Fabrication of a transparent ultraviolet detector by using n-type Ga(2)O(3) and p-type Ga-doped SnO(2) core-shell nanowires

This study investigates the feasibility of synthesizing high-density transparent Ga(2)O(3)/SnO(2):Ga core-shell nanowires on a sapphire substrate at 1000 °C by VLS. The doping Ga concentrations are 0.46, 1.07, 2.30 and 17.53 atomic%. The XRD spectrum and HR-TEM reveal Ga(2)O(3) and SnO(2) as having monoclinic and tetragonal rutile structures, respectively. Experimental results indicate that the XRD peak shift of SnO(2) to a larger angle increases with the increasing amount of Ga doping. According to the CL spectrum, SnO(2) and Ga(2)O(3) peak at approximately 528-568 nm and 422-424 nm, respectively. The maximum quantum efficiency of Ga(2)O(3)/SnO(2):Ga core-shell nanowires is around 0.362%. The UV light on-off current contrast ratio of Ga(2)O(3)/SnO(2):Ga core-shell nanowires is around 1066.7 at a bias of 5 V. Moreover, the dynamic response of Ga(2)O(3)/SnO(2):Ga core-shell nanowires has an on-off current contrast ratio of around 16. Furthermore, the Ga(2)O(3) region functions similar to a capacitor and continues to accumulate SnO(2):Ga excited electrons under UV light exposure.     

TiO2/SnO2复合薄膜的光催化活性研究

采用溶胶-凝胶法常温合成含有一定晶型的TiO2溶胶和SnO2溶胶,使用浸渍提拉法在普通载玻片上制备出TiO2/SnO2复合膜。考察了不同SnO2薄膜层数对TiO2/SnO2复合膜光催化活性的影响,并对其光催化活性提高的机理进行了探讨。结果表明,SnO2层的加入能有效提高薄膜的光催化活性,这是由于SnO2的导带电位低于TiO2的导带电位,其价带电位高于TiO2的价带电位,光激发下,TiO2中产生的光生电子注入到SnO2层,有效抑制了薄膜内电子-空穴对的复合,增加了复合薄膜表面空穴的浓度,因而光催化活性得到了显著的提高。     

二甲醚催化氧化制下游产品(Ⅱ)V/Mn改性的SnO2/MgO催化氧化制碳氢化合物

考察了SnO2/MgO催化剂和添加助剂V、Mn对二甲醚（DME）催化氧化制取乙二醇二甲醚（DMET）和其他碳氢化合物的催化性能。结果表明，锡镁催化剂对DME在275～325 ℃有良好的催化活性；添加VOx能较大提高DME转化率和产物DMET的选择性，DME转化率可达23％，DMET选择性可达44％，在300℃收率达9％以上。     

不同金属氧化物膜电极上苯酚的电催化氧化

分别以自制的金属氧化物膜电极Ti/SnO2+Sb2O3、Ti/SnO2+Sb2O3/PbO2和Ti/SnO2+Sb2O3/RuO2+PbO2为阳极，恒电流电解低浓度苯酚溶液，研究了不同金属氧化物阳极对苯酚电催化氧化过程的影响。实验结果表明：在实验条件下，苯酚溶液在3种金属氧化物膜电极上的电催化氧化过程的宏观动力学符合一级反应动力学规律，但不同金属氧化物阳极上苯酚电催化氧化过程的表观反应速率及电流效率有明显的差异。25℃下苯酚在Ti/SnO2+Sb2O3、Ti/SnO2+Sb2O3/PbO2和Ti/SnO2+Sb2O3/RuO2+PbO2电极上电催化氧化的表观反应速率常数k分别为6.66×10-2min-1、2.49×10-2min-1和9.76×10-3min-1;瞬时电流效率随电解时间的增长而下降，初始电流效率分别为78.7%、38.9%、13.2%。以Ti/SnO2+Sb2O3电极为阳极电解60 min后，苯酚浓度从初始浓度2.13×10-3mol·L-1降至3.27×10-5mol·L-1，苯酚的转化率达98.5%;而在相同的反应条件下，以Ti/SnO2+Sb2O3/PbO2和Ti/SnO2+Sb2O3/RuO2+PbO2为阳极时，苯酚的转化率只有82.7%和29.8%。对3种电极在苯酚溶液中的伏安特性的研究表明，Ti/SnO2+Sb2O3电极具有比Ti/SnO2+Sb2O3/PbO2和Ti/SnO2+Sb2O3/RuO2+PbO2高的析氧电位，因此有利于有机物的氧化和过程电流效率的提高。     

Controlled synthesis of magnetic iron oxides@SnO2 quasi-hollow core-shell heterostructures: formation mechanism, and enhanced photocatalytic activity

Iron oxide/SnO(2) magnetic semiconductor core-shell heterostructures with high purity were synthesized by a low-cost, surfactant-free and environmentally friendly hydrothermal strategy via a seed-mediated method. The morphology and structure of the hybrid nanostructures were characterized by means of high-resolution transmission electron microscopy and X-ray diffraction. The morphology evolution investigations reveal that the Kirkendall effect directs the diffusion and causes the formation of iron oxide/SnO(2) quasi-hollow particles. Significantly, the as-obtained iron oxides/SnO(2) core-shell heterostructures exhibited enhanced visible light or UV photocatalytic abilities, remarkably superior to as-used α-Fe(2)O(3) seeds and commercial SnO(2) products, mainly owing to the effective electron hole separation at the iron oxides/SnO(2) interfaces.     

