用于超级电容器的纳米氧化镍/石墨薄片/银复合电极材料的超声法合成及性能

通过简单超声法制备了球状NiO纳米颗粒、NiO/石墨薄片(NiO/GNS)和NiO/GNS/Ag纳米复合材料。在NiO/GNS和NiO/GNS/Ag复合材料中,GNS作为NiO和Ag纳米颗粒分散的模板,不仅有效避免了NiO和Ag纳米颗粒的团聚,还改善了复合材料的电化学性能。采用场发射扫描电子显微镜(SEM)、透射电子显微镜(TEM)和X射线衍射对样品的成分、形貌和结构进行了表征。NiO/GNS/Ag复合材料(GNS质量分数为0.5%,Ag质量分数为3%)电极表现出优异的电化学性能。在1A/g时,其初始比电容为501.66F/g,2000次循环后其比电容衰减为440.45F/g。这表明所制备的复合材料是一种有应用价值的超级电容器电极材料。     

SnO2/NiO复合半导体纳米纤维的制备及气敏性能研究

采用静电纺丝技术结合化学沉淀法和高温煅烧处理,制备了具有不同Sn含量的SnO2/NiO复合半导体纳米纤维.采用扫描电子显微镜(SEM),X射线衍射仪(XRD)和能量色散X射线光谱仪(EDS)对样品的形貌,结构以及各元素含量进行表征.以乙醇为目标气体,探究SnO2/NiO纳米纤维的气体传感性质,以及Sn含量对复合纳米纤维...     

g-C_3N_4/NiO复合材料的制备及其对AP热分解的影响EI北大核心CSCD

通过混合煅烧法制备出g-C_3N_4/NiO复合材料,采用X射线衍射(XRD)、红外光谱(FT-IR)、场发射扫描电子显微镜(FESEM)、X射线能谱(EDS)对其结构和形貌进行表征,利用差热分析(DTA)和热失重(TG)研究其对高氯酸铵(AP)热分解的影响。结果表明:纳米NiO均匀分散于g-C_3N_4的表面,g-C_3N_4/NiO使AP的高温和低温分解峰合并,高温分解温度降低62.5℃,表现出良好的催化作用。g-C_3N_4/NiO的复合催化效果优于单独使用g-C_3N_4或NiO,说明g-C_3N_4和NiO具有协同催化作用。     

碳包覆NiO纳米颗粒的制备与性能

采用直流电弧放电等离子体技术成功制备了碳包覆NiO(NiO@C)纳米颗粒,并对样品的形貌、晶体结构、粒度、比表面积和孔结构采用高分辨透射电子显微镜、X射线衍射、X射线能量色散分析谱仪、拉曼散射光谱和N_2吸-脱附等测试手段进行了分析。实验结果表明:直流电弧等离子体技术制备的NiO@C纳米颗粒具有典型的核壳结构,内核为面心立方结构的NiO纳米颗粒,外壳为碳层。颗粒形貌主要为立方体结构,粒度均匀,分散性良好,粒径分布在30~70nm范围,平均粒径为50nm,外壳碳层的厚度为5nm。NiO@C纳米颗粒BET比表面积为28m~2/g,等效直径为46nm,与TEM和XRD测得的结果基本一致。Raman光谱说明样品中碳包覆层的石墨化程度较低,发生了红移现象。     

NiO包覆Ni纳米颗粒的制备及其氧化特性研究

通过对直流电弧等离子体制备的Ni纳米颗粒钝化处理得到NiO包覆Ni纳米颗粒。并对试样的组成成分、形貌、晶体结构、粒度和氧化特性采用高分辨透射电子显微镜(HRTEM)、X射线衍射(XRD)、透射电子显微镜(TEM)和选区电子衍射(SAED)、热重和差示扫描量热分析仪(TGA/DSC)等手段进行分析。结果表明:经过表面钝化处理的NiO包覆Ni纳米颗粒具有明显的核-壳结构,内核为纳米Ni,外壳为NiO氧化物。颗粒呈球形,粒度均匀,分散性良好,粒径分布在20~70nm范围内,平均粒径为44nm,壳层氧化膜的厚度为5~8nm。壳核结构防止了纳米Ni颗粒的进一步氧化和团聚。     

