废镍触媒氨浸法制取一氧化镍

介绍了利用废镍催化剂制取一氧化镍的新工艺。进一步提高了镍的回收率,使镍的回收率达95%以上。产品质量达国家工业品标准。

熔盐电解氧化亚镍制备镍粉新工艺研究

提出了以NiO为原料经一步熔盐电解得到高纯镍粉新工艺,具有工艺流程短、低能耗、无环境污染等特点。在850℃的CaCl2熔盐中,以烧结后的NiO片作为阴极,高密度石墨棒作阳极,进行电解。记录电解过程中电流变化,利用X射线衍射仪分析电解产物的成分,并用扫描电子显微镜分析不同工艺条件下压片在烧结前、后和电解后的表面及断面形貌。研究了不同的压片压力、烧结温度、烧结时间等因素对阴极形貌及其对电脱氧反应的影响。结果表明采用熔盐电解NiO粉末直接制备金属Ni的最佳的工艺条件为:NiO粉末在10 MPa下压片,900℃烧结10 h后,在850℃的CaCl2熔盐中加3.2 V槽电压下电解约9 h。

NiO催化甲酸分解机理的密度泛函研究

在B3LYP/ 6 311G(d)水平上研究了NiO催化的HCOOH→CO +H2 O和HCOOH→CO2 +H2 两个反应的单态势能曲线 .结果表明 ,在NiO上甲酸容易解离吸附形成甲酸盐HONiOCOH ,甲酸盐的分解是上述两个反应的速率决定步骤 ,这两个反应的活化能大致相当 .在脱水反应中 ,HCOOH和NiO之间存在着氧交换 ,但脱氢反应中不存在氧交换 .甲酸盐发生脱氢反应还是脱水反应取决于甲酸盐是用其羟基中的H还是用O去进攻甲酸根中的H原子 .

NiO制备工艺对超电容器比电容的影响

以硝酸镍为原料,采用sol-gel法制备Ni(OH)2,在不同温度下,用真空烧结炉和管式电阻炉对其热处理后得到NiO,与活性炭电极组成非对称超级电容器研究了NiO制备工艺对超电容器比电容影响。结果表明:Ni(OH)2经真空烧结炉处理所得NiO的比电容均高于管式电阻炉处理,在260℃保温时间为1 h真空度为0.5 Pa时比电容达最大481.15 F/g。

氨水沉淀法制备纳米NiO中溶液的反应与竞争平衡

以NiCl2 ·6H2 O为原料 ,水为沉淀剂 ,在常温下 ,用水作溶剂 ,通过单相沉淀法制备出纳米NiO。该法简化了操作程序、降低了加工成本 ,且原料易得价廉 ,便于实现工业化生产。该法的关键是如何控制好溶液中的化学反应及其竞争平衡 ,本文从原理到应用作了详细的阐述。

TiC@NiO核壳纳米结构的制备及电化学储能性能

以棉纤维为碳源和模板,采用生物模板法成功合成出直径50～200nm、长度几至十几微米的碳化钛纳米线,并通过化学浴沉积法在其表面均匀沉积氧化镍纳米片,所构建的TiC@NiO核壳纳米结构具有良好的超电容性能,制备成超级电容器后在1A/g电流密度下比电容量为560F/g,而类似条件下制备的NiO材料的比电容量仅为193.5F/g,并且TiC@NiO在20A/g电流密度下循环5000次后容量保持率达到83.6%,表现出了良好的循环稳定性。

模板法合成NiO@Co_3O_4空心多孔小球及其储电性能的研究（英文）

空心结构在能量转化和储存等重要应用方面,展现出了巨大的潜力.为了进一步提高性能,根据物质的组成和结构,合理设计出更复杂的空心结构材料是非常必要的,但目前仍然存在相当大的挑战.本文报导了一种以硅小球作为模板的高效方法,合成了新型的NiO@Co_3O_4空心多孔小球,其比表面积可达219.68 m2·g-1.NiO@Co_3O_4空心多孔小球的高比表面积有利于增强离子的扩散和提高活性物质的利用效率,并可防止纳米颗粒团聚.测试结果表明,在5 m V·s-1的扫描速度下,所制备的NiO@Co_3O_4空心多孔小球的比电容值达1140.9 F·g-1,同时具有良好的循环稳定性,显示出该材料在超级电容器领域有较好的应用前景.

Promotion effects of nickel-doped Al2O3-nanosheet-supported Au catalysts for CO oxidation

Supported gold catalysts show high activity toward CO oxidation, and the nature of the support significantly affects the catalytic activity. Herein, serial Ni doping of thin porous Al2 O3 nanosheets was performed via a precipitation-hydrothermal method by varying the amount of Ni during the precipitation step. The prepared nanosheets were subsequently used as supports for the deposition of Au nanoparticles(NPs). The obtained Au/Nix Al catalysts were studied in the context of CO oxidation to determine the effect of Ni doping on the supports. Enhanced catalytic performances were obtained for the Au/Nix Al catalysts compared with those of the Au supported on bare Al2 O3. The Ni content and pretreatment atmosphere were both shown to influence the catalytic activity. Pretreatment under a reducing atmosphere was beneficial for improving catalytic activity. The highest activity was observed for the catalysts with a Ni/Al molar ratio of 0.05, achieving complete CO conversion at 20 °C with a gold loading of 1 wt%. The in-situ FTIR results showed that the introduction of Ni strengthened CO adsorption on the Au NPs. The H2-TPR and O2-TPD results indicated that the introduction of Ni produced new oxygen vacancies and allowed the oxygen molecules to be adsorbed and activated more easily. The improved catalytic performance after doping Ni was attributed to the smaller size of the Au NPs and more active oxygen species.

