微波反应时间对纳米片状氧化镍微球的形貌及电性能影响

以硝酸镍为镍源,采用微波辅助法导电基底Ni网上原位生长氧化镍微球,讨论了微波反应时间对纳米片状氧化镍微球结构和形貌的影响。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电子显微镜(TEM)对其结构和形貌做了表征。结果表明,反应时间对产物结构和形貌具有较大的影响,当微波功率为100 W、反应时间为1.5 h时,电极的电流密度为1 A/g,电极的比容量达到350 F/g,并呈现出较好的倍率特性。

基于中空氧化镍纳米微球和离子液体复合膜固定血红蛋白的NaNO_2生物传感器

采用微波水热法合成了一种中空氧化镍纳米微球(NiO),然后将其与1-丁基-3-甲基-咪唑四氟硼酸盐(BMIMBF4)的复合膜用于血红蛋白(Hb)在碳糊电极上的固定,制备了NaNO2生物传感器.通过扫描电子显微镜、傅里叶变换红外光谱及紫外-可见光谱等分析表明,Hb已固定于NiO和BMIMBF4的复合膜中并能保持其生物活性;进一步通过电化学阻抗法研究了修饰电极中混合物各组分的作用.结果表明,在NiO和BMIMBF4的复合膜中,Hb能实现有效的直接电子转移,且修饰后的电极对NaNO2有良好响应,响应时间小于5 s,检出限为4.57μmol/L(S/N=3),灵敏度为46.2μA.L.mmol-1,线性范围为10～170μmol/L,表观米氏常数KM为2.4 mmol/L,该方法的重现性和电极的稳定性良好.

氧化镍/碳@碳纳米管负极材料的制备及储锂性能(英文)

将核壳的聚吡咯基的碳@碳纳米管(C@CNT)与纳米片组装的氧化镍(Ni O)微球结合,制备了一种多孔的锂离子电池负极材料(Ni O/C@CNT),该材料(Ni O/C@CNT)与纯的Ni O和Ni O/CNT相比,其容量值和循环稳定性能明显提高。在50 m A·g-1的电流密度下,经过20次循环后,其可逆容量达到573 m A·g-1,容量保持率为68.6%。这些性能的提高是由于核壳结构的C@CNT的导电缓冲性引起的。C@CNT具有诸如多孔结构、大比表面积、高电化学活性、高电子导电性和良好的浸润性等许多优点,这些优点有利于避免电极材料显著的体积变化,因此在锂嵌入和脱出过程中可减少电极容量衰减并提高传质速率。

Controllable preparation of hierarchical NiO hollow microspheres with high pseudo-capacitance

Nickel oxide(NiO)hollow microspheres with hierarchical structure were fabricated through a process consisting of a self-assembling,hydrothermal reaction and calcination.The prepared NiO hollow microspheres composed of many nanoflakes,are about 2-3μm in diameter.The length of the NiO flakes,having clear edges,is about 500-700 nm,while the thickness is only about 40-50 nm.This indicates that the NiO microspheres possess a hierarchical structure that can provide porous channels to facilitate the transmission of both electrons and electrolyte ions.NiO microspheres exhibit a high specific capacitance of about 1340 F/g at a current density of 1 A/g and high capacitance retention about 96.5%after 1000 cycles.What’s more,the conductive mechanism of nickel oxide for electrochemical capacitor electrodes was also studied.

Coating of Fe, Ni on α-alumina microspheres by heterogeneous precipitation

The precursors with NiCO3·2Ni（OH）2·2H2O, Fe2O3·nH2O coated alumina microspheres were prepared by the aqueous heterogeneous precipitation using metal salts, ammonium bicarbonate and α-Al2O3 micropowders as the starting materials. Magnetic metal Ni, α-Fe coated alumina, core-shell structural microspheres were successfully obtained by thermal reduction of the precursors at 700℃ for 2h, respectively. Powders of the precursors and the resultant metal （Ni, α-Fe） coated alumina micropowders were characterized by scanning electron microscopy, energy dispersive spectroscopy and X-ray diffraction. The results show that optimized precipitation parameters are concentration of alumina micropowders of 15g/L, rate of adding reactants of 5mL/min and pH value of 7.5. And under the optimized conditions, the spherical precursors without aggregations or agglomerations are obtained, then transferred into Ni, α-Fe coated alumina microspheres by thermal reduction. It is possible to adjust metal coating thicknesses and fabricate a multilayer structured metal/ceramics, core-shell microspherical powder materials.

3D flower-like heterostructured TiO_2@Ni(OH)_2 microspheres for solar photocatalytic hydrogen production

TiO2@Ni(OH)2 core-shell microspheres were synthesized by a facile strategy to obtain a perfect 3D flower-like nanostructure with well-arranged Ni(OH)2 nanoflakes on the surfaces of TiO2 microspheres;this arrangement led to a six-fold enhancement in photocatalytic hydrogen evolution. The unique p-n type heterostructure not only promotes the separation and transfer of photogenerated charge carriers significantly, but also offers more active sites for photocatalytic hydrogen production. A photocatalytic mechanism is proposed based on the results of electrochemical measurements and X-ray photoelectron spectroscopy.

Novel synthesis of nickel oxide microsphere with high surface area and its catalytic application for carbon dioxide reforming of methane

Nickel oxide(NiO)microsphere with a large surface area was novelly synthesized through nickel bicarbonate(Ni(HCO3)2)precursor.The obtained nickel oxide(NiO)microsphere was characterized by X-ray pattern diffraction,scanning electron microscopy,CO2 temperature-programmed desorption,H2 temperature-programmed reduction,N2 adsorption/desorption and laser scattering particle size distribution analyzer.It was found that nickel oxide(NiO)synthesized by the thermal decomposition of Ni(HCO3)2through area hydrolysis,presented very nice microsphere with high surface area.The catalytic properties of obtained nickel oxide(NiO)microsphere were studied in the reaction of carbon dioxide reforming of methane where 91.3% conversion of CH4 with 93% conversion of CO2 was observed.Besides,the catalyst maintained high stability over 200 h on the stream.