ZrO2对NiO/CeO2/γ-Al2O3复合催化剂结构的影响

以Ni(NO₃)_2·6H₂O、Al(NO₃)₃·9H₂O、ZrOCl_2·8H₂O和Ce(NO₃)_3·6H₂O为原料,采用共沉淀法分别制备了NiO/CeO₂/γ-Al₂O₃和NiO/CeO₂-ZrO₂/Al₂O₃催化剂.通过X射线衍射（XRD）、透射电子显微镜（TEM）和近边X射线吸收精细结构（XANES）等方法对催化剂的组成结构进行表征.结果表明,煅烧温度高于600℃时,NiO/CeO₂/γ-Al₂O₃催化剂中的NiO与γ-Al₂O₃载体发生作用,形成NiAl₂O₄尖晶石;而NiO/CeO₂-ZrO₂/Al₂O₃催化剂中,NiO能够稳定存在,没有NiAl₂O₄尖晶石生成,且Al₂O₃与CeO₂和ZrO₂作用形成一种新的Zr_0.30Ce_0.45Al_0.25O_1.87固溶体.     

核壳结构氧化镍/碳微球的制备及葡萄糖传感性能

以碳球为模板, 六水合氯化镍和尿素为原料, 通过水热反应制备前驱体Ni(OH)₂/C, 在高纯氮气中煅烧获得核壳结构的NiO/C微球。采用扫描电镜(SEM)、X射线衍射(XRD)、X射线光谱(EDX)和热重分析(TGA)等技术手段, 分析NiO/C微球的形貌结构以及物相组成, 结果表明: NiO/C微球直径约1.4 μm, 由厚度为50 nm的纳米片包覆碳球形成花状核壳结构, NiO呈立方相。通过循环伏安法和计时电流法研究了NiO/C微球的电化学行为及葡萄糖传感能力。与单纯NiO相比, NiO/C具有优异的葡萄糖传感性能, 其灵敏度为31.37 mA/(mmol·L^-1·cm²)线性响应范围为2~1279 μmol/L, 最低检测限为2 μmol/L。该传感器具有灵敏度高、抗干扰能力强和稳定性好等特点。     

纳米NiO制备方法及其对钨系延期药性能的影响研究

为了探究纳米氧化镍(NiO)在烟火药剂中作为催化剂的应用前景,以NiSO_4·6H_2O和NaOH为原料,通过固相合成法制备出分散性良好的纳米NiO,采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对产物的粒径、形貌进行了表征,用差示扫描量热仪(DSC)研究了它的热性能。结果表明,纳米NiO与标准绿镍矿非常吻合,形状为球状颗粒,大小均一,形貌规整,平均粒径在30～40 nm。在钨系延期药中加入粒径为30～40 nm的NiO后,延期药的平均燃速提高了6. 1%,燃速标准偏差为0. 035 mm/s,DSC法对钨系延期药的分析结果表明,吸热峰和两个放热峰的起始温度分别前移了56. 2、84. 1、134. 4℃,表明纳米NiO对钨系延期药的分解具有重要的影响。     

三氧化二镍协同膨胀阻燃聚丙烯的热降解机理EI北大核心CSCD

以三氧化二镍(Ni2O3)为阻燃协效剂,采用聚磷酸铵(APP)和双季戊四醇(DPER)复配阻燃剂,制备了具有良好阻燃性能的膨胀阻燃聚丙烯。氧指数(LOI)、垂直燃烧测试(UL-94)表明,添加1%(质量分数,下同)Ni2O3,膨胀阻燃体系LOI达到28.2%,UL-94测试通过V-0级;热失重(TGA)、X射线光电子能谱(XPS)及X射线衍射分析(XRD)表明,Ni2O3使聚磷酸铵热失重速率明显降低,高温残余量显著提高;高温时,Ni2O3分解为NiO,与APP分解产生的多聚磷酸发生化学反应,形成稳定的偏磷酸镍盐,提高了多聚磷酸的热稳定性。研究表明,NiO阻止多聚磷酸分解产生P2O5的过程,使更多的多聚磷酸参与酯化反应,促进体系燃烧成炭,从而形成更加致密的膨胀炭层,提高了材料的阻燃性能。     

