法合成了高比表面积的纳米晶SnO_2粉体，运用FT-IR，XRD，BET，TEM 等手段对粉体的晶化过程进行了分析表征。FT-IR显示120 ℃水热得到的粉体即实 现水合锡化合物的晶化。XRD分析表明所得粉体均匀数纳米，且随水热温度的提高 ，晶粒长大。水热粉体均具有很高的比表面积。TEM显示粉体呈单分散状态。将水 热粉体进行热处理，粉体则长大较快，比表面积降低，分散性能出现反常改善。