共查询到18条相似文献,搜索用时 93 毫秒
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采用液相化学还原法,以硫酸铜为原料,抗坏血酸作还原剂,吐温-80作修饰剂,用正交实验方法获得了油溶性纳米铜的最佳的合成条件:抗坏血酸为3 g,吐温-80为30 mL,正丁醇为70 mL,反应温度95℃。并利用X射线衍射仪对产品进行表征测试。 相似文献
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纳米镍粉的固相合成及其催化活性研究 总被引:1,自引:1,他引:1
介绍了以NiSO4·6H2O和NaOH为原料,固相法合成镍纳米粉。通过XRD、TEM、SEM和XPS等测试手段对产物表面结构进行表征。结果表明,产物为球形分布均匀的纳米镍粉,平均粒径为(30±5) nm。同时考察了不同还原温度和时间下得到的产物的催化活性以及反应中温度、压力和含量等对硝基苯加氢还原催化活性的影响,并在相同的条件下,和Raney Ni进行比较。还原实验表明,400 ℃还原4 h的产物质量分数为4.13%时,硝基苯转化率高达26.26%,催化加氢活性高于Raney Ni,是相同条件下Raney Ni的9倍左右。压力为0.8 kPa时,硝基苯转化率高达76.42%。 相似文献
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以羰基镍粉为原料,采用焙烧法制备了氧化亚镍,并将其球磨后得到微米粉体。采用热重-差示扫描量热仪(TG-DSC)研究了羰基镍粉在空气气氛中加热时的氧化行为,利用激光粒度分析仪、等离子体光谱仪、X射线衍射仪(XRD)和扫描电镜(SEM)等分析了样品结构、成分和形貌。结果表明:空气和氧气两种气氛对产物纯度影响不明显。在两种载气条件下,通过优化焙烧温度和焙烧时间(焙烧温度为700 ℃、焙烧时间为2 h、载气流量为1.5 L/min),羰基镍粉可直接焙烧制备得到纯度为100%、结晶度高的面心立方体氧化亚镍,球磨后得到粒度为4~19 μm的类球形微米氧化亚镍粉末。制备过程具有工艺简单、环境友好的特点。 相似文献
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Jiang Wu Guanqi Wang Qizhen Liu Yang Ling Ruitao Zhang Ningchao Sun Yingchao Gao Zhihao Chen Yijing Sun Yunfei Gao 《加拿大化工杂志》2023,101(8):4640-4647
In many photocatalytic reaction paths, the breaking of the first C O bond in a CO2 molecule is often the key step that becomes the rate-controlled reaction step. In this paper, a graphitic carbon nitride (g-C3N4) supported nickel single-atom catalyst (Ni@g-C3N4) was successfully constructed, and the mechanism of CO2 catalytic reduction was systematically studied based on density functional theory (DFT). The introduction of nickel promotes the adsorption of small molecules, especially for the CO2 activation. According to density of states (DOS) and frontier orbital analysis, the photogenerated carriers tend to jump from nitrogen atoms to carbon atoms, forming an electron transfer in real space, after g-C3N4 is excited by light. With the appearance of nickel-doped levels, the DOS of Ni@g-C3N4 is no longer symmetric with respect to the spin up and down, especially around the original band gap of g-C3N4. Single-atom nickel has abundant frontier orbitals and high activity and is a favourable place for chemical reactions. The presence of surface hydrogen can promote the recovery of CO2, and the energy barrier of Ni@g-C3N4 with hydrogen is only 15% of the clean g-C3N4 surface. This paper provides a new idea for the development of efficient single-atom catalysts for CO2 reduction. 相似文献
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Chen-Bin Wang Guo-Yuan Gau Shiue-Jiun Gau Chih-Wei Tang Jia-Lin Bi 《Catalysis Letters》2005,101(3-4):241-247
Nanosized nickel oxide was synthesized by a simple liquid-phase process to obtain the hydroxide precursor and then calcined to form the oxide. The precursor and the nickel oxide were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), thermal analysis (TG) and temperature-programmed reduction (TPR). The results indicated that the particle size of nickel oxide was controlled by the calcined temperature (TC). Mixed phases of nickel oxide and nickel hydroxide were present as the TC was lower than 300 °C. Non-stoichiometric nickel oxide (NiOx, x = 1.2) was formed between 250 °C and 400 °C and a pure nickel oxide was formed as the TC arrived 500 °C. The particle size of nickel oxide changed as the calcined temperature was controlled under 250 °C, 300 °C, 400 °C and 500 °C, the order was 5.6 nm, 6.5 nm, 11 nm and 17 nm, respectively. 相似文献
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针对硫酸镍液相通氢还原制得球状超细镍粉品位较低(仅在96%左右)的问题,提出一条通过火法-湿法联合还原提高镍粉品位的工艺路线。首先由硫酸镍和氢氧化钠水溶液在室温下混合而成氢氧化镍浆料,不经过过滤洗涤,转入高压釜进行悬浮态氢还原。反应结束后,液固分离,获得品位在96%左右的半成品镍粉。将半成品镍粉在氢还原炉中进行二次还原,控制还原温度为400 ℃,还原时间为2 h,获得的产品镍质量分数大于99.5%,粒度小于2.0 μm,满足金刚石工具、硬质合金等行业需求的超细镍粉性能指标要求。 相似文献
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