共查询到19条相似文献,搜索用时 62 毫秒
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为了改善Ni(OH)2的电化学性质,提高锌镍电池的充放电性能,用化学共沉淀法合成了混合铝镍氢氧化物Ni/Al(OH)x.用XRD和FTIR表征了Ni/Al(OH)x样品的晶体结构及IR光谱特征;测试了用Ni/Al(OH)x为正极活性物质的Zn/Ni实验电池的充放电性能.研究结果表明:所合成的Ni/Al(OH)x具有α-Ni(OH)2的晶体结构;Ni/Al(OH)x活性物质在充放电过程中主要为γ/α循环,以Ni/Al(OH)x作为正极活性物质的Zn/Ni试验电池具有优良的循环性能,其最高放电比容量为379mA·h/g. 相似文献
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采用水热合成法制备出一种新型β-Ni(OH)2/碳纳米管(CNTs)纳米复合物,Ni(OH)2微晶粒径控制在50~80 nm之间,与CNTs直径相当,CNTs与Ni(OH)2质量比为1:15.将纳米复合物应用于活性炭(AC)/NiOOH电化学混合电容器,电化学测试表明:在0.4 A/g电流条件下,其放电比容量达279 mAh/g,是β-Ni(OH)2理论容量的96.5%;当电流密度从0.4 A/g增加至8 A/g时,电容器的容量保持率在76.5%以上,高倍率充放电特性优异.此外,纳米复合物良好的电化学可逆性使AC/NiOOH电化学混合电容器更易活化,并具有较高的充放电效率和良好的循环稳定性能. 相似文献
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采用溶剂热法制备了氢氧化镍/多壁碳纳米管[Ni(OH)2/MWCNTs]复合纳米材料;借助X射线衍射仪和透射电镜分析了产物的结构和形貌,利用循环伏安测试测定了复合材料的电容特性.结果表明:片状β-Ni(OH)2较好地附着在MWCNTs上;复合样品的循环伏安行为明显有别于空白样品Ni(OH)2,峰电流较高.这表明引入MWCNTs可改善Ni(OH)2的电化学性能.与此同时,当MWCNTs的质量分数为10%时,相应的Ni(OH)2/MWCNTs复合物的氧化还原峰电位差最小,循环可逆性最佳. 相似文献
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目前镍基碱性二次电池正极活性物质广泛采用的β-Ni(OH)2存在比容量偏低、不能或不适合与单质锌直11接搭配制作一次或二次锌镍电池等缺点[1],因此,合成充电态高比容量的NiOOH具有重要意义.Al、Zn等掺杂改性的α-Ni(OH)2在强碱性电解质中稳定,充放电可逆性好,质量比容量可达400mAh/g以上[2~4],如果直接合成其氧化态物质γ-NiOOH,有望获得较好的电性能,从而为镍基碱性电池提供一种新型的正极活性材料. 相似文献
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采用水热合成法制备出一种新型β-Ni(OH)2/碳纳米管(CNTs)纳米复合物, Ni(OH)2微晶粒径控制在50~80 nm之间, 与CNTs直径相当, CNTs与Ni(OH)2质量比为1∶15. 将纳米复合物应用于活性炭(AC)/NiOOH电化学混合电容器, 电化学测试表明: 在0.4 A/g电流条件下, 其放电比容量达279 mAh/g, 是β-Ni(OH)2理论容量的96.5%; 当电流密度从0.4 A/g增加至8 A/g时, 电容器的容量保持率在76.5%以上, 高倍率充放电特性优异. 此外, 纳米复合物良好的电化学可逆性使AC/NiOOH电化学混合电容器更易活化, 并具有较高的充放电效率和良好的循环稳定性能. 相似文献
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Nail Altunay Adil Elik Cüneyt Bulutlu Ramazan Gürkan 《International journal of environmental analytical chemistry》2018,98(7):655-675
In this study, a simple, fast and eco-friendly ultrasound-assisted-cloud point extraction method for extraction and pre-concentration of zinc, nickel and cobalt from vegetables and foods prior to their determination by flame atomic absorption spectrometry (FAAS) was proposed. Ultrasound energy was used to shorten extraction time and reduce steps needed or to improve selectivity. The method is based on complex formation of metal ions with carmine in presence of cationic surfactant at pH 5.0, and then extraction of their hydrophobic complexes into the micellar phase of Igepal CO-630 as extractant. After optimisation, calibration curves for Zn, Co and Ni were linear in the range of 2–120, 2–220 and 2–180 μg kg?1, respectively. Limits of detection, which is described as ratio of 3×standard deviation of 12 replicate measurements of blank analysis to slope of calibration curves, were 0.5, 0.6 and 0.6 μg kg?1 for Zn, Ni and Co, respectively. Relative standard deviations (RSDs%, n: 5) for 25 μg kg?1 of each analyte were less than 3.1%. The recovery rate was higher than 94% with a lower RSD than 3.1% for five replicate measurements of 25 μg kg?1 of each analyte. The accuracy was verified using two different standard reference materials (SRM 1570a-Trace elements in spinach leaves and SRM 1548a-Typical diet), and the results were in good agreement with the certified values. The method was applied to the determinations of Zn, Ni and Co in vegetables and foods by FAAS. 相似文献
