Sol-gel based alumina powders with catalytic applications

The sol-gel process provides a new approach to the preparation of oxide materials and offers many advantages for making catalysts. Since homogeneous mixing can be achieved at the molecular scale, the chemical reactivity of the oxide surface can be greatly enhanced; thus powders with high surface area and optimized pore size distribution can be obtained at low temperatures. In the present work NiO/Al₂O₃ sol-gel catalysts were obtained by simultaneous gelation of aluminium isopropoxide and nickel nitrate. A comparative study with pure sol-gel alumina was also realized. By physical-structural studies the changes induced by the introduction of the Ni precursor, before and after aluminium alkoxide hydrolysis were highlighted. The introduction of Ni at the beginning of the reaction favors γ-Al₂O₃ crystallization. When Ni is added at the end of reaction, it delays the alumina crystallization and induces the disorder of the lattice. The obtained Ni doped sol-gel derived alumina has been used as catalyst in the finished form for glycerol reforming to generate H₂ for fuel cell applications. Some evaluation results of Ni-doped alumina combined with TiO₂ in photocatalytic glycerol reforming reaction have been included.     

Graphene oxide decorated bimetal (MnNi) oxide nanoflakes used as an electrocatalyst for enhanced oxygen evolution reaction in alkaline media

Precious non-noble metals have been constantly attracting research attention in order to realize an inexpensive, extra active and more stable electrocatalysts in terms of various oxidation states and structures for their applications in oxidation (splitting) of water. In the present work graphene oxide incorporated, MnO₂-NiO composite metal oxide nanoflakes were synthesized on the stainless steel substrate using efficient electrodeposition route in alkaline media and drop casting method with further annealing treatment at 400 °C for 4 h. Initially MnO₂-NiO nanoflakes were deposited using different cyclic sweep rates, later graphene oxide suspension was drop casted on the MnO₂-NiO nanoflakes and subsequently subjected to annealing at 200 °C for 2 h. The prepared electrode material is denoted as GO/MnO₂-NiO/SS and used as an electrocatalyst for oxygen evolution. Field emission scanning electron microscopy, transmission electron microscopy, Energy dispersive electron spectroscopy and X-ray diffraction spectroscopy were used to study the crystalline nature and morphologies of the deposited films. The electrochemical properties of the electrode material were investigated using cyclic voltammetry and linear sweep voltammetry. The electrode exhibits low overpotential and small Tafel slope of 379 mV and 47.84 mVdec⁻¹ at the current density of 10 mA cm⁻² in alkaline (KOH) medium. In addition, the electrode shows a long time stability of 28800 s. Hence, the present study suggests that the GO incorporated Mn-Ni bimetal oxide modified electrode is suitable electrode material for oxygen evolution reaction (OER), owing to its facile preparation, inexpensive, easy handling and high active nature.     

Nickel oxide nanoparticles catalyzed synthesis of poly-substituted quinolines via Friedlander hetero-annulation reaction

Reusable acidic nickel oxide nanoparticles have been synthesized,characterized and applied as a catalyst to convert 2-aminoaryl ketones and β-ketoesters/ketones into the corresponding quinolines in good yields with high selectivity.This could serve as a simple and convenient procedure for the Friedlander annulations.     

锂离子电池纳米NiO负极材料的制备

采用乳液法制备了Ni(OH)2前驱体,在空气氛中、500℃下煅烧2h得到NiO材料,采用XRD、SEM、充放电测试和循环伏安实验对其结构、形貌和性能进行表征.结果表明,粒状结构的纳米NiO材料具有良好的循环性能,40次循环内可逆比容量无明显衰减.第40次循环的可逆比容量为400mA.h/g,库仑效率为95%.     

阴离子对鼠尾草提取物中Ni盐前体绿色合成的NiO纳米粒子磁性和结构性能的影响

采用绿色合成方法,将鼠尾草提取物用作还原和封端剂合成氧化镍纳米颗粒(NiO NPs)。此外,使用各种前驱体合成了NiO NPs,并使用扫描电子显微镜对其形貌进行了分析。利用傅里叶变换红外光谱和粉末X射线衍射(PXRD)对NiO NPs的结构进行了表征,使用振动样品磁强计测量了它们的磁性。PXRD研究表明,所有合成的NiO NPs都表现出具有高结晶度的面心立方相,并且形成了具有高纯度相的NiO。磁化研究结果表明,3种镍盐(乙酸盐、氯化物和硫酸盐)前驱体合成的NiO NPs分别表现出超顺磁、软铁磁和顺磁行为。     

