Pd掺杂SnO2纳米颗粒的合成、表征和气敏特性（英文）

利用非模板水热法合成了Pd掺杂的SnO2纳米颗粒,并利用透射电镜(TEM)、X射线衍射(XRD)和X光电子能谱(XPS)表征了Pd掺杂对晶体结构、表面形貌、微观结构、热稳定性和表面化学状态的影响。研究发现:水热过程中Pd掺杂对形成的SnO2纳米颗粒大小几乎没有影响,在500°C以下的煅烧过程中,掺杂的Pd可以有效抑制颗粒的生长,但在700°C以上时颗粒生长迅速。XPS结果显示合成样品中Pd的化学状态有三种:Pd0、Pd2+和Pd4+,其中的主化学状态Pd4+有效促进了气敏性能的提高。为了同时提高气敏性能和热稳定性,Pd的最佳掺杂量为2.0%?2.5%(摩尔分数)。     

贵金属对SnO2气敏元件特性的影响

SnO2气敏元件近年来在国内外仍进行较多研究,以SnO2为基料并掺入适当的添加剂改善其气敏性能是目前研究的一个热点。作者介绍了近年来通过掺入不同种类的贵金属及控制热处理温度,提高SnO2气敏元件的灵敏度和选择性的工作,并探讨了添加剂对SnO2气敏元件特性的作用机理。     

Ag掺杂SnO_2纳米粉体的合成与抗菌性能研究

采用水热法制备得到了Ag掺杂SnO2纳米粉体。以XRD、BET、TEM等手段对粉体进行了表征。研究发现,200℃水热合成得到的SnO2纳米粉体的晶粒尺寸为数纳米,Ag离子的掺杂抑制了SnO2晶粒的长大。经600℃热处理后,纳米粉体的晶粒明显长大,分散性能良好。抗菌测试显示,直接水热法制得的Ag掺杂SnO2纳米粉体的抗菌能力较差,而经过600℃热处理后的粉体具有优良的抗菌性能。     

室温球磨固相法制备镧掺杂纳米二氧化锡及其性能研究

以SnCl2.2H2O、C2H2O4.2H2O和La(NO3)3.6H2O为主要原料,采用室温球磨固相法制备La3+掺杂纳米SnO2。利用X射线衍射仪、扫描电镜、紫外分光光度计等分析方法,研究了掺杂量、焙烧温度对粉体粒径、吸收率的影响。结果表明,La3+的掺杂抑制SnO2晶粒的长大,并且随其含量的增加,抑制SnO2长大的效果更明显;La3+的掺杂明显降低了粉体对紫外光的反射能力,增加了粉体对紫外光的吸收能力;在焙烧温度为700℃、La3+掺杂量为2wt%时,得到了对紫外光吸收率最好的粉体。     

镍离子掺杂TiO2涂层的制备及亲水性研究

目的 研究不同含量的镍离子掺杂对TiO2纳米涂层亲水性能的影响.方法 采用溶胶-凝胶法制备不同含量Ni2+掺杂TiO2纳米复合溶胶,通过浸渍提拉法在载玻片上成膜,经过热处理后,得到不同含量Ni2+掺杂TiO2复合涂层.通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、紫外-可见光分光光度计(UV-Vis)、傅里叶变换红外光谱仪(FT-IR)和表面接触角仪,对掺杂不同浓度Ni2+后TiO2的晶型、涂层微观形貌、光吸收性能、结构组成和涂层亲水性等进行表征分析,从而确定最佳Ni2+浓度的复合涂层材料配方.结果 制备的TiO2主要由锐钛矿相和少量金红石相组成,Ni掺杂抑制了锐钛矿相向金红石相的转变.随着Ni含量的增加,TiO2晶粒尺寸逐渐降低.适量掺杂Ni2+制备的TiO2纳米涂层表面形貌光滑,粒子分布致密均匀.掺杂使吸收波长阈值向长波方向偏移,禁带宽度减小,在一定程度上提高了TiO2涂层的亲水性.当Ni2+掺杂质量分数为1.5％时,TiO2涂层亲水性最佳.结论 采用溶胶-凝胶法实现了镍离子掺杂TiO2的改性,掺杂Ni2+后,Ni2+/TiO2复合涂层的亲水性能明显提高.     