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The poly(m‐toluidine) film was prepared by using the repeated potential cycling technique in an acidic solution at the surface of carbon paste electrode. Then transition metal ions of Ni(II) were incorporated to the polymer by immersion of the modified electrode in a 0.2 M NiSO4, also the electrochemical characterization of this modified electrode exhibits stable redox behavior of the Ni(III)/Ni(II) couple. The electrocatalytic ability of Ni(II)/poly(m‐toluidine)/modified carbon paste electrode (Ni/PMT/MCPE) was demonstrated by electrocatalytic oxidation of hydrogen peroxide with cyclic voltammetry and chronoamperometry methods in the alkaline solution. The effects of scan rate and hydrogen peroxide concentration on the anodic peak height of hydrogen peroxide oxidation were also investigated. The catalytic oxidation peak current showed two linear ranges with different slopes dependent on the hydrogen peroxide concentration and the lower detection limit was 6.5 μM (S/N=3). The catalytic reaction rate constant, (kh), was calculated 5.5×102 M?1 s?1 by the data of chronoamperometry. This modified electrode has many advantages such as simple preparation procedure, good reproducibility and high catalytic activity toward the hydrogen peroxide oxidation. This method was also applied as a simple method for routine control and can be employed directly without any pretreatment or separation for analysis cosmetics products. 相似文献
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新型镍催化体系合成Cis-1,4聚丁二烯的研究 总被引:1,自引:1,他引:1
本文研究了以加氢汽油为溶剂的Ni(Naph)_2-Al(i-Bu)_2OR-BP_3·OEt_2及Ni(NaPh)_2-Al(i-Bu)_2OAr-BF3·OEt_2两体系对丁二烯的催化聚合活性、聚合物分子量、微观结构等。各种Al(i-Bu)_2OR或Al(i-Bu)_2OAr为助催化剂组成的新型镍催化体系对丁二烯聚合都有较高的催化活性,所得聚合物Cis-1,4含量在96%以上。磁化率和紫外可见光谱研究证明,在Al(i-Bu)_2OR体系中以Ni(Ⅰ)为主及小量未还原的Ni(Ⅱ);Al(i-Bu)_2OAr中Ni(Ⅰ)及Ni(O)共存。 相似文献
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《Journal of Coordination Chemistry》2012,65(1-3):51-64
Abstract The new 1,2-dithiolene, 1,4-butanediyldithioethylene-1,2-dithiolate, has been isolated. In addition, new monoanionic bis-complexes with nickel and copper have been prepared and isolated. The formal Ni(III) complex crystallizes in the orthorombic space group, Pbca, with a = 9.762(9), b = 12.53(2), and c = 23.166(3) Å, with 4 molecules in the unit cell. The structure was refined to an R = 9.01% (Rw = 8.95%). The formal Cu(III) complex crystallizes in the monoclinic space group, C2/c, with a = 25.567(6), b = 8.011(3), c = 14.504(3) Å, and β = 106.17(2)° with 4 molecules in the unit cell. The structure refined to R = 4.2% with R w = 4.3%. Comparisons to similar 1,2-dithiolenes suggest this ligand produces only modest structural and electronic differences when compared to the 1,3-propanediyldithioethylene-1,2-dithiolate complexes. The oxidation (to a neutral complex) and reduction (to a dianion) for the Ni(III) and Cu(III) complexes show large differences from those of maleonitriledithiolate. Other physical data are presented as well. 相似文献