三氧化二镍协同膨胀阻燃聚丙烯的热降解机理

以三氧化二镍(Ni2O3)为阻燃协效剂,采用聚磷酸铵(APP)和双季戊四醇(DPER)复配阻燃剂,制备了具有良好阻燃性能的膨胀阻燃聚丙烯。氧指数(LOI)、垂直燃烧测试(UL-94)表明,添加1%(质量分数,下同)Ni2O3,膨胀阻燃体系LOI达到28.2%,UL-94测试通过V-0级;热失重(TGA)、X射线光电子能谱(XPS)及X射线衍射分析(XRD)表明,Ni2O3使聚磷酸铵热失重速率明显降低,高温残余量显著提高;高温时,Ni2O3分解为NiO,与APP分解产生的多聚磷酸发生化学反应,形成稳定的偏磷酸镍盐,提高了多聚磷酸的热稳定性。研究表明,NiO阻止多聚磷酸分解产生P2O5的过程,使更多的多聚磷酸参与酯化反应,促进体系燃烧成炭,从而形成更加致密的膨胀炭层,提高了材料的阻燃性能。     

熔融碳酸盐燃料电池LiCoO2涂覆阴极的微观结构和性能

采用溶胶-凝胶技术，制备了LiCoO2涂覆的熔融碳酸盐燃料电池NiO阴极．研究了LiC002涂覆阴极的微观组织和在Li2CO3-K2CO3熔融碳酸盐中的溶解特性，并对其电化学性能进行了测试．结果表明LiCoO2涂层有效地降低了NiO在Li2CO3-K2CO3熔盐电解质中的溶解度和溶解速率，对单电池的性能有所改善，并在一定程度上抑制了Ni在电解质基板中的沉淀．     

Stability of NiO cathode modified by ZnO additive for molten carbonate fuel cell

The preparation and subsequent oxidation of nickel cathodes modified by impregnation with zinc oxide (ZnO) were evaluated by surface and bulk analysis. The ZnO impregnated cathodes showed the similar porosity, pore size distribution and morphology as the reference nickel cathode. The stability tests of ZnO impregnated NiO cathodes in the eutectic molten Li/K carbonates showed that the ZnO additive could dramatically reduce the solubility of NiO in the melts under the standard cathode condition. The mechanism of ZnO additive on the solubility reduction of NiO cathode in the melts was also proposed in this paper. ZnO/NiO materials could be alternative cathode materials for molten carbonate fuel cells.     

Surface reaction of LiCoO2/Li system under high-voltage conditions by X-ray spectroscopy and two-dimensional correlation spectroscopy (2D-COS)

We studied the surface reactions of a LiCoO(2)/Li cell under high-voltage conditions using X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and two-dimensional correlation spectroscopy (2D-COS). 2D XPS correlation spectra show that Li(2)CO(3) is formed first by decomposition of the organic solvents, and then polycarbonate, which is formed by polymerization of the electrolytes, is produced on the cathode surface of the LiCoO(2)/Li system under high-voltage conditions. XAS measurements also confirm that the solid electrolyte interface (SEI) layer is formed on the LiCoO(2) electrode by decomposition of the organic solvents. The thickness of the SEI layer is less than 100 ?.     

The effects of substrate and annealing on structural and electrochemical properties in LiCoO2 thin films prepared by DC magnetron sputtering

LiCoO2 thin films were fabricated by direct current magnetron sputtering method on STS304 and Ti substrates. The effects of substrate and annealing on their structural and electrochemical properties of LiCoO2 thin film cathode were studied. Crystal structures and surface morphologies of the deposited films were investigated by X-ray diffraction and field emission scanning electron microscopy. The as-deposited films on both substrates have amorphous structure. The (104) oriented perfect crystallization was obtained by annealing over 600 degrees C in STS304 substrate. The LiCoO2 thin film deposited on Ti substrate shows the (003) texture after annealing at 700 degrees C. The electrochemical properties were investigated by the cyclic voltammetry and charge-discharge measurement. The 600 degrees C-annealed LiCoO2 film deposited on STS304 substrate exhibits the inithial discharge capacity of 22 uAh/cm2 and the 96% capacity retention rate at 50th cycles. The electrochemical measurement on annealed films over 600 degrees C was impossible due to the formed TiO2 insulator layer using Ti substrate. As a result, it was found that the STS304 substrate seems to be more suitable material than the Ti substrate in fabricating LiCoO2 thin film cathode.     

纳米炭复合物导电剂改进LiCoO2阴极的电化学性能

采用超声方法制备了多壁碳纳米管（MWCNTs）／乙炔黑（AB）复合物（NCCs），并用NCC作为锂离子电池LiCoO2阴极的导电剂，考察了NCC对LiCoO2阴极的电化学性能影响。结果表明：NCC作导电剂的LiCoO2阴极的电化学性能（包括首次放电比容量和容量保持率）优于MWCNTs和AB分别单独作导电剂的LiCoO2阴极的电化学性能。原因归结为两个方面：（1）NCC形成了比MWCNTs或者AB更有效的导电网络；（2）NCC和LiCoO2颗粒之间存在稳定有效的接触。     

SiO2 / Ni 核壳结构纳米粒子的制备及其磁性能

以硅酸钠为主要原料, 通过液相沉淀法在纳米镍粉表面包覆了一层SiO₂ 。应用XRD、FTIR、TEM、TGA、DSC 和VSM 对复合粉体的结构、形貌和磁性能进行了研究。结果表明, SiO₂ 以非晶态的形式包覆在纳米镍粒子表面, 形成了核壳结构, 降低了纳米粉体的团聚现象。TGA 和DSC 结果表明, SiO₂ 的包覆提高了纳米粉体的抗氧化性。磁性分析结果表明, 粉体包覆前由于表面氧化层(NiO) 的存在, 粉体的磁滞回线偏移; 包覆后的粉体由于SiO₂的存在, 饱和磁化强度降低, 矫顽力升高。      

A study of the passivating oxide layer on fine nickel particles

The surface oxide layer of fine nickel particles has been investigated by high- resolution electron microscopic observation,, electron diffraction, X-ray diffraction, X-ray photo- electron spectroscopy and temperature-programmed gas desorption experiment. The thickness of the oxide layer formed on the particles was about 2 nm. The oxide layer was composed of innermost NiO, and outermost Ni(OH)₂ and amorphous nickel carbonate-hydroxide. The oxide layer give a good thermal stability to fine nickel particles.     

The microstructure and wear resistance characteristics of electroformed nickel and partially stabilized zirconia composite coatings

Ni-PSZ composite coatings with various PSZ particle content were prepared by the electroforming technique. The microstructure and surface components of the coatings have been examined by optical microscopy, electron microscopy and X-ray photoelectron spectroscopy analysis and the wear properties of the coatings tested on a reciprocating wear test machine. The results show that the PSZ particles are uniformly dispersed in the coatings and thus increase the wear resistance of the coatings by inhibiting plastic deformation of the nickel matrix. The co-deposition of the PSZ particles in the electrolyte is mainly in the form of agglomeration and is accompanied by the incorporation of Ni(OH)₂. When the PSZ content in a coating is higher than a critical value, the wear resistance of the coating could deteriorate because of the decrease in the integrity of the nickel matrix. After heat-treatment at high temperature, Ni(OH)₂ in the coating is turned into Ni₂O₃ and NiO which can wet the PSZ particles and increase the bonding strength between the PSZ and nickel. In addition, the agglomerated PSZ particles are sintered when heat-treated. These are all beneficial to increasing the wear resistance of the coating.     

纳米氧化亚镍/玻璃微球复合粒子的制备及表征

通过均匀沉淀法,将NiO 复合于玻璃微球表面,制备了纳米NiO/玻璃微球复合粒子。X射线衍射(XRD)、扫描电镜(SEM) 结果表明,经过共沉积后,在玻璃微球表面生成一层具有面心结构的NiO 层,晶粒尺寸大约为14 nm,这些纳米NiO粒子以丝状胶连的形式附着于玻璃微球表面形成镀层。能谱分析(EDS) 结果显示,纳米NiO粒子在玻璃微球表面形成了分布均匀的镀层。傅立叶变换红外光谱仪(FTIR) 表明,所制得的纳米NiO/玻璃微球复合粒子在近红外和远红外波段都表现出良好的红外吸收特性。      

Synthesis and characterization of NiO nanoparticles and their PMMA nanocomposites obtained by in situ bulk polymerization

A nickel oxide (NiO) precursor was prepared using Pechini method. The NiO nanoparticles were prepared by calcination of NiO precursor at temperatures ranging from 300 to 700 °C. The resulting NiO nanoparticles were characterized by X-ray photoelectron spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy. To hamper NiO nanoparticles aggregation, the NiO nanoparticles surface was treated using (3-mercaptopropyl)-trimethoxysilane as a coupling agent. Next, nanocomposites of poly(methyl methacrylate) and modified NiO nanoparticles were successfully prepared by in situ bulk polymerization with 2,2′-azobis(isobutylonitrile) as initiator. The obtained nanocomposites were characterized by XRD and thermogravimetric analysis. L. A. García-Cerda is on sabbatical leave at UT-Dallas, USA.