钛基SnO2+SbOx电极固溶体生长活化能及作用机制

采用热分解法制备SnO2+SbOx钛基氧化物电极,利用TG/DTA、XRD和XPS等手段对SnO2+SbOx固溶体进行表征,计算SnO2+SbOx固溶体的生长活化能,并探讨SnO2+SbOx固溶体的作用机制,同时采用快速寿命法考察氧化物电极在0.5 mol/L H2SO4溶液中2 A/cm2下的预期使用寿命。结果表明： Sb掺杂SnO2形成的N型半导体和P型半导体产生的自由电子和氧空位使得电极导电性增强,预期使用寿命增加为30 h,晶粒表面氧空位的存在和非常低的晶间旋转驱动力是导致SnO2+SbOx固溶体的生长活化能降低为12.63 kJ/mol的主要原因。因此,Sb掺杂SnO2形成的电极固溶体是一种导电性好和稳定性高的电极材料。     

SnO2-NiO-IrO2/Ti的制备及电催化氧化甲基橙溶液的研究

因SnO2-NiO特殊的异质结结构,被用作气敏材料和超级电容器电极添加材料,在电催化氧化污水方面研究较少。本文通过添加活性氧化物IrO2提高其导电性来研究SnO2-NiO-IrO2电极电催化甲基橙溶液的效果。热分解法制备不同IrO2含量的Ti/SnO2-NiO-IrO2电极,采用X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、比表面(BET)、循环伏安法(CV)、交流阻抗谱法(EIS)、极化曲线(LSV)、总有机碳(TOC)、紫外可见光谱(UV)、强化寿命等方法系统研究Ti/SnO2-NiO-IrO2电极的电催化性能。结果表明：IrO2改变SnO2晶格中氧空位的浓度,使SnO2晶体结构中产生杂质缺陷,细化晶粒,进而增大复合氧化物涂层的比表面积和导电性,提高活性自由基向内层扩散的速度,从而优化电极的催化活性和稳定性。IrO2掺杂量为23.1%的电极对甲基橙具有最好的降解效果。IrO2掺杂量为23.1%时,电极对甲基橙具有最高降解率为93%,电解反应累加时间最高可达678 h。     

共沉淀法制备金、镍掺杂氧化锌的丙酮气敏性能探究（英文）

利用共沉淀法制备了纯氧化锌和镍掺杂氧化锌。比较了不同Ni掺杂浓度对ZnO丙酮气敏传感器性能的影响。结果表明,1 mol%Ni掺杂ZnO具有最高的丙酮传感性能,其对20μg/g丙酮的响应值达到12。在此基础上,添加金作为异质结进一步激活氧化锌传感材料。实验结果表明,0.03 mol%Au活化1 mol%Ni掺杂的ZnO表现出最高的丙酮气敏响应,对20μg/g丙酮的响应值达到17。同时,该气敏材料保持了对乙醇、甲醛及苯的高选择性,以及对丙酮的快速响应恢复时间(10 s)。     

SnO2掺杂对TiO2压敏电阻器性能的影响

采用固相合成法制备了SnO2掺杂的TiO2基压敏电阻系列样品，并通过XRD和SEM分析，以及Ⅰ-Ⅴ矿曲线测量对材料的结构和电学性能进行了研究。结果表明：SnO2的掺杂抑制了晶粒的生长，晶界相含量增加。电性能测试结果显示，SnO2的掺杂量在0～1．5mo1％内，击穿场强随SnO2掺杂量的增加单调递增；非线性系数先增加后又减小，掺杂量为0．8mol％的样品具有最大的非线性系数（α=8.3）。并对以上的实验结果从理论上给予了分析。     

非均相成核法制备ATO纳米粉末及其性能

Sb掺杂SnO2(Antimonydopedtinoxide,简称ATO)纳米导电粉末具有优良的电学性能,少量的Sb掺杂即可达到抗静电要求,而且不改变基体的性质。采用非均相成核法制备了ATO纳米导电粉末,研究了晶种浓度、反应温度、分散剂对粉末粒径、电阻率等性能的影响;并对其进行了晶粒粒径、物相、微观结构、DTA-TG、表观形貌和能谱分析。结果表明,粉末晶粒粒径为6nm;掺杂Sb没有在SnO2中形成新相;电阻率为0.23?·cm;ATO干凝胶的煅烧过程经历了4个过程;ATO颗粒呈不规则的椭圆状,且分散良好;Sb掺杂均匀性一般。     

Magnetic properties and microstructures of SnO2 doped Mn-Zn ferrites

The effects of additive SnO2 (0.4wt.%), with and without SiO2 (0.02wt.%) and/or CaO(0.04wt.%), on the microstructure and magnetic properties of Mn-Zn ferrites were reported. The results reveal that SnO2 on its own increases the initial permeability ( μi) slightly, but SnO2 with SiO2 and/or CaO decreases the values of μi. However, ferrites with SnO2 additions have reduced power losses. The separate contributions of hysteresis loss and eddy current loss to the total power loss show that SnO2 (with or without SiO2 and/or CaO) doping increases the hysteresis loss slightly, but SnO2 doping alone reduces the eddy current loss significantly (～14%). The additions of SiO2 or CaO further decrease the eddy current loss, and by interaction of SnO2-CaO-SiO2, the eddy current loss is reduced by more thaN20%. These magnetic and microstructural effects were discussed in terms of the additive-impurity interaction, the existence of grain boundary phases, and the effective bulk and grain boundary resistivities of the ferrites.     

Electronic transport properties of Ni-doped CoSb<Subscript>3</Subscript> prepared by encapsulated induction melting

Ni-doped CoSb₃ skutterudites were prepared by encapsulated induction melting and their thermoelectric and electronic transport properties were investigated. The negative signs of Seebeck and Hal coefficients for all Ni-doped specimens revealed that Ni atoms successfully acted as n-type dopants by substituting Co atoms. The carrier concentration increased as the Ni doping content increased, and the Ni dopants could generate excess electrons. However, the carrier mobility decreased as the doping content increased, which indicates that the electron mean free path was reduced by the impurity scattering. The Seebeck coefficient and the electrical resistivity decreased as the carrier concentration increased, as the increase in carrier concentration by doping overcame the decrease in the carrier mobility by impurity scattering. The Seebeck coefficient showed a negative value at all temperatures examined and increased as the temperature increased. The temperature dependence of electrical resistivity suggested that Co_1−xNi_xSb₃ is a highly degenerate semiconducting material. Thermal conductivity was considerably reduced by Ni doping, and the lattice contribution was dominant in the Ni-doped CoSb₃.     

New insights into the accelerated sintering of tungsten with trace nickel addition

In Ni-doped W alloys, 1–4 wt% of Ni was often employed to accelerate densification in conventional sintering process but at the expense of restricted service temperatures because of formation of liquid phase. To break the dilemma, in this work 0.1 wt% Ni was alloyed into W matrix and achieved 98% relative density. The densification and grain growth behaviors of both pure and nickel doped tungsten compacts were investigated, in which a potential new accelerated sintering mechanism by solid-solution alloying was explored. First-principles calculations demonstrated the transition barrier for vacancies in W system was lowered by 34% upon Ni doping. This alloying process therefore was beneficial for lattice diffusion of tungsten that, in turn, improved the sintering performance and service abilities of tungsten-nickel alloy.     

基于SnO2中空纳米球的低温氢气传感器的研究

采用水热法一步合成SnO2纳米材料,采用XRD、SEM、TEM和氮吸附-脱附对材料的结构和形貌进行表征。表征结果表明所制备SnO2纳米材料是由直径150~200 nm的中空纳米球组成,且具有较大比表面积(82.6 m2/g)。采用丝网印刷技术将SnO2气敏浆料涂覆到叉指电极上,制成厚膜型气体传感器器件,研究其对氢气的气敏性能。结果表明SnO2中空纳米球在较低温度(200℃)下对5~200μl/L氢气具有较高的响应值及较快的响应速度,这归因于所制备的SnO2材料的中空结构和较大比表面积,利于氢气气体的吸附与扩散。     