Effect of decomposition of catalyst precursor on Ni/CeO_2 activity for CO methanation

CO methanation on Ni/CeO2 has recently received increasing attention.However,the low-temperature activity and carbon resistance of Ni/CeO2 still need to be improved.In this study,plasma decomposition of nickel nitrate was performed at ca.150℃ and atmospheric pressure.This was followed by hydrogen reduction at 500 ℃ in the absence of plasma,and a highly dispersed Ni/CeO2 catalyst was obtained with improved CO adsorption and enhanced metal-support interaction.The plasma-decomposed catalyst showed significantly improved low-temperature activity with high methane selectivity(up to 100%)and enhanced carbon resistance for CO methanation.For example,at 250 ℃,the plasma-decomposed catalyst showed a CO conversion of 96.8% with high methane selectivity(almost 100%),whereas the CO conversion was only 14.7% for a thermally decomposed catalyst.

Boosting ethanol oxidation over nickel oxide through construction of quasi-one-dimensional morphology and hierarchically porous structure

Quasi-one-dimensional NiO with a hierarchically porous structure was synthesized through a facile coordination−precipitation method with the coupling effect of ammonia and a post-calcination treatment.The electrocatalytic properties of NiO fibers for the oxidation of ethanol were compared with those of NiO spheres.The results show that the fibrous NiO possesses a larger specific surface area of 140.153 m2/g and a lower electrical resistivity of 4.5×105Ω·m,leading to an impressively superior electrocatalytic activity to spherical NiO for ethanol oxidation in alkaline media.The current decay on fibrous NiO at 0.6 V in 100−900 s was 0.00003%,which is much lower than that of spherical NiO,indicating its better stability.The unique morphology and hierarchically porous structure give the fibrous NiO great potential to be used as an anodic electrocatalyst for direct ethanol fuel cells.

Near Ambient Pressure Adsorption of Nickel Carbonyl Contaminated CO on Cu(111) Surface

Formation of volatile nickel carbonyls with CO in catalytic reaction is one of the mechanisms of catalyst deactivation. CO is one of the most popular probe molecules to study the surface properties in model catalysis. Under ultra-high vacuum (UHV) conditions, the problem of nickel carbonyl impurity almost does not exist in the case that a high purity of CO is used directly. While in the near ambient pressure (NAP) range, nickel carbonyl is easily found on the surface by passing through the Ni containing tubes. Here, the NAP techniques such as NAP-X-ray photoelectron spectroscopy and NAP-scanning tunneling microscopy are used to study the adsorption of nickel carbonyl contaminated CO gas on Cu(111) surface in UHV and NAP conditions. By controlling the pressure of contaminated CO, the Ni-Cu bimetallic catalyst can form on Cu(111) surface. Furthermore, we investigate the process of CO adsorption and dissociation on the formed Ni-Cu bi-metal surface, and several high-pressure phases of CO structures are reported. This work contributes to understanding the interaction of nickel carbonyl with Cu(111) at room temperature, and reminds the consideration of CO molecules contaminated by nickel carbonyl especially in the NAP range study.

The role of alkali promoters in enhancing the direct N_2O decomposition reactivity over NiO catalysts

Direct N2O decomposition has been investigated over bare NiO and a series of its alkali-promoted catalysts. These catalysts were characterized by X-ray diffractometry, X-ray photoelectron spectroscopy （XPS） and field emission scanning electron microscopy. XPS analysis revealed that surface nickel is present in three forms： metal particles, NiO and Ni（OH）2. It is suggested that nickel（0） valent atoms are essential for the interaction with N2O molecules at the catalyst surfaces. Bare NiO exhibited a very low N2O decomposition reactivity. However, the alkali-containing catalysts exhibited a marked activity enhancement.

镍化合物致氧化应激损伤机制的研究进展

镍化合物（nickel compounds）是广泛使用的工业原料或产品,工业生产中常见的镍化合物主要有氧化镍（Ni2O3）、一氧化镍（NiO）、硫酸镍（NiSO4·7 H2O）、氢氧化镍[Ni（OH）2]、氯化镍（NiCl2）、硝酸镍[Ni（NO3）2·6H2O]和羰基镍[Ni（CO）4]等,其中,氧化镍、羰基镍和硫酸镍等是一类多器官毒物。

Acid promoted Ni/NiO monolithic electrode for overall water splitting in alkaline medium

Exploring and designing bi-functional catalysts with earth-abundant elements that can work well for both hydrogen evolution reaction（HER） and oxygen evolution reaction（OER） in alkaline medium are of significance for producing clean fuel to relieve energy and environment crisis.Here,a novel Ni/NiO monolithic electrode was developed by a facile and cost-effective acid promoted activation of Ni foam.After the treatment,this obtained monolithic electrode with a layer of NiO on its surface demonstrates rough and sheet-like morphology,which not only possesses larger accessible surface area but also provides more reactive active sites. Compared with powder catalysts,this monolithic electrode can achieve intimate contact between the electrocatalyst and the current collector,which will alleviate the problem of pulverization and enable the stable function of the electrode. It can be served as an efficient bi-functional electrocatalyst with an overpotential of 160 mV for HER and 290 mV for OER to produce current densities of 10 mA cm^（-2） in the alkaline medium. And it maintains benign stability after 5,000 cycles,which rivals many recent reported noble-metal free catalysts in 1.0mol L^（-1） KOH solution. Attributed to the easy,scalable methodology and high catalytic efficiency,this work not only offers a promising monolithic catalyst but also inspires us to exploit other inexpensive,highly efficient and self-standing noble metalfree electrocatalysts for scale-up electrochemical water-splitting technology.