50 GPa下NiO等温状态方程的高压X光研究

 本文采用在位的（in situ）高压X光衍射方法研究了近50 GPa和室温下三方结构NiO的等温压缩行为，并用Murnaghan状态方程对实验值进行了最小二乘法拟合，得到的NiO室温状态方程的相应参量分别为：B₀=223 GPa，B₀'=4.21。在室温压力范围内没有观察到第一类结构相变。NiO在六方指标下的轴比c/a随压力的变化在实验压力范围内可用c/a=2.450~1.569×10^-3（GPa）近似描述。     

A novel amperometric biosensor based on NiO hollow nanospheres for biosensing glucose

NiO hollow nanospheres were synthesized by controlled precipitation of metal ions with urea using carbon microspheres as templates, which were for the first time adopted to construct a novel amperometric glucose biosensor. Glucose oxidase was immobilized on the surface of hollow nanospheres through chitosan-assisted cross-linking technique. Due to the high specific active sites and high electrocatalytic activity of NiO hollow nanospheres, the constructed glucose biosensors exhibited a high sensitivity of 3.43 μA/mM. The low detection limit was estimated to be 47 μM (S/N = 3), and the Michaelis-Menten constant was found to be 7.76 mM, indicating the high affinity of enzyme on NiO hollow nanospheres to glucose. These results show that the NiO hollow nanospheres are a promising material to construct enzyme biosensors.     

Preparation and characteristics of NiO-coated nano-fibriform silica

NiO-coated nano-fibriform silica (NFS) was prepared by an excessive soakage method and was characterized using transmission electron microscopy, X-ray diffraction, and physical N₂ adsorption techniques under different conditions. The results demonstrate that the coated NiO is of a cubic crystal form. The best preparation conditions are incubation in a water bath at 95 °C for 2 h and drying at 45 °C for 17 h, which lead to a higher NFS utilization ratio and thus lower cost, and a well-distributed NiO coating on the carrier NFS. Nitrogen adsorption isotherms for NiO-coated NFS are similar to a type IV curve, with a specific surface area of 292.7 m²/g, adsorptive capacity of 379.2 cm³/g, and pore volume of 0.59 cm³/g. The average pore diameter of NiO-coated NFS is 8.01 nm, but most pore diameters are in the range 2.1–3.9 nm. Comparison of NiO-coated NFS and NiO(Ni)-coated sol–gel silica as catalysts reveals that NiO-coated NFS may be an effective catalyst and that NFS may be a good catalyst carrier.     

NiO/ZnO Composite Derived Metal-Organic Framework as Advanced Electrode Materials for Zinc Hybrid Redox Flow Battery

NiO/ZnO composite derived metal-organic framework (MOF) is used as to modify carbon felt (CF) via a conventional solid-state reaction followed by ultrasonication. The prepared electrode material is used in zinc-hybrid redox flow batteries (RFBs) due to their high redox activity of Zn²⁺/Zn. The electrochemical performance of composite modified CF and pre-treated CF was studied by cyclic voltammetry (CV) in 0.5 M aqueous zinc chloride with 5 M potassium hydroxide solutions showed clear confirmation for enhanced electrocatalytic activity. The unique porous structure of NiO/ZnO-derived MOF with increased surface area improves the battery behavior significantlyThe peak current ratio for the as-prepared material is about 3 times higher than that of the pre-treated CF due to more active sites. Zinc-based RFB with modified CF electrode exhibited better electrochemical performance with voltage efficiency (VE, 88 %), which is higher than true redox flow batteries.     

氧气含量对射频磁控溅射方法制备的NiO∶Cu/ZnO异质pn结的光电性能的影响

利用磁控溅射方法改变氧气含量制备了一系列NiO∶Cu/ZnO异质pn结。实验结果表明,氧含量对NiO∶Cu/ZnO异质pn结电学影响很大。相对于纯氩溅射,引入一定氧气(O2/(Ar+O2)比例为30%)后,NiO∶Cu/ZnO异质pn结的整流特性明显得到改善。与此同时,NiO∶Cu/ZnO异质pn结的光透过率也从40%增大到80%。这可能是由于氧气的轻量引入致使NiO∶Cu/ZnO异质pn结的结晶得到改善,薄膜内缺陷减少所致。进一步提高氧气含量,直到O2/(Ar+O2)比例至80%后,异质结的整流特性有所削弱,这可能是由于过多氧气的引入造成薄膜缺陷再次增多,进而影响到异质结的整流特性。这一结论得到了EDS、XRD、AFM和UV结果的支持。