Synthesis and characterization of yttrium and antimony codoped SnO₂ conductive nanoparticles

Y was used as a dopant in preparing conductive powder to improve its performance. Y and Sb co-doped SnO2 conductive nanoparticles were prepared by the complexation-coprecipitation method with Sn,Sb2O3 and Y2O3 as the raw materials. Crystal phase,thermal behavior and structure of the prepared conductive nanoparticles were characterized by X-ray diffraction(XRD) ,thermal analysis(TG-DSC) ,Fourier transform infrared(FTIR) and transmission electron microscopy(TEM) techniques,respectively. The Y and Sb co-doped SnO2 conductive nanoparticles with a structure of tetragonal rutile had intense absorption in 4000-2500 cm-1,and the diameter ranged from 10 to 30 nm. The resistivity of Y and Sb co-doped SnO2 conductive nanoparticles was as low as 0.09 Ω·cm which was 4.6 times lower than that of Sb doped SnO2 conductive nanoparticles.     

粒径可控纳米金的制备及表征

以氯金酸(HAuC l4)和硼氢化钠(NaBH4)为原料,柠檬酸钠(Na3C6H5O7)作保护剂,在室温条件下,一步还原制备出了不同粒径的单分散纳米金颗粒。应用X射线衍射仪、透射电子显微镜、激光粒度分布仪和紫外-可见分光光度计对产品进行表征,结果表明,制备的纳米金颗粒呈球形,为面心立方结构;柠檬酸钠保护剂的存在,不但提高了金颗粒的单分散性和稳定性,还在一定程度上抑制了金颗粒的生长,使得其粒径可控,且分布很窄。紫外-可见吸收光谱反映出,随着粒径的增大,胶体金在可见光区的最大吸收峰逐渐向长波方向移动。     

Synthesis and photocatalytic property of Ce-doped SnO2

Pure SnO₂ and Ce-doped (1%, 4%, 7%, 10% in mass ratio) SnO₂ powders were prepared by a simple sol-gel method. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) specific surface area analyzers. Results showed that the 7% Ce-doped sample has a particle size of 0.1-0.3 μm with a narrow particle size distribution while the pure SnO₂ was consisted of large agglomerated particles with a diameter up to several micrometers. When used as the catalyst to degrade methyl orange (MO), the 7% Ce-doped sample showed best photocatalytic property. These properties can be attributed to the large surface area and small particle size of the 7% Ce-doped sample.     

Synthesis and characterization of the structural and electrochemical properties of Nd-Al codoped amorphous nickel hydroxide

Nd-Al codoped amorphous nickel hydroxide powders were synthesized by microemulsion precipitation method combined with rapid freezing technique.The microstructure of the prepared samples was analyzed with X-ray diffractometer(XRD),scanning electron microscopy(SEM),and Raman spectroscopy.The electrochemical performances of the prepared samples were characterized with charge/discharge test,cyclic voltammetry,and electrochemical impedance spectra.The results showed that the codoping of Nd-Al resulted in more st...     

Synthesis and characterization of branched yttrium hydroxide fluoride microcrystals with hierarchical tubular structure

Hexagonal yttrium hydroxide fluoride microcrystals were prepared by a two-step hydrothermal route using yttrium nitrate, sodium hydroxide and sodium fluoride as raw materials to react in propanetriol solvent. The samples were characterized by powder X-ray diffraction (XRD), energy dispersive spectrum (EDS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier trans-form infrared spectroscopy (FT-IR), thermogravimetre and differential-thermogravimetric analysis (TG-DTA), which revealed that Y(OH)2.14F0.86 microcrystals were multi-branched and that the branches of Y(OH)2.14F0.86 microcrystals were composed of hierarchical tubes. This novel multi-branched and intriguing hierarchical tubular structure of yttrium hydroxide fluoride maybe has a potential application in photoelectric crystals. The formation of branched Y(OH)2.14F0.86 microcrystals with hierarchical tubular structure were due to the substitution reaction and Oswald ripening.     

Fe3O4纳米粒子的合成与表征

以P123胶束作为"纳米反应器",采用水溶液法合成了Fe3O4纳米粒子.采用场发射扫描电子显微镜(FE-SEM)、X射线衍射仪(XRD)、傅立叶变换红外光谱(FTIR)和样品振动磁强计等现代化分析测试手段对产物的形貌、结构和磁性进行了测试表征.结果表明,合成的Fe3O4纳米粒子粒径大小在30～120 nm可控,它们在常温下是超顺磁性的且具有较高的饱和磁化强度.所合成的纳米铁氧体磁性材料在信息存储、生物医药和催化等领域具有重要的理论研究价值和广阔的应用前景.     

Nd-doped SnO2: characterization and its gas sensing property

Nd-doped (2%, 5%, 10% in mass ratio) SnO₂ powders were prepared via a facile hydrothermal procedure. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) specific surface area analyzers. Results showed that the Nd-doped SnO₂ samples had more uniform and smaller primary particles compared with the pure sample, the particle size of the doped SnO₂ decreased gradually with the increase of Nd, and the specific surface area also increased with the increase of the doped Nd. When used as gas sensing materials, the 5% and 10% Nd-doped sample showed high sensitivity and selectivity to ethanol. Furthermore, the Nd-doped sample showed fast response and recovery time to ethanol gas. This could be attributed to their small diameter, large surface area and Nd element doping.     

Synthesis of yttrium and cerium doped ZnO nanoparticles as highly inexpensive and stable photocatalysts for hydrogen evolution

Yttrium and cerium co-doped ZnO nanoparticles were synthesized by combustion route and characterized using X-ray diffraction(XRD),scanning electron microscopy(SEM),Brunauer-Emmett-Teller(BET),energy dispersive spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS),UV-visible diffuse reflectance spectroscopy(UV-vis DRS),photoluminescence(PL)and electrochemical impedance spectroscopy(EIS)techniques.The introduction of yttrium ions has efficiently increased the relative percentage of Ce³⁺ions in ZnO.Yttrium and cerium co-doped ZnO shows efficient photo activity for hydrogen evolution(10.61 mmol/((g·h))higher than previously reported optimal value for rare earth codoped ZnO photocatalysts.This remarkably increased hydrogen evolution can be ascribed to the synergy between electronic anchoring effect of Y³⁺/Y²⁺and Ce⁴⁺/Ce³⁺redox couples.This report presents new idea for the synthesis of efficient photocatalyst using economical route and ion anchoring effect.The hydrogen evolution was also tested using Na₂S and Na₂SO₃as electron donors under visible light illumination.The synthesized photocatalysts also exhibit high stability.     

透明导电材料Cd_2SnO_4的制备Ⅱ—热压烧结

将2:1摩尔比的CdO与SnO_2混合粉体进行原位热压烧结,制备Cd_2SnO_4。采用XRD衍射仪、四探针电阻测试仪和扫描电镜,分析热压气氛,Sb掺杂元素以及热处理工艺对Cd_2SnO_4靶材的物相结构和导电性能的影响。结果表明:900℃原位热压烧结时,由于温度低,扩散反应发生不完全,生成部分Cd_2SnO_4化合物,少量Cd和Sn元素仍以氧化物的形式存在,未出现第二相CdSnO_3;氩气烧结比真空烧结更有利于扩散和化合反应发生;掺杂1%(质量分数)Sb元素的靶材电阻率降低至0.5×10~(-3)Ω·cm。高温退火热处理时扩散反应得以继续,靶材中Cd_2SnO_4含量有明显增加。为了克服原位热压温度和保温时间的限制所引起的化合反应不完全,优化热压工艺如下:采用单相Cd_2SnO_4复合粉体为原料,热压温度为1050℃,保温时间2小时,所得靶材均匀且晶粒细小,致密度达到92%,电阻率低至3×10~(-4)Ω·cm,第二相CdSnO_3含量低于2%,满足了镀膜用Cd_2SnO_4靶材的性能要求。     

Synthesis and characterization of Co_(1-2x)Ni_xMn_xCe_yFe_(2-y)O_4 nanoparticles

Spinel ferrite Co_(1-2 x)Ni_xMn_xFe_(2-y)Ce_yO_4(0.0≤x=y≤0.3) nanoparticles(NPs) were prepared by sol-gel auto-combustion method.The synthesized NPs were examined using several techniques such as X-ray diffraction(XRD),field emission scanning electron microscopy(FE-SEM) coupled with EDX and elemental mapping,transmission electron microscopy(TEM),Fourier-transform infrared spectroscopy(FT-IR),and a vibrating sample magnetometer(VSM).The analysis of the crystal structure and the phase identification of samples indicates the formation of spinel cubic phase with the occurrence of CeO_2 as secondary phase when the content of Ce substitution element increases.In addition,all produced samples exhibit cubic symmetry with space group Fd3m.TEM confirms the presence of two phases,i.e.,the cubic spinel ferrite and the cubic cerium oxide(CeO_2).The characteristics of hysteresis loops reveal the soft ferrimagnetic nature of the different synthesized samples.The saturation(M_s) and remanent(M_r) magnetizations fall on increasing the content of substituting elements.Compared with pure CoFe_2O_4 NPs,the value of coercive field(H_c) slightly increases for x=y=0.1 and x=y=0,2 NPs.Then,H_c reduces with further increasing the x and y contents.The squareness ratio is found to be in the 0.528-0.400 interval,indicating the single domain NPs with uniaxial anisotropy for the different produced NPs.The magneto crystalline anisotropy constant(K_(eff)),anisotropy field(H_a),magneton number(n_B) and the demagnetizing field(N) were also determined and discussed.     

Synthesis and characterization of Sb-doped SnO2-(CeO2-TiO2) composite thin films deposited on glass substrates for antistatic electricity and UV-shielding

Sb-doped SnO₂ (ATO)-(CeO₂-TiO₂) thin Films were deposited on glass substrates using the mixed solution including CeO₂-TiO₂ precursor and ATO particles by sol-gel dip coating process. ATO particles were prepared using low-temperature hydrothermal process. The mixed molar ratio of ATO to (CeO₂-TiO₂) vs the properties of CeO₂-TiO₂ thin film was investigated. The optical properties of the films were characterized by UV-visible transmission and infrared reflection spectra, the sheet resistance of ATO particles and films were measured by rubber sheeter (MYI-50) and four-point probe (HisuperGroup Inc, SDY-5), the surface morphology and structure of the films were analyzed using 3D Digitale Mikroskop and X-ray diffraction (XRD), respectively. The results showed that the ATO precursor solution lost weight completely at about 500 °C, and the ATO particles was obtained, which indicated the same rutile lattice structure as SnO₂. The glass substrates coated with ATO-(CeO₂-TiO₂) thin films showed better properties in antistatic electricity (10⁴-10⁶ Ω/?), shielding UV (almost 100%), visible light transmission (70%) and infrared reflection (>30%).     

Preparation and characterization of NiFe2O4 nanoparticles

Ni-Ferrite (NiFe₂O₄) nanoparticles haves been synthesized by simple and low cost co-precipitation technique. The synthesized product was characterized by X-ray diffraction (XRD), High resolution scanning electron microscopy (HRSEM) and vibrating sample magnetometry (VSM). The XRD and HRSEM results showed that the average particle size of the synthesized product was 20–25 nm with inverse spinel structure. The morphology of as synthesized product was in spherical shape. The existence of ferromagnetic properties was confirmed by VSM.     

Complexation-Coprecipitation Synthesis and Characterization of Neodymium and Antimony Doped SnO2 Conductive Nanoparticles

Nd and Sb doped SnO2 conductive nanoparticles were prepared by the complexation-coprecipitation method with Sn, Sb2O3 and Nd2O3 as the raw materials. Thermal behavior, crystal phase, and structure of the prepared conductive nanoparticles were characterized by TG/DSC/DTG, FTIR, XRD and TEM techniques, respectively. The resistivity of the prepared conductive nanoparticles was 0.12 Ω·cm. TG/DSC/DTG curves show that the precursors lose weight completely before 750 ℃. FTIR spectrum shows that the vibration peaks are wide peaks in 731～617 cm-1, and the Nd and Sb doped SnO2 conductive nanoparticles have intense absorption in 4000～2000 cm-1. Nd and Sb doped SnO2 have a structure of tetragonal rutile, and complex doping is achieved well by complexation-coprecipitation method and is recognized as replacement doping or caulking doping. TME shows that the particles are weakly agglomerated, and the size of the particles calcined at 1000 ℃ ranges about 10 nm to 30 nm.     

Complexation-Coprecipitation Synthesis and Characterization of Erbium and Antimony Doped SnO2 Conductive Nanoparticles

Er was used as a dopant for the first time in preparing conductive powder to improve its performance. Er and Sb doped SnO₂ conductive nanoparticles were prepared by the complexation-coprecipitation method with Sn, Sb₂O₃ and Er₂O₃ as the raw materials. Thermal behavior, crystal phase, and structure of the prepared conductive nanoparticles were characterized by TG/DSC, FTIR, XRD and TEM techniques, respectively. The resistivity of the prepared conductive nanoparticles was 0.29 Ω·cm; TG/DSC curves showed that the precursors lost weight completely before 750 °C; FTIR spectrum showed that the vibration peak were wide peak in 711 × 600 cm⁻¹; the Er and Sb doped SnO₂ conductive nanoparticles had intense absorption in 4000 × 1600 cm⁻¹; Er and Sb doped SnO₂ had a structure of tetragonal rutile; complex doping was achieved well by complexation-coprecipitation method and was recognized as replacement doping or caulking doping; TME showed that the particles were weakly agglomerated, the size of the particles calcined at 800 °C ranged approximately from 10 to 30 nm.     

Synthesis and characterization of Gd-doped PbMoO_4 nanoparticles used for UV-light-driven photocatalysis

Gd-doped PbMoO_4 nanoparticles were prepared by a refluxing method at 80℃ for 2 h.Effect of molar content of Gd dopant on phase,morphology and optical properties was studied.The as-prepared Gddoped PbMoO_4 samples can be indexed to pure tetragonal PbMoO_4 phase.The particles size of PbMoO_4 is decreased with increasing in the molar content of Gd dopant from 15.20±3.04 nm for pure PbMoO_4 to 8.72±1.53 nm for 5 mol% Gd-doped PbMoO_4.The absorption of 5 mol% Gd-doped PbMoO_4 nanoparticles shows red-shift caused by lattice distortion of PbMoO_4.The photocatalytic performance of 5 mol% Gddoped PbMoO_4 nanoparticles shows the highest degradation of rhodamine B(RhB) of 97.92% under UV radiation and 67.65% under visible radiation because Gd~(3+) dopant as an electron acceptor plays the role in enhancing the separation of electron-hole pair.     

Ti/SnO2-Sb:Eu3+电极制备及性能表征

以SnCl4·5H2O、Sb2O3和Eu2O3为原料,以钛片为基体,采用涂层热解法制备了Eu3+掺杂Ti/SnO2-Sb电极.研究了电极的电化学性能,对所制备的电极作LSV和Tafel曲线,以对硝基苯酚为目标降解有机物,考察了电极的电催化活性.分析Eu3+掺杂量对电极性能的影响,采用X-射线衍射(XRD)、扫描电镜(SEM)和能谱仪(EDS)等检测方法对Eu3+掺杂Ti/SnO2-Sb电极表面涂层的晶体结构、形貌和元素组成进行了研究;,发现掺杂量为1％的电极的性能最佳,此条件下得到的电极有高的析氧电位和电催化活性,以及较好的电极涂层结构和覆盖度.     

透明导电材料Cd_2SnO_4的制备Ⅰ-固相烧结制备原料粉体

将不同配比的Cd O与Sn O2原料粉体充分混合后在750℃,850℃,950℃,1050℃,1150℃温度下进行无压烧结。采用XRD衍射仪和四探针电阻测试仪分析原料配比与烧结温度对无压烧结Cd2Sn O4靶材结构演化和电阻率的影响。结果表明:750~850℃低温无压烧结时,扩散反应发生缓慢,只有少量的Cd2Sn O4生成,大部分Cd和Sn元素以氧化物的形式存在。950~1050℃无压烧结,随着温度升高,扩散反应速率较快,发生大量合成反应生成Cd2Sn O4,当Sn O2过量时,Cd O完全参加反应。当温度上升至1150℃时,Cd2Sn O4含量大幅度增加,伴随出现第二相Cd Sn O3。四探针测试结果显示:随着温度的升高,Cd2Sn O4主相含量增加,靶材电阻率逐渐降低至19.9×10-3Ω·cm。根据无压烧结实验的固相演化规律,采用2∶1化学计量比的Cd O与Sn O2粉体为原料,充分混合后在1000℃下煅烧2~3小时,可得到均匀单相亮黄色Cd2Sn O4原料粉体。     

制备SiO_2包覆的Fe_3O_4磁性纳米复合粒子

首先用化学共沉淀法制备出柠檬酸三铵改性的Fe3O4磁性纳米粒子,然后用反相微乳液法制备了SiO2包覆的Fe3O4磁性纳米复合粒子。用X射线衍射仪(XRD),透射电子显微镜(TEM),傅立叶-红外光谱仪(FTIR)和振动样品磁强计(VSM)表征SiO2包覆的Fe3O4磁性纳米复合粒子。结果表明,SiO2成功包覆在Fe3O4表面,且饱和磁化强度下降,但矫顽力趋近于零,仍显示超顺磁性。