不同金属氧化物阳极上甲基橙的电化学氧化降解

分别以Ti/SnO2+Sb2O3和Ti/SnO2+Sb2O3/PbO2电极为阳极进行甲基橙的电化学氧化,研究了两种金属氧化物阳极上甲基橙氧化降解过程的反应速率、电流效率及COD的变化.结果表明,两种金属氧化物阳极都能有效氧化降解甲基橙,氧化反应符合一级反应动力学规律,在Ti/SnO2+Sb2O3和Ti/SnO2+Sb2O3/PbO2电极上甲基橙氧化降解过程的表观速率常数分别为0.148和2.43×10-2 min-1. 以Ti/SnO2+Sb2O3为阳极电解30 min,甲基橙的浓度从初始时的0.305 mmol/L降至4.89×10-3 mmol/L,甲基橙的转化率达98.4%;在Ti/SnO2+Sb2O3/PbO2电极上,相同电解时间下甲基橙的浓度只降至0.14 mmol/L,转化率为55.0%. 对不同电极上甲基橙电化学氧化过程电流效率的研究表明,Ti/SnO2+Sb2O3电极的电流效率明显高于Ti/SnO2+Sb2O3/PbO2电极. Ti/SnO2+Sb2O3电极的反应速率大、电流效率高主要源于其较高的析氧电位.     

核壳结构SiO_2/SnO_2纳米复合微粒的合成与表征

文章从TEOS出发,先水解制备了纳米二氧化硅微粒,再以五水四氯化锡为锡源,碳酸铵为沉淀剂,通过控制反应条件,用共沉淀法在二氧化硅表面包覆上一层锡化物层,经600℃煅烧2 h后形成了具有核壳结构的SiO2/SnO2纳米复合微粒,并用透射电镜、激光粒度仪、FTIR等手段对其形貌、结构、组成进行了表征。结果表明：形成的核壳结构SiO2/SnO2纳米复合微粒是以二氧化硅为核,氧化锡为壳,内核直径约为120 nm,壳层厚度为8～18 nm;氧化锡基本以成膜包覆为主,伴有部分氧化锡自身成核团聚。     

水热法制备稀土元素掺杂二氧化锡及其对乙醇气敏性能

利用水热法制备了SnO2粉末及掺杂不同稀土离子的SnO2粉末. 通过XRD和气敏测试仪对其结构和性能进行了表征和测试. 结果表明,所制备的SnO2粉末呈四方金红石结构,稀土离子的掺入并没有改变SnO2的晶体结构,也无新晶相的出现. 掺杂镧的SnO2样品(SnO2:La)对乙醇有较高的气敏性. 分析了气敏机理. SnO2:La的灵敏度随着乙醇浓度的增加而增加,随温度的升高呈现波动状,且当温度在250℃时,SnO2:La对1.00′10-4乙醇的灵敏度最大,可达到101.1. 在此条件下其响应时间和恢复时间约为5 s.     

Polyethylene glycol-directed SnO2 nanowires for enhanced gas-sensing properties

SnO(2) nanowires with lengths in the tens of micrometres range have been synthesized on a large scale via a facile polyethylene glycol-directed method at ambient temperature followed by a suitable thermal treatment of the precursor nanowires. The morphology of the precursor of the SnO(2) nanowires is tunable by changing the concentration of either SnCl(2) or polyethylene glycol. After calcination, the resulting SnO(2) nanowires retain a similar shape to the precursor, but with hierarchical architecture, which can be considered as one-dimensional nanowires assembled by interconnected SnO(2) nanoparticles with a high surface-to-volume ratio. The SnO(2) nanowires are investigated with XRD, SEM, TEM, and gas sensing tests for detecting CO and H(2). It is found that the present SnO(2) nanowires exhibit a remarkable sensitivity and low detection limit (10 ppm for H(2)), as well as good reproducibility and short response/recovery times, which benefit from the unique hierarchical structure with a high surface-to-volume ratio and the 3D network formed by the nanowires.     

