共查询到20条相似文献，搜索用时 589 毫秒
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以KMnO4与MnSO4为原料,采用水热法制备了α-MnO2纳米线;采用XRD、IR、SEM、EDS、DTA-TG等对样品的物相、结构、形貌、成分及热稳定性进行了表征;初步研究了反应温度、水热时间及溶剂种类对纳米结构MnO2合成的影响,并探讨了MnO2的晶型转变和-αMnO2纳米线的生长过程。结果表明:①所得α-MnO2纳米线粗细均匀,分散度好,其直径约为50~60 nm;②在水体系中,温度较低和反应时间较短时生成具有层状结构的锰的羟基化合物和-δMnO2,随着反应温度的升高(180~220℃)和水热时间的延长(6~48 h)产物转化为-αMnO2;③将溶剂改为正丙醇,在与②相同的条件下得不到MnO2;④α-MnO2纳米线的生长过程为:MnO4-与Mn2+反应生成MnO(OH),MnO(OH)发生氧化反应生成Mn(OH)4,Mn(OH)4发生脱水反应生成MnO2,产物由无规则球形纳米颗粒最终转化为纳米线。实验中通过控制反应参数达到调控MnO2物相和形貌的目的,为氧化物的可控制备及性能调控提供思路。 相似文献
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制备了γ-MnO2纳米棒以及Au/γ-MnO2催化剂,并用X射线衍射（ XRD）、扫描电镜（ SEM）和透射电镜（ TEM）等手段对其进行表征．结果表明：Au颗粒均匀分散在载体γ-MnO2的表面,颗粒大小约为10 nm．在无溶剂存在下甲苯和氧气的氧化反应中测试了样品的催化活性．研究了反应时间、反应温度、初始氧气压力及催化剂加入量对催化活性的影响．活性测试结果表明：Au/γ-MnO2催化剂对苯甲醛有特殊的选择性;反应时间、温度、初始压力及催化剂加入量等条件对甲苯转化率及苯甲醛、苯甲酸、苯甲酸苄酯的选择性都有很大影响,但对苯甲醇的选择性影响不大． 相似文献
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《实验室研究与探索》2016,(8):138-142
为设计性能更加稳定的电容传声器,介绍了电容传声器的基本组成,讨论了电容传声器薄膜直径的大小、静压均衡孔所处声场中的位置、薄膜张力的大小及薄膜和背极板之间的距离、绝缘体等其它重要组成部分的不同特性对电容传声器性能的影响。以直径为1.27 cm(1/2英寸)的电容传声器为例,通过采用建立更为简单的等效电路模型的方法来完成其设计,并通过所建立的等效电路模型及相对应的各参量数据得出了电容传声器的幅频响应曲线和相频响应曲线,证实了该等效电路的正确性和可行性。通过上述讨论及实验对电容传声器在设计中的工艺要点提供了新的思考方向,也为电容传声器的设计提供了新的思路。 相似文献
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二氧化锰（MnO2）价格低廉、环境友好,具有优良的离子交换、分子吸附、电化学、催化和磁学性能,大量用于电池等工业,是一种重要的无机功能材料。二氧化锰的晶型种类繁多,已发现5种主晶型和30余种次晶型,其中以a-Mn02、β—Mn02、y-Mn02、δ-Mn02、λ-MnO2五种主晶型为代表。一般认为,材料的晶体结构与其性能有直接的关联,因此,合成不同晶型及不同形貌的二氧化锰材料很有意义,传统的二氧化锰制备工艺对锰矿利用率低,且制备出的二氧化锰在性能方面远远无法满足现代材料的需求,大大限制了二氧化锰的应用。由于纳米材料特殊的表面效应、小尺寸效应、量子尺寸效应和宏观量子隧道效应等,使得纳米二氧化锰的制备成为研究热点。 相似文献
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目的:合成3D C-Ni3Si2O5(OH)4电极材料,并对此合成材料的物理性质进行探究,通过电化学测试从中选出电化学性能最优的合成方法.方法:以煅烧天然芦苇叶得到的碳源(C-SiO2)结合Ni(CH3COO)2·4H2O,形成层状硅酸镍C-Ni3Si2O5(OH)4纳米颗粒作为电极材料,需要将其按照不同比例进行混合,将其编号为C-NiSi-1-5,并采用X射线衍射(XRD)、扫描电子显微镜(SEM)、红外光谱和电化学测试等方法研究复此合材料的结构、形貌及超级电容性能.结果:测试结果表明,与C-SiO2结合并原位生成的层状硅酸镍具有较高的比表面积、多孔结构和出色的电化学性能.结论:编号为C-NiSi-3的电极材料在0.5 A/g电流密度下比电容为74.7 F/g,C-NiSi-3在10000次循环后具有97％ 的出色电容保持率. 相似文献
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如图1,一个未经充电的理想电容,电容量为C,在t≥0时与理想电压源接通,根据电路知识：i（t）=C du/dt=CUδ（t）,稳定后,电容器最终储能：WC=∫0^Q udq=∫0^Q q/C dq=1/2 Q^2/C=1/2CU^2,整个过程中,电源提供能量： 相似文献
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本文通过测量Co3Ti、 Ni3Al、 Fe3Al、 TiAl四种金属间化合物在氧气、氢气中在2×10-4/s形变速率下的拉伸性能，研究了
其在氢气中的室温环境脆性.研究结果表明，上述四利金属间化合物在H2中的脆化程度(用氢脆因子
IH2=[(δo2一δH2)/δo2]×100％表示)是不同的，其大小依次为Co3Ti＞Ni3 Al＞Fe3Al＞TiAl.其脆化程度的差异用金属间化合物中
基体金属对氢气的催化裂解作用的强弱进行了很好的解释. 相似文献
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本文主要处理非局部波动方程组解的全局存在与爆破问题,考虑如下非局部波动方程组的初值问题：{δ^2u1/δt^2=δ^2u1/δx^2＋‖u2（·,t）‖p1,δ^2u2/δt^2＋‖u3（·,t）‖p2,δ^2u3/δt^2=δ^2u3/δx^2＋‖u1（·,t）‖p3,-∞〈x〈∞,t〉0 ui（x,0）=fi（x）,δui/δt（x,0）=gi（x）,i=1,2,3,-∞〈x〈∞ 这里0〈p1,p2,p3〈＋∞,‖ui（·,t）‖=∫-∞^＋∞ φi（x）｜u（x,t）｜dx,i=1,2,3,其中φi（x）≥∫-∞^＋∞ φi（x）dx=1,i=1,2,3。所有这些初值函数都为连续的且｜fi（x）｜＋｜gi（x）｜恒不等于0,i=1,2,3.根据对称性,本文假定p1≤p2≤p3. 相似文献
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Potassium-ion batteries (KIBs) are considered the next powerful potential generation energy storage system because of substantial potassium resource availability and similar characteristics with lithium. Unfortunately, the actual application of KIBs is inferior to that of lithium-ion batteries (LIBs), in which the finite energy density, ordinary circular life, and underdeveloped fabrication technique dominate the key constraints. Various works have recently been directed to growing novel anode electrodes with superior electrochemical capability. Noticeably, metals/metal oxides materials (e.g., Sb, Sn, Zn, SnO2, and MoO2) have been widely investigated as KIBs anodes because of high theoretical capacity, suggesting outstanding promise for high-energy KIBs. In this review, the latest research of metals/metal oxides electrodes for potassium storage is summarized. The major strategies to control the electrochemical property of metals/metal oxides electrodes are discussed. Finally, the future investigation foreground for these anode electrodes has been proposed.
相似文献12.
In this study, a bulk composite material symbolized as NiCo LDH-rGO/Ni F was developed by a solvothermal process for the first time. This material was fabricated through simultaneous growth of nickel-cobalt layered double hydroxide(NiCo LDH) and reduced graphene oxide(rGO) on nickel foam. This bulk composite can be used directly as a binder-free electrode for supercapacitors(SCs). The physicochemical properties of this composite were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The electrochemical properties of the composite were measured by the cyclic voltammetry and galvanostatic charge-discharge. The results show that this composite had a hierarchical structure and exhibited a significantly enhanced specific capacitance of up to 3383 F/g at 1 A/g. The asymmetric SC using this composite as a positive electrode had a high energy density of 40.54 Wh/kg at the power density of 206.5 W/kg and good cycling stability. Owing to the synergies between the metal oxides and the rGO, the preparation method of in situ growth and its hierarchical structure, this bulk composite displayed excellent electrochemical performance and had a promising application as an efficient electrode for high-performance SCs. 相似文献
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Natural and Treated FeS2 in Li/FeS2 Coin Cell 总被引：1，自引：0，他引：1
TREATED FES, SAMPLES WERE PREPARED BY NATURAL FES, SAMPLