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1.
为了提高NiO气敏材料的响应和恢复速度,采用磁场诱导肼还原法和高温氧化法制备Zn掺杂NiO纳米线,研究Zn掺NiO纳米线基传感器对于氨气的敏感性能。结果表明:随着Zn掺杂浓度的提高(摩尔分数2%~5%),XRD衍射峰向小角度偏移0.2°~0.4°, 且晶面间距增大0.01~0.02 nm,均说明锌离子已成功掺入到NiO晶格中;与未掺杂的NiO纳米线传感器相比,掺杂Zn的NiO纳米线传感器的响应速度提升了6~8倍,恢复速度提升了108~120倍;掺杂的NiO基气敏传感器同时拥有着优异的稳定性和选择性。
相似文献
2.
《郑州大学学报(工学版)》2016,(2)
为改善Zn O对丙酮的气敏响应,采用静电纺丝法,利用PVP/Zn(NO_3)·6H_2O/Y(NO_3)_3·6H_2O等制成的前驱液,制备了钇掺杂的Zn O纳米纤维,通过XRD、SEM等表征手段对制备的纯Zn O和掺杂的Zn O样品进行了表征分析.将制备的纯Zn O和钇掺杂的Zn O纳米纤维制成电阻型气体传感器.气敏测试结果表明,Y掺杂有效改善了Zn O纳米纤维对丙酮气体的敏感特性.在440℃时,对1×10~(-6)~200×10~(-6)(体积分数)丙酮具有良好的响应,响应时间为14~40 s,恢复时间为20~55 s,对于100×10~(-6)丙酮的响应值约为70(S=Ra/Rg),并且对于乙醇、氨气、甲醇、甲醛、甲苯、苯有较好的选择性.同时分析了该材料对丙酮的敏感机理. 相似文献
3.
以木质素磺酸钠为碳源和硫源,低共熔溶剂(DES)为氮源和反应溶剂制备了一种氮、硫双掺杂的碳量子点(N,S-CQDs)。制备的N,S-CQDs的粒径分布均匀,平均粒径为4.95 nm,量子产率达到了35.7%,量子产率大幅提升。制备的N,S-CQDs对Fe3+具有优异的敏感性,可用于Fe3+的定量检测,检测限为0.25μmol·L-1,检测范围是0~200μmol·L-1。 相似文献
4.
为探究Fe2+掺杂对十二胺分子(DDA)及其阳离子(DDA+)在高岭石层面吸附的微观影响机制,对DDA和DDA+在Fe2+掺杂高岭石(001)及(■)面的吸附进行了密度泛函理论(DFT)计算.结果表明:DDA和DDA+在Fe2+掺杂高岭石层面的吸附机理为氢键和范德华静电引力共同作用.DDA在Fe2+掺杂高岭石层面吸附以氢键作用为主,范德华静电引力作用为辅;DDA+在Fe2+掺杂高岭石层面吸附以范德华静电引力作用为主,氢键作用为辅.Fe2+的杂质缺陷增强了高岭石(001)面的表面活性,对(■)面的表面活性影响较小.研究结果可为进一步研究煤泥水中黏土颗粒表面的真实吸附状态及煤泥水高效处理药剂的设计提供理论依据. 相似文献
5.
以Cr3+和Bi3+为掺杂剂,按照镓酸锌Zn0.97Ga2O3.97(ZGO)化学计量比,采用双相水热法制备了ZGO:Cr3+,Bi3+红色无机荧光粉,并通过透射电子显微镜、分光光度法和荧光光谱法分析了荧光粉样品的微观形态、晶体结构和发光性能。实验结果表明:Cr3+和Bi3+的最佳摩尔掺杂率分别是1%和2%,荧光粉最佳掺杂浓度化学式为ZGO:0.01Cr3+,0.02Bi3+,所得荧光粉颗粒为组分均匀的类球形颗粒,平均粒径为8 nm。在近紫外光的激发下,相对于单掺杂荧光粉ZGO:0.01Cr3+,双掺杂荧光粉ZGO:0.01Cr3+,0.02Bi3+在漫反射光谱中<350、350~470和470~650 nm的吸收带强度明显增强。此外,在激发和发射光谱中,ZGO:0.01Cr3+,0.02Bi3+的发射强度为ZGO:0.01Cr3+的2.5倍,表明该荧光粉的发光性能得到显著提升。 相似文献
6.
通过溶剂热方法大量得到具有二维片状结构的前驱物后,再经煅烧处理成功制备出了多孔ZnO纳米片.用XRD、FESEM、TEM等手段对材料的结构和形貌进行了表征,并系统研究了材料的气敏性能.结果表明,多孔ZnO纳米片为单晶结构,制备的气敏元件对丙酮气体具有较高的灵敏度和选择性.制备出的多孔ZnO纳米片是制备丙酮传感器的理想材料,所制备的气敏元件具有良好的响应恢复特性. 相似文献
7.
通过自牺牲模板法制备Y掺杂ZnO的半导体材料(Zn-MOF-Y),并对合成材料进行表征。Zn-MOF-Y的微观特征表现为由纳米颗粒组成的纳米球为ZnO和YF3的复合材料,含有Zn、O、Y、F这4种元素,其比表面积为15.784 4 m2/g,平均孔径为15 nm。对以Zn-MOF-Y为传感材料制备的半导体气体传感器进行气敏测试,其对100 mg/L的NO2的响应值为20,传感器的响应与浓度呈现线性关系;对100 mg/L的NO2的响应/恢复时间为82/64 s,并且该传感器具有优良的稳定性。由于该传感器具有以上优点,这为其以后的实际应用提供了可能。 相似文献
8.
以兴安杜鹃(Rhododendron dauricum L.)花为碳源,采用一步水热法合成了蓝色荧光水溶性兴安杜鹃花碳点(Rhododendron carbon dots, R -CDs),并通过紫外-可见吸收光谱(UV -vis)、荧光发射光谱(FL)和傅里叶变换-红外光谱(FT -IR)等对其进行了表征.表征显示:合成的R -CDs表面存在氨基、羟基、羰基等官能团; 最大激发波长和发射波长分别为335 nm和414 nm,具有典型的激发波长依赖性; R -CDs的荧光可被Fe3+离子有效猝灭,同时可对Fe3+离子实现“裸眼”识别.基于R -CDs与Fe3+离子的显色反应特性,制备了一种用于快速检测水中Fe3+离子的试纸,测试结果显示该试纸对Fe3+离子的检测范围为0.5~10 mmol/L,检出限为2.5 nmol,因此本文方法制备的Fe3+离子试纸具有较好的应用前景. 相似文献
9.
为了实现水溶液中Fe3+和Hg2+的快速简捷检测,以柠檬酸和硫脲为前驱体,采用一步水热法合成硫、氮共掺杂碳量子点荧光探针。通过透射电镜、傅里叶红外光谱、X射线光电子能谱、荧光分光光度计和紫外-可见吸收光谱分析合成碳点的形貌特征及荧光性能。结果表明:N—S—CDs的平均粒径为8 nm,分布均匀;表面富有各种官能团,具有良好的水溶性;在紫外灯照射下发出强烈的蓝色荧光,荧光量子产率高达36.8%;随激发波长增大,N—S—CDs发射峰荧光强度先增大后减小,在440 nm处荧光强度达到最高,并且其发射峰随着激发波长发生明显红移。N—S—CDs对Fe3+和Hg 2+具有较高选择性;Fe3+浓度在40~130μmol/L,Hg 2+浓度40~80μmol/L,荧光强度与2种离子呈良好线性关系,线性回归方程分别为F0/F=0.021 32c_(Fe3+)+0.349 45和F0/F=0.186 11c_(H... 相似文献
10.
以CoOCl2·6H2O为钴源,NaOH为沉降剂,通过水热法制备出Co3O4纳米粉末,并以Co3O4纳米粉末为敏感材料制作了旁热式气敏元件。X射线衍射和透射电子显微镜表征显示Co3O4纳米粉晶粒平均粒径15.6 nm。气敏测试结果表明元件在80 ℃、臭氧质量浓度为4.280×10-8 g/mL的条件下,对2.009×10-7 g/mL乙醇的灵敏度达到29,而空气中时元件对乙醇的灵敏度仅为4,O3的加入提高了Co3O4气敏元件在80 ℃的灵敏度,并将对乙醇气敏的最佳工作温度由100 ℃降低至80 ℃,实现了Co3O4在低温下(80 ℃)的气敏性能检测。 相似文献
11.
LiCo1/3Ni1/3Mn1/3O2 was coated by a layer of 1.0 wt% CeO2 via sol-gel method. The bared and coated LiMn1/3Co1/3Ni1/3O2 was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammogram (CV) and galvanotactic
charge-discharge test. The results show that the coating layer has no effect on the crystal structure, only coating on the
surface; the 1.0 wt% CeO2-coated LiCo1/3Ni1/3Mn1/3O2 exhibits better discharge capacity and cycling performance than the bared LiCo1/3Ni1/3Mn1/3O2. The discharge capacity of 1.0 wt% CeO2-coated cathode is 182.5 mAh·g−1 at a current density of 20 mA·g−1, in contrast to 165.8 mAh·g−1of the bared sample. The discharge capacity retention of 1.0 wt% CeO2-coated sample after 12 cycles reaches 93.2%, in comparison with 86.6% of the bared sample. CV results show that the CeO2 coating could suppress phase transitions and prevent the surface of cathode material from direct contact with the electrolyte,
thus enhance the electrochemical performance of the coated material. 相似文献
12.
Guo Hua-jun Li Xin-hai Zhang Xin-ming Zeng Su-ming Wang Zhi-xing Peng Wen-jie 《中南工业大学学报(英文版)》2005,12(1):44-49
LiNi0.45Co0.10Mn0.45O2 was synthesized from Li2CO3 and a triple oxide of nickel, cobalt and manganese at 950 °C in air. The structures and characteristics of LiNi0.45Co0.10Mn0.45O2, LiCoO2 and LiMn2O4 were investigated by XRD, SEM and electrochemical measurements. The results show that LiNi0.45Co0.10Mn0.45O2 has a layered structure with hexagonal lattice. The commercial LiCoO2 has sphere-like appearance and smooth surfaces, while the LiMn2O4 and LiNi0.45Co0.10Mn0.45O2 consist of cornered and uneven particles. LiNi0.45Co0.10Mn0.45O2 has a large discharge capacity of 140.9 mA · h/g in practical lithium ion battery, which is 33.4% and 2.8% above that of
LiMn2O4 and LiCoO2, respectively. LiCoO2 and LiMn2O4 have higher discharge voltage and better rate-capability than LiNi0.45Co0.10Mn0.45O2. All the three cathodes have excellent cycling performance with capacity retention of above 89.3% at the 250th cycle. Batteries
with LiMn2O4 or LiNi0.45Co0.10Mn0.45O2 cathodes show better safety performance under abusive conditions than those with LiCoO2 cathodes.
Foundation item: Project(50302016) supported by the National Natural Science Foundation of China; Project(2005037698) supported by the Postdoctoral
Science Foundation of China 相似文献
13.
Yuhong Chen Zhiyuan Tang Guoqing Zhang Xuemei Zhang Ruizhen Chen Yuangang Liu Qiang Liu 《武汉理工大学学报(材料科学英文版)》2009,24(3):347-353
Mg3(PO4)2-coated Li1.05Ni1/3Mn1/3Co1/3O2 cathode materials were synthesized via co-precipitation method. The morphology, structure, electrochemical performance and
thermal stability were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry(CV),
electrochemical impedance spectroscopy(EIS), charge/discharge cycling and differential scanning calorimeter (DSC). SEM analysis
shows that Mg3(PO4)2-coating changes the morphologies of their particles and increases the grains size. XRD and CV results show that Mg3(PO4)2-coating powder is homogeneous and has better layered structure than the bare one. Mg3(PO4)2-coating improved high rate discharge capacity and cycle-life performance. The reason why the cycling performance of Mg3(PO4)2-coated sample at 55 °C was better than that of room temperature was the increasing of lithium-ion diffusion rate and charge
transfer rate with temperature rising. Mg3(PO4)2-coating improved the cathode thermal stability, and the result was consistent with thermal abuse tests using Li-ion cells:
the Mg3(PO4)2 coated Li1.05Ni1/3Mn1/3Co1/3O2 cathode did not exhibit thermal runaway with smoke and explosion, in contrast to the cells containing the bare Li1.05Ni1/3Mn1/3Co1/3O2.
Funded by the National Natural Science Foundation of China (No. 20273047) 相似文献
14.
Baijun Yan Jianhua Liu Yunduo Dai Qifeng Shu Zhihua Ren 《北京科技大学学报(英文版)》2007,14(5):395-398
The molar heat capacities of La2Mo209 and La1.9Sr0.1MO209-δ were obtained using the differential scanning calorimetry (DSC) technique in a temperature range from 298 to 1473 K. The DSC curve of La2Mo209 showed an endothermal peak around 834 K corresponding to a first-order monoclinic-cubic phase transition, and the enthalpy change accompanying this phase transition is 5.99 kJ/mol. No evident endothermal peak existed in the DSC curve of La1.9Sr0.1MO209-δ, but a broad thermal anomaly existed in its heat capacity curve at around 832 K. In addition, the heat capacity values of La2Mo209 and La1.9Sr0.1MO209-δ began to decrease at 1196 and 1330 K, respectively. The non-transitional heat capacity values of La2Mo209 and La1.9Sr0.1MO209-δ were formulated using multiple regression analysis in two temperature ranges. 相似文献
15.
Li(Ni1/3Co1/3Mn1/3)O2的(3b)位有序-无序效应研究
曹春晖1,2, 张建1, 杨传铮1, 夏保佳1
(1.上海微系统与信息技术研究所,上海 200050;
2.中国科学院大学, 北京100049)
创新点说明:
提出了有序度的概念,通过理论模拟了过渡金属在3b位不同有序度下的衍射情况。
研究目的:
借助理论衍射研究镍钴锰在三元材料中的占位情况,为实际得到的衍射数据分析起指导作用。
研究方法和结果:
借助Powercell程序模拟不同结构下的衍射情况。结果表明:对于Li(Ni1/3Co1/3Mn1/3)O2,基体衍射线的强度不随有序度而变化,有序度增加时,超点阵衍射线强度增加,但是即使对于有序度最大时,超点阵线的相对强度只有0.225%和0.043%。
结论:
3b位的有序无序很难通过常规的衍射实验观测到,必须提高X射线源的强度才可能观测到。
关键词:Li(Ni1/3Co1/3Mn1/3)O2, 有序-无序,超结构,衍射
相似文献16.
Luminescent properties of BaO-La2O3-B2O3 glasses with dopant 总被引:4,自引:0,他引:4
The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were stud{ed. The emissions spectra of Eu^2 and Eu^3 were observed in BaO-La2O3-B2O3-Eu2O3 glasses.The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu^2 , the sharp emission peaks at 592, 616, 650 and 250 nm correspond to 5^D0→1Fj(j=1--4) emission transition of Eu^3 ,respectively, which indicates that the BaO-La2O3a-B2O3-Eu2O3 glass can convert ultraviolet and green omponents of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent in--tensity of Eu^2 increases with increasing the molar ratio of Tb^3 in BaO-La2O3-B2O3-Eu2O3a-Tb4O3 glasses, whereas the luminescent intensity of Eua^3 decreases. So the luminescent intensity of Eu(Ⅲ,Ⅱ) is influenced by Tb^3 .These phenomena can be explained by electron transfer mechanism; Eu^3 (4f6) Tb^3 (4f^8)→Eu^2 (4f′) Tb^4 (4f′). Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced. 相似文献
17.
以硝酸铟(In(NO3)3·xH2O)、对苯二甲酸(H2BDC)、六水合硝酸钴(Co(NO3)· 6H2O) 为原料, 首先采用一锅油浴法合成了含有Co2+ 的铟基金属有机框架材料(MOFs) Co2+/CPP-3(In) 材料, 然后在450 ℃ 下焙烧制备Co3O4/In2O3 复合物气敏材料, 将Co3O4/In2O3 复合物的粉体制作成传感器, 并对其气敏性能进行研究。利用扫描电子显微镜和X 射线衍射仪(XRD) 对双金属MOFs Co2+/CPP-3(In) 材料和Co3O4/In2O3 复合物进行表征, 采用静态配气法测试其气敏性能。结果表明, Co3O4/In2O3(nCo : nIn = 0.4 : 1) 样品的形貌保留了其MOFs 前驱体的棒状结构, 棱柱形框架更为突出, 表面呈凹陷状, 棒体中间粗两边细, 六角截面和棒体均布满了孔洞。结合EDX 和XRD
表征结果, Co2+/CPP-3(In) MOFs 前驱体完全转化成Co3O4/In2O3 复合物; Co3O4/In2O3(nCo : nIn = 0.4 : 1) 复合物在
70 ℃ 下对5×10-6 H2S 的气敏性能最优, 响应值达到153, 是同条件下纯备In2O3对H2S 响应值的5 倍, 并且有较好的重复性、选择性和稳定性。 相似文献
18.
采用磷酸银与具有可见光吸收能力的TiO_2基光催化剂相复合的方法,对带有氧空穴的二氧化钛(TiO_2-OV)的复合磷酸银光催化材料的性能进行了研究.采用光处理法成功制备出了具有可见光吸收能力的氧空穴二氧化钛材料,利用化学吸附法成功制备出了磷酸银/氧空穴二氧化钛复合光催化剂.透射电镜结果显示,磷酸银纳米颗粒均匀分散于氧空穴二氧化钛表面,形成结构完美的复合光催化剂;光催化降解罗丹明B实验结果表明,所制备的磷酸银/氧空穴二氧化钛复合光催化剂的光催化活性明显优于磷酸银光催化材料. 相似文献
19.
We have prepared the Ho-substituted bismuth titanate (Bi3.4Ho0.6Ti3O12, BHT) thin films on Pt/Ti/SiO2/Si substrates using sol-gel method. The crystal structure and morphology of the films were characterized using X-ray diffraction
and atomic force microscopy. The BHT film shows a single phase of Bi-layered Aurivillius structure and dense microstructure.
The 2Pr and 2Ec of the 600-nm-thick BHT film were 38.4 μC/cm2 and 376.1 kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about
310 and 0.015 at a frequency of 1 MHz, respectively. The Pr value decreased to 93% of its pre-fatigue values after 4.46×109 switching cycles at 1 MHz frenquency, and the BHT film shows good insulating behavior according to the test of leakage current.
Supported by the Hubei Province Natural Science Foundation (Grant No. 2007ABA309) 相似文献
20.
为明晰Li Mn1.5Ni0.5O4正极材料的动力学性能,采用水热辅助共沉淀法合成了尖晶石Li Mn1.5Ni0.5O4正极材料,并采用扫描电镜(SEM)、X射线粉末衍射(XRD)和电化学阻抗(EIS)研究了材料的结构和锂离子嵌脱动力学.实验结果表明:共沉淀法制备的Li Ni0.5Mn1.5O4材料颗粒呈均匀球形,且平均粒径较小,粒度分布较窄.在循环过程中,Li Ni0.5Mn1.5O4的电荷转移电阻增大,锂离子扩散系数减小,进而电子电导率和离子电导率下降.温度升高后,Li Ni0.5Mn1.5O4材料的溶液电阻变化不大,但是电荷转移电阻逐渐增大,锂离子扩散系数逐渐减小;此外,随着温度的升高,Li Ni0.5Mn1.5O4材料的溶解速度加快,从而导致SEI膜的厚度增大.Li Ni0.5Mn1.5O4材料的嵌脱锂动力学与温度和循环次数有密切关系. 相似文献