共查询到19条相似文献,搜索用时 156 毫秒
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以烧结后的La2O3、CeO2、NiO混合物片体作为阴极,高密度碳棒作为阳极,在850℃的CaCl2熔盐中,采用恒电压电解,对La0.5Ce0.5Ni5三元合金进行了制备。用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对样品的分析结果表明,经1050℃烧结的混合氧化物,在3.1V工作电压下电解12h,可以得到海绵状La0.5Ce0.5Ni5三元储氢合金。不同时间电解后样品的XRD衍射图谱显示,电解过程是逐步进行的,NiO首先在电极上还原为Ni,然后LaOCl(由La2O3与CaCl2反应生成)和CeOCl(由部分还原的CeO2与CaCl2反应生成)在新生成的Ni表面还原并形成La0.5Ce0.5Ni5合金。Ni单质的存在很可能是由于生成的LaOCl和CeOCl部分溶解在熔盐中造成损失,使得Ni量多于化学计量比。 相似文献
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以钛酸四正丁酯((C4H9O)4Ti)水解沉淀的钛羟基氧化物和硝酸钙(Ca(NO3)2.4H2O)为反应物料,加入适宜浓度的矿化剂氢氧化钾和络合剂柠檬酸钠,在温度200℃水热反应12h后得到了CaTiO3粉体。利用SEM、XRD、TEM等对CaTiO3的形貌、尺寸和结构进行表征,通过光催化降解罗丹明B(RhB)对其紫外光催化性能进行了研究。结果表明柠檬酸钠在CaTiO3水热合成过程中起到关键性作用,其形貌和紫外光催化性能随着柠檬酸钠浓度改变而发生巨大变化。 相似文献
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通过对TiO_2碳热还原进行热力学计算,得出真空碳热还原技术能降低反应温度。采用X射线衍射以及电阻测量装置考察了TiO_2真空碳热还原过程,并将最终还原产物制备成可溶性TiO阳极进行电解。结果表明:在还原温度为1200℃,还原时间2 h,TiO_2与碳摩尔比为1:3的条件下,可以得到电阻率较低(小于0.03Ω·m)的低价氧化钛。整个还原过程TiO_2遵循逐级还原理论,反应产物会经历TiO_2→Ti_6O_(11)→Ti_4O_7→Ti_3O_5→Ti_2O_3→TiO的还原过程。最终将还原产物TiO与C混合制备成阳极,石墨为阴极时,850℃在CaCl_2-KCl熔盐体系中电解2 h后可生成TiC;相同实验条件下,TiO与C按配比压制成阳极,铁为阴极,中间以泡沫陶瓷材料相隔,产物则为金属钛及钛铁合金。 相似文献
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以CaCO3和TiO2为原料,焙烧温度为1500℃,焙烧时间分别为2、4、6、8、10h的条件下焙烧得到CaTiO3。应用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外变换光谱仪(FT-IR)、紫外-可见光漫反射光谱仪(UV-Vis)对焙烧后的物料进行了表征。实验结果表明,焙烧时间对合成CaTiO3的纯度影响很小;焙烧时间的延长使得CaTiO3微观形貌从不规则多边形向光滑曲面形变化,颗粒团聚现象越来越明显,堆积密实,尺寸增大;焙烧时间对钛酸钙光吸收能力的影响很小。在光催化性能评价实验中,随着焙烧时间的延长,亚甲基蓝的降解率和降解速率降低,反应速率常数最多可降低接近50%;钛酸钙降解亚甲基蓝溶液比较符合一级反应动力学特征。 相似文献
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采用Na_3AlF_6-AlF_3-LiF-MgF_2为基础电解质,Al_2O_3-CuO-Y_2O_3为原料的氟盐-氧化物体系熔盐电解制取Al-Cu-Y合金。重点通过循环伏安分析Y(Ⅲ)在阴极的电极还原过程,利用扫描电镜(SEM)及能谱(EDS)表征并对比分析热还原产物及电解产物的成分及物相组成。结果表明:AlF_3-NaF-5%LiF-5%MgF_2(质量分数,下同)(n(NaF)/n(AlF_3)=2.2)体系在温度1 208K、电压3.0V、阴极电流密度0.7A/cm~2、电解时间2h条件下能够制取Al-Cu-Y合金。Cu(Ⅱ)在碳质电极表面可一步直接还原为零价态Cu(0);Y(Ⅲ)不能在体系内直接还原为零价态Y,而是在预先形成的Al-Cu活性阴极表面还原并合金化,从而形成强化相Al_3Y,并与Al_2Cu强化相同时富集于铝基体相晶界。通过在熔盐底部的液态铝热还原CuO及Y_2O_3也可形成Al-Cu-Y合金,但铝基体相晶界富集AlCu相及AlY相,Cu及Y含量不易控制,且存在较多O、C杂质元素。 相似文献
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熔盐电脱氧制多晶硅过程电流效率的影响因素 总被引:2,自引:0,他引:2
电流效率是熔盐直接电解脱氧制备多晶硅的一项重要指标,它涉及到电解槽的产量和电耗.如何提高熔盐电解的电流效率对多晶硅的单位时间产量、降低单位电耗等具有重要意义.采用CaCl2为电解质、SiO2粉末压制片为阴极及自制石墨棒为阳极进行了实验研究.在具体实验中测定了制备多晶硅过程中电流效率随电解时间、温度、电流密度及电极间距的变化关系.结果表明,当电解时间为6~10h、电解温度为800~900℃、电流密度为0.78~1.20A/cm2、电极间距为4~7cm时,电解效率较高. 相似文献
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Houfu Lv Le Lin Xiaomin Zhang Yuefeng Song Hiroaki Matsumoto Chaobin Zeng Na Ta Wei Liu Dunfeng Gao Guoxiong Wang Xinhe Bao 《Advanced materials (Deerfield Beach, Fla.)》2020,32(6):1906193
Reversible exsolution and dissolution of metal nanoparticles in perovskite has been investigated as an efficient strategy to improve CO2 electrolysis performance. However, fundamental understanding with regard to the reversible exsolution and dissolution of metal nanoparticles in perovskite is still scarce. Herein, in situ exsolution and dissolution of CoFe alloy nanoparticles in Co-doped Sr2Fe1.5Mo0.5O6–δ (SFMC) revealed by in situ X-ray diffraction, scanning transmission electron microscopy, environmental scanning electron microscopy, and density functional theory calculations are reported. Under a reducing atmosphere, facile exsolution of Co promotes reduction of the Fe cation to generate CoFe alloy nanoparticles in SFMC, accompanied by structure transformation from double perovskite to layered perovskite at 800 °C. Under an oxidizing atmosphere, spherical CoFe alloy nanoparticles are first oxidized to flat CoFeOx nanosheets, and then dissolved into the bulk with structure evolution from layered perovskite back to double perovskite. Electrochemically, CO2 electrolysis performance can be retrieved during 12 redox cycles due to the regenerative ability of the CoFe alloy nanoparticles. The anchoring of the CoFe alloy nanoparticles in SFMC perovskite via reduction shows enhanced CO2 electrolysis performance and stability compared with the parent SFMC perovskite. 相似文献
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Yiwen Ren Shaolong Li Zepeng Lv Yong Fan Jilin He Jianxun Song 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(23):2207863
The application of carbides in catalysis, batteries, aerospace fields, etc. has been continuously expanded and deepened, which is attributed to the diversified physicochemical properties of carbides via a tune-up of their morphology, composition, and microstructure. The emergence of MAX phases and high entropy carbides with unparalleled application potential undoubtedly further stimulates the research upsurge of carbides. The traditional pyrometallurgical or hydrometallurgical synthesis of carbides inevitably faces the shortcomings of complex process, unacceptable energy consumption, extreme environmental pollution, and beyond. The molten salt electrolysis synthesis method with the superiorities of straightforward route, high efficiency, and environmental friendliness has demonstrated its validity in the synthesis of various carbides, which naturally initiates more research. In particular, the process can achieve CO2 capture while synthesizing carbides based on the excellent CO2 capture capability of some molten salts, which is of great significance for carbon neutralization. In this paper, the synthesis mechanism of carbide by molten salt electrolysis, the process of CO2 capture and carbides conversion, the latest research progress in the synthesis of binary, ternary, multi-component, and composite carbides are reviewed. Finally, the challenges, development perspectives, and research directions of electrolysis synthesis of carbides in molten salts are featured. 相似文献
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熔盐电解法制备海绵钛工艺中TiO2电极制备关键技术分析 总被引:5,自引:1,他引:4
熔盐电解法制备海绵钛所用电极,既是电的传导体,又是产品的来源。在电极的制备过程中,既要保证电流的顺畅导通,又要满足熔盐渗入电极中的工艺要求,如何解决这两者之间的矛盾,是关系着该工艺能否有效实施的关键。本文对上述问题进行了探索,通过理论分析及进行各种温度下电极的电阻系数、孔隙率的实验测定,找出制备电极的较好工艺。并应用该优化工艺后的电极进行了电解实验,产品含钛量达到99.5%以上,结合试验结果对电源设备进行了改进,电解电流已达到了40安培以上,在工艺上实现了较大的突破。 相似文献
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Hongwei Xie) He Zhang) Yuchun Zhai) Jinxia Wang) Chengde Li) ) School of Materials Metallurgy Northeastern University Shenyang China ) School of Science China 《材料科学技术学报》2009,25(4)
Al was prepared by a new method in molten salt at low temperature.Sintered alumina pellets were used as cathode;graphite rod was employed as anode;and the molten CaCl2-NaCl was the electrolyte.A constant 3.2 V voltage was applied in this experiment,and oxygen in solid alumina cathode was reduced by direct electrochemical deoxidation at 550℃.In this process,the current gradually decreased with increasing time and the alumina pellets became grey and porous.The metallic particles were obtained and characterize... 相似文献