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采用程序升温还原(TPR)、高分辨透射电镜(HRTEM)和X射线光电子能谱(XPS)表征手段对共浸渍法制备的不同磷含量NiMo/γ-Al2O3催化剂进行了表征,研究了磷含量对NiMo/γ-Al2O3催化剂活性相结构的影响。TPR研究表明,磷能够减少四面体配位Mo物种的数量,增加八面体配位Mo物种的数量,促进高活性Ⅱ型"Ni-Mo-S"活性相的形成。HRTEM研究表明,随磷含量的增加,MoS2颗粒堆积层数增加,催化剂的加氢选择性提高;适量磷能够增加边角位有效Mo原子的分散度(fMo),增加催化剂表面加氢脱硫(HDS)和加氢脱氮(HDN)活性位的数量。上述结论得到了XPS表征的证实:适量磷增加了催化剂表面Mo原子浓度、提高有效助剂比率(PR)和提升比率(Ni/Mo),相应催化剂表现出最高的HDS和HDN活性;但过高磷含量能够引起MoS2颗粒过度堆积,片层长度过长,导致活性位数量减少,催化活性降低。 相似文献
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FU Xinliang ZHU Aonan CHEN Xiaojie ZHANG Shifu WANG Mei YUAN Mingjian 《高等学校化学研究》2021,37(6):1328-1333
Electrocatalysis has become an attractive strategy for the artificial reduction of CO2 to high-value chemicals.However,the design and development of highly selective and stable non-noble metal electrocatalysts that convert CO2 to CO are still a challenge.As a new type of two-dimensional carbon material,graphdiyne(GDY),is rarely used to explore the application in carbon dioxide reduction reaction(CO2RR).Therefore,we tried to use GDY as a substrate to stabilize the copper-nickel alloy nanoparticles(NPs)to synthesize Cu/Ni@GDY.Cu/Ni@GDY requires an overpotential(-0.61 V)to 10 mA/cm2 for the formation of CO,and it shows better activity than Au and Ag,achieving a higher Faraday efficiency of about 95.2%and high stability of about 26 h at an overpotential(-0.70 V).The electronic interaction between GDY substrate and Cu/Ni alloy NPs and the large specific surface area of GDY is responsible for the high performance. 相似文献
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lntroductionTheconversi0nofnaturalgast0syngasviQtheCatalyticPartialOxidaion(CPO)ofCH4(Eq.l)lledlethibitsthepotentiaIt0replaceconventionalsteamreforming(Eq.2),withasubstalialreductioninplantsizc.Thisproccssisnotcncrg}intensivc.andalso}'ieldss}.nthesisgasx`.ithH2/COmolarratioof2.O.x`hichissuitabIcforman}'chcmicalproccsscs-suchasthcproductionofmethanoIovcrCu/Zn0catal}'st(Eq.3)andFischcr-Tropschs}nthcsisovcrCo'CucataI}'sts(Eq.4).CO 2H2-CH30H(3)nCO 2nH2-C,,H(2,, l) nH2O(4)Atprcscnt-… 相似文献
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The interaction between nickel and pectin extracted from citrus fruit was studied in 0.10 M KNO3, at pH 5.5 and 25 °C. Differential pulse and/or square wave polarography were used to determine free nickel. For a high coverage degree (θ) of the pectin by the metal ion a good fitting was observed between experimental results and the model that includes both complex species, ML and ML2 (M for the metal ion and L for the ligand). In the ML2 species, Ni(II) interacts with two carboxylate groups of different chains, resulting in an inter-chain association. For low θ values, the formation of ML2 is hindered due to the repulsion between the negative charges of carboxylic groups in two independent segments of pectin. The influence of calcium or copper ions on the free nickel concentration, in the presence of pectin, may lead to a decrease in free nickel concentration, contrary to what would be expected from direct competition between Ca(II) or Cu(II) and Ni(II) for the pectin binding sites. This is due to the partial neutralisation of the negative carboxylic charges by the positive charges of the divalent cations, which favours NiL2 formation through the association of independent chains. 相似文献