SnO2/Ni复合锂离子电池负极材料的制备及其电化学性能

采用机械球磨法将纳米SnO2和Ni粉末复合,作为锂离子电池负极材料。采用XRD、SEM、TEM和EDS分析球磨过程中材料结构和形貌的变化。对SnO2/Ni复合负极材料的首次库仑效率、循环稳定性及CV曲线等进行测试分析。结果表明:将复合粉末球磨适当时间后,SnO2和Ni可形成结合充分、颗粒尺寸细小、分布均匀的复合材料;SnO2和Ni的复合可有效提高SnO2的首次库仑效率和循环稳定性;SnO2/Ni复合负极材料的循环稳定性随球磨时间的延长而增加,但电极的首次库仑效率随球磨时间的延长呈先增加后下降的趋势;Ni的引入有效减小了SnO2在首次充放电循环过程中生成Li2O的不可逆反应程度,并在随后的循环过程中部分以Li-O化合物的形式进行可逆反应。     

Structural stability, electronic and optical properties of Ni-doped 3C-SiC by first principles calculation

Structural stability along with the electronic and the optical properties of intrinsic 3C-SiC and Ni-doped 3C-SiC were studied by the first principles calculation. For the Ni-doped 3C-SiC, substitution of Ni in Si sub-lattice is energetically more favorable than that in C sub-lattice. Some new impurity energy levels appear in the band gap of Ni-doped 3C-SiC, which can improve the conductivity of 3C-SiC. The imaginary part of the dielectric function of Ni-doped 3C-SiC has three remarkable peaks at 0.69 eV, 2.35 eV, and 4.16 eV. This reveals that doping with Ni can improve the photo-absorption efficiency of 3C-SiC. In the absorption spectrum of Ni-doped 3C-SiC, the absorption edge red-shifts towards the far-infrared region. Furthermore, three new absorbing peaks emerge in the near-infrared region, visible region, and middle-ultraviolet region. These features confer Ni-doped 3C-SiC qualifications of a promising optical material.     

掺铝ZnO纳米粉的制备与气敏特性研究

用可溶性无机盐法(ISG法)制备掺杂Al^3 的ZnO纳米气敏材料，用D／Max0-rB型X-射线粉末衍射仪研究纳米晶的结构。结果表明制备的掺铝ZnO纳米材料属于六方晶系，纤锌矿结构。用Seherrer公式计算得ZnO和掺铝ZnO的平均晶粒分别为40nm和35nm。用掺铝的ZnO纳米粉做成气敏元件，测试了不同铝含量的纳米材料在不同浓度的乙醇气体和氢气下的敏感特性。结果表明随着气体浓度的增加，灵敏度逐渐上升；随着Al含量的减少，材料气敏灵敏性逐渐增强。当铝含量为Al／ZnO=O．5％(mol)时，对O．2％的乙醇气体的灵敏度最大可达到127。并讨论了纳米材料对敏感气体的物理吸附和化学吸附以及纳米氧化物的气敏机理。     

La掺杂的SnO2-Sb中间层对钛基IrO2+Ta2O5电极性能的影响

目的改善Ti/IrO_2+Ta_2O_5涂层电极的析氧电催化性能。方法用热分解法在钛基材上制备了La掺杂的SnO_2-Sb中间层,并以此作为基体涂覆IrO_2+Ta_2O_5活性层,制备了Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5涂层电极。采用扫描电子显微镜(SEM)、能量散射能谱(EDS)及X-射线衍射光谱(XRD)技术分别分析了中间层和活性层的表面形貌、元素组成及晶相结构。采用线性扫描伏安曲线(LSV)和强化寿命测试方法在硫酸溶液中分别研究了Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5涂层电极的析氧电催化活性和使用稳定性。同时,考察了La的掺杂比例对Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5电极强化寿命的影响。结果相对未掺杂La的中间层,掺杂La后的中间层表面裂纹减少,有更高的析氧过电位和更低的析氧电流密度。La掺杂对活性层的表面形貌和晶相结构基本没有影响,但电极的析氧电流密度有所提高。通过测试不同La掺杂比例涂层电极的强化寿命,发现La最佳掺杂比例为nLa:nSn=0.5:100。和未掺杂La涂层相比,La最佳掺杂比例涂层电极的强化寿命提高了22.8%。结论相对于未掺杂的Ti/SnO_2-Sb/IrO_2+Ta_2O_5电极,La掺杂后的Ti/SnO_2-Sb-La/IrO_2+Ta_2O_5涂层电极析氧电催化活性和强化寿命都得到改善。