Effects of annealing on wettability and physical properties of SnO thin films deposited at low RF power densities

The SnO thin films were deposited at low RF power densities by RF magnetron sputtering. According to XRD and XPS analyses, the SnO thin film comprised nanocrystalline orthorhombic SnO with a (110) orientation. Reducing RF power density resulted in better nanocrystallinity, changing hydrophobicity to hydrophilicity, and increasing the optical transmission in the UV–vis–NIR region. After annealing, the SnO thin film favored p-type conductivity and hydrophilicity. As the annealing temperature increased, the coexistence of nanocrystalline orthorhombic SnO and tetragonal SnO₂ in the film clearly increased the optical transmission in the ultraviolet region. The SnO thin films after annealing at 500 ℃ in vacuum and N₂ (200 sccm) exhibited a higher hole mobility and a better optical selection in the ultraviolet region, respectively.     

rGO-SnO2纳米复合物制备及室温下NH3气敏性能

采用沉淀-焙烧法制备了室温下对NH3具有高灵敏度和高选择性的rGO-SnO2纳米复合材料。利用X射线衍射（XRD），傅里叶红外光谱（FTIR），X射线光电子能谱（XPS），扫描电子显微镜（SEM），透射电子显微镜（TEM）和比表面积（BET）表征分析了纯SnO2与rGO(1.0%)-SnO2纳米复合物的属性。与纯SnO2相比，rGO(1.0%)-SnO2纳米复合物中SnO2晶体尺寸较小，约为6~20nm，比表面积更大，为33m2/g；rGO(1.0%)-SnO2纳米复合材料对0.01% NH3的灵敏度达到了49.6%，是相同NH3浓度下纯SnO2灵敏度的2.1倍，并且响应和恢复时间分别为21s和204s，比纯SnO2缩短了24s和10s，具有良好的重复性，选择性与稳定性；rGO(1.0%)-SnO2纳米复合材料优良的气敏性能是由rGO与SnO2产生的p-n异质结以及溶解的NH3电离出导电离子共同作用的结果。     

Service life of Ti/SnO2–Sb2O5 anodes

The service life of SnO2–Sb2O5 coated anodes prepared by the spray pyrolysis technique using Ti or Ti/IrO2 substrate, was studied under galvanostatic conditions (100mAcm–2 in 1m H2SO4 at 25°C. The results showed that the presence of an IrO2 interlayer between the Ti substrate and the SnO2–Sb2O5 coating (Ti/IrO2/SnO2–Sb2O5 anode) strongly increases the service life of the anode. This beneficial action of the IrO2 interlayer was attributed to its high anodic stability and its isomorphous structure with TiO2 and SnO2. Cyclic voltammetry and steady-state polarization curves showed that the electrochemical behaviour of the Ti/IrO2/SnO2–Sb2O5 electrode lies between the behaviour of the Ti/IrO2 and the Ti/SnO2–Sb2O5 electrodes due to incorporation of IrO2 in the SnO2–Sb2O5 coating during its preparation.     

Morphological and phase control of tin oxide single-crystals synthesized by dissolution and recrystallization of bulk SnO powders

Various types of tin oxide particle, including square SnO platelets, truncated octahedral SnO crystals, and monodispepersed SnO₂ nanoparticles, were synthesized by the dissolution and recrystallization of bulk SnO powder via the thermal decomposition of tin oleate in a coordinating solvent of tri-n-octylamine at 340 °C. The results reveal that the atmosphere and reaction time are important factors that affect the shape of tin(II) oxide and the oxidation state of tin(II or IV) oxide. As tin oleate decomposed in a N₂ atmosphere, truncated octahedral SnO crystals formed. When the thermal decomposition was conducted in air, square SnO platelets formed after a 30-min reaction time. When the reaction time was extended to 180 min, the square SnO platelets decomposed and transformed into nanocrystalline SnO₂ particles.     

Ti/SnO2+Sb2O3/PbO2电极在硫酸溶液中Cr3+氧化的电化学性能

对用聚合前驱体溶液通过热分解法制备的Ti/SnO2+Sb2O3/PbO2电极在硫酸溶液中Cr3+电化学氧化的电化学性能进行了研究. 分别测定了以Ti/SnO2+Sb2O3/PbO2和PbO2为阳极，硫酸介质中Cr3+电化学氧化过程的极化曲线、抗腐蚀性以及不同操作电流密度、Cr3+浓度、反应温度、硫酸浓度下的电流效率. 实验结果表明，聚合前驱体溶液通过热分解法制备的Ti/SnO2+Sb2O3/PbO2电极与PbO2电极相比具有更高的电催化活性和抗腐蚀性.     

Biomineralized Sn-based multiphasic nanostructures for Li-ion battery electrodes

A method for preparing multiphasic hollow rods consisting of nanoscale Sn-based materials through a thermochemical reduction process involving bacteria and Sn oxides is reported. This facile process involves the bacteria-mediated synthesis of SnO(2) nanoparticles that form on bacterial surfaces used as templates at room temperature. The subsequent template removal proceeds via a reduction of the heat-treated SnO(2) nanoparticles at 400 °C under reduction atmosphere, leaving free-standing hollow nanocomposite rods. These unique hollow nanocomposite rods have multiple components, including amorphous carbon, metal oxides (SnO(2) and SnO), and metallic Sn, and retain the original rod shapes. The systematic phase and morphological evolutions of the bacteria@SnO(2) composite rods are investigated by performing controlled thermochemical reduction at various temperatures. In addition, the application of multiphasic hollow nanocomposite rods as anode materials for rechargeable Li-ion batteries is evaluated. These materials exhibit excellent electrochemical performance, with capacities of about 505 and 350 mA h g(-1) at current densities of 157 and 392 mA g(-1), respectively.     

Cu掺杂SnO2纳米粉体的制备及气敏特性

控制不同n(Cu2+)/n(Sn4+),用均匀共沉淀法制备了平均粒径约80 nm的金红石型结构Cu掺杂SnO2纳米粉体;并以白云母为基片制备出Cu掺杂SnO2气敏元件。用TG-DSC、XRD、SEM对样品的相变、结构、形貌进行了分析,并测试了气敏元件的阻温特性和75℃氢气敏感性能。结果表明,Cu掺杂抑制了SnO2晶核的生长,使SnO2结晶度由约75%减小到50%,晶粒尺寸由约18 nm减小到6 nm;Cu掺杂使n型半导体SnO2的空气电阻值由1~8 kΩ提高到9×105~3×107MΩ,并使元件在75℃对体积分数为2 000×10-6氢气的灵敏度提高约20倍;n(Cu2+)/n(Sn4+)≈0.01时,元件对体积分数为4 000×10-6氢气的灵敏度高达约42。     

SnO2纳米粒子的溶剂热制备及光致发光性质

以SnCl4·5H2O为原料,乙二胺为溶剂,用溶剂热法在180℃合成了SnO2纳米粒子,用XRD和TEM对其结构和形貌进行了表征,对SnO2纳米粒子的红外谱图、漫反射谱图以及光致发光性能进行了分析,探讨了乙二胺辅助合成SnO2纳米粒子的化学原理和生长机制。结果表明,用乙二胺辅助成长法合成的SnO2纳米粒子的粒径在40nm左右,粒径分布均匀,分散性较好。SnO2纳米粒子光致发光在340、432和672nm处有3个强峰,在472和540nm处有2个弱峰,其中340nm处的峰为紫外近带边激子发射峰,432、472和540nm处的峰是由氧缺陷引起的,672nm处的峰归因于表面态的氧缺陷引起的能带中深能级跃迁。     

二氧化锡不同掺杂方式对钛酸钡介电性能的影响

研究了二氧化锡不同掺杂方式对钛酸钡介电性能的影响。采用固相法制备出掺杂比例为2mol%SnO2&BaO、2mol%SnO2和4mol%SnO2三组不同方式SnO2掺杂钛酸钡样品。结果表明,两种掺杂方式对钛酸钡的作用效果截然不同,SnO2-BaO共掺杂会以BaSnO3的形式固溶入钛酸钡晶格,从而增大其介电常数,减小居里温度,同时介电损耗不会增大;SnO2单独掺杂则会引入Sn4+杂质离子,造成钛酸钡介电常数的减小以及介电损耗的增大,导致介电性能的劣化。     

掺杂Sb2O3的SnO2基陶瓷的SPS制备及性能研究

采用放电等离子烧结技术(SPS)制备了掺Sb2O3的SnO2基陶瓷.研究了烧结温度及Sb2O3的含量对SnO2基陶瓷的密度、物相、结构和电学性能的影响.研究袭明:随着烧结温度的提高,SnO2基陶瓷的相对密度逐渐增大,室温电阻率璧先减小后增大的趋势;随着Sb2O3掺杂量的增加,样品的相对密度呈先增加后减小的趋势,室温电阻...     

Sb掺杂SnO_2表面富集光电子能谱研究

采用化学共沉淀法,以SnCl4.5H2O和SbCl3为原料,成功地制备了5～20 nm左右、四方金红石Sb掺杂SnO2（ATO）微晶粉体。电阻率,XRD、XPS综合测试分析表明：Sb掺杂量、煅烧温度对Sb在SnO2晶粒中的分布、Sb价态的存在形式、电阻率的变化有较大的影响。掺杂到SnO2粉体中的Sb含量,不会改变SnO2的四方金红石结构,一部分Sb原子固溶到SnO2晶格中,剩余的Sb原子向SnO2粉体表面富集,并取代SnO2表面的Sn原子,形成Sb富集层,相当于一层＂栅栏＂,阻碍心部Sb原子向表面扩散,抑止掺杂SnO2（ATO）晶粒的长大。