Fabrication of n–p junction electrodes made of n-type SnO2 and p-type NiO for control of charge recombination in dye sensitized solar cells

The n–p junction electrode fabricated coating nanocrystalline SnO₂ thin film with a thin layer of p-type NiO was found to increase the sensitized photocurrent and photovoltage. In addition, increase in the fill factor was noticed due to inhibition of electron back transfer from SnO₂ to the redox electrolyte (I₃⁻) by both junction effect and presence of NiO barrier, resulting in much better energy conversion efficiencies. The highest cell efficiency was obtained for the cell fabricated by immersing SnO₂ thin films in soluble Ni salts, and converting them to NiO by firing. The optimum NiO coating thickness was found to be only a few angstroms and the energy levels of the excited dye and the conduction band position of NiO suggest that the electron transfer from the excited dye to the underlying SnO₂ layer occurs by tunneling through the p-type NiO layer.     

Preparation and characterization of nanostructured NiO thin films by reactive-pulsed laser ablation technique

Nanostructured nickel oxide (NiO) thin films were prepared using pulsed laser ablation technique on heated quartz substrates under an oxygen partial pressure of 2×10⁻³ mbar. X-ray diffraction (XRD) studies indicate enhancement in growth along (1 1 1) and (2 0 0) crystal planes with increase of substrate temperature. The atomic force microscopic (AFM) studies indicate a self-assembly of NiO nanocrystals having size 84 nm, with a uniform height profile along the assembly for films prepared at a substrate temperature of 673 K. Formation of arrays of confined two-dimensional NiO layers in the films prepared at a substrate temperature of 473 K is also reported. The optical band gap and electrical resistivity of the films synthesized under different deposition conditions are also discussed.     

Facile synthesis of hierarchically structured NiO flower-like hollow spheres

The hierarchical flower-like NiO hollow spheres were synthesised by a facile method without using any templates or surfactants. The as-prepared sample and precursor were characterised by X-ray diffraction and field emission scanning electron microscopy. The results indicated that the as-prepared NiO is self-assembled hierarchically. During the assembly of NiO, the reaction time plays an important role. The flower-like NiO hollow sphere showed much higher catalytic activity than large-size NiO or hollow NiO for the oxidative dehydrogenation of ethane to ethylene due to its special structure.     

Environmental remediation of thiophene solution by photocatalytic oxidation using NiO/AgInS2 nanoparticles

AgInS₂ nanoparticles were prepared via a microwave method, while NiO was immobilized on the surface of AgInS₂ via an impregnation method. The samples produced were characterized using different techniques. The catalytic performances of the AgInS₂ and NiO/AgInS₂ samples were carried out for photocatalytic oxidation of thiophene under visible light. The maximum oxidation efficiency achieved was 100% at 0.3 NiO/AgInS₂ photocatalyst. The doping of NiO into the AgInS₂ was useful in improving the photocatalytic activity. The catalyst could be reused without any loss in activity during the first five cycles.     

LaxSr1-xNiO3复合氧化物化学电极动力学研究

甘氨酸燃烧法合成了LaxSr1-xNiO3复合氧化物,此陶瓷粉末具有高的比表面积,用来制备氧电极具有双功能氧电极特性。讨论了氧还原和氧析出时的电化学反应机理。在1mol·L-1KOH溶液里减少铂电极的面积,加入碘化钾催化剂可以成为4电子反应。通过不同温度下LaxSr1-xNiO3(x=0.15,0.70,0.75,1.00)的功能氧电极循环伏安曲线,得出化学动力学参数lnIc与1/T,-lnVa与1/T成直线关系,得到氧还原和氧析出的活化能;通过改变扫描速度,分析循环伏安曲线,可知氧气吸附在功能氧电极表面,同时可以看到,当加入8.6×10-3g/mL碘化钾(KI)时,两个氧化峰变成一个峰,氧析出电势从0.94V减少到0.62V(相对于饱和甘汞电极),同时氧还原峰突然下降,可以预测,通过减少铂电极面积,加热溶液,加入碘化钾催化剂,使氧电极更有效。     

沉淀法合成NiO及NiO-YSZ阳极性能

用硝酸盐-氨水沉淀法合成了NiO纳米粉体,X-射线粉末衍射结果表明样品为面心立方结构,颗粒的平均粒径为23nm。以此纳米NiO为原料,制备NiO-YSZ阳极,阳极的高温烧结收缩比YSZ电解质小6%。高温H2还原电阻测量表明该阳极在700℃时10min完成还原,电导率为570S/cm。在NiO-YSZ阳极上用离心沉积方法制备了一层厚12μmYSZ薄膜,扫描电子显微镜测试结果表明阳极和电解质薄膜之间的接触良好。采用Sm0.2Ce0.8O1.9浸渍的La0.7Sr0.3MnO3阴极,单电池在750℃时的最大比功率为0.52W/cm2,测试结果还表明该阳极具有合理的孔隙率:说明采用硝酸盐-氨水沉淀法合成的NiO可以应用于制备固体氧化物燃料电池的阳极。     

乙醇水蒸汽重整制氢催化剂NiO-CeO2/ZnO研究

通过共沉淀法制备了一系列添加CeO2改性的NiO/ZnO催化剂,并采用X射线衍射光谱法(XRD)、扫描电子显微镜(SEM)等手段进行了表征,发现:适量CeO2的加入可以有效地促进NiO的分散,减小NiO颗粒的大小。同时对CeO2改性的NiO/ZnO催化剂进行了测试发现:CeO2含量为5%(质量分数)的NiO/ZnO催化剂氢气选择性最好。350℃时,氢气的选择性就可达61.66%,并随温度的升高而升高,在650℃时,氢气的选择性达到68.37%。5Ce催化剂650℃30h稳定性测试发现,氢气的选择性一直保持在68%以上,没有明显的下降。     

NiO活性对高频低磁导率NiCuZn铁氧体Q值的影响

以不同工艺生产的NiO为原材料,制备了高频低磁导率NiCuZn铁氧体.用扫描电镜(SEM)分析原材料NiO的微观形态的差异,用X射线衍射(XRD)研究预烧后固相反应的进行状况,考察了不同NiO材料对低温烧结材料高频Q值的影响.研究发现,低温烧结条件下,高活性的NiO原材料能有效提高低磁导率NiCuZn铁氧体的高频Q值.     

高Bs的NiZn铁氧体材料的研制

以高纯度的NiO、ZnO、Fe2O3为原料,采用氧化物陶瓷工艺制备了高Bs NiZn铁氧体材料.通过岩崎B-H Analyzer SY-8232、Agilent 4285A和4284A多频LCR测试仪分析了NiO含量对材料的饱和磁感应强度、起始磁导率、Q值的影响;通过扫描电镜(SEM)观测样品的晶粒.结果表明,当NiO、ZnO、Fe2O3含量比为0.6:0.4:1、烧结温度为1140℃时,材料饱和磁感应强度大于480mT.     

Mo在NiO/Al_2O_3-TiO_2催化剂中助催化作用的研究

采用引入钼组分的办法,调变NiO-TiO2-Al2O3体系的性能。TPR结果发现,含Mo催化剂产生了还原性能不同的多 种镍原子位。当n(Ni):n(Mo)=3．04时,形成了3个还原峰:峰Ⅰ为362．5℃,与纯NiO的最高还原峰接近;峰Ⅱ位于 482．1-491．6℃之间,与NiO-TiO2-Al2O3催化剂tm为483．4℃接近,峰形都比较宽;在430．2℃还存在1个还原态(峰 Ⅲ),说明骨架内作用的复杂性。可以推测,催化剂中加入Mo后,减弱了Ni与载体之间的相互作用力,生成了容易被还原的, 类似于纯NiO样品的Ni原子位。同时,Mo的引入增加了NiO-TiO2-Al2O3催化剂的氢化学吸附量。在Mo含量较低时,即 当n(Ni):n(Mo)=5．22和9．47时,表面镍原子浓度不高,耗氢量也低于粉状纯NiO催化剂的。随着Mo含量的增加,当 n(Ni):n(Mo)=3．69和3．04时,表面镍原子浓度高,单位质量金属镍的耗氢量远高于其它样品。证明Mo的突出作用是 提高了催化剂中活性组分镍的分散度。高钼的NiO-MoO3-TiO2-Al2O3型催化剂的选择性加氢脱芳烃精制煤油的芳烃含量 平均低于200 μg/g,所用的反应条件是,反应温度180℃,压力1．2 MPa,LHSV2．0 h-1,氢油体积比500: 1。表明n(Ni) :n(Mo)=3．04-5．22的NiO-MoO3-TiO3-Al2O3型催化剂的加氢脱芳烃性能满足煤油脱芳烃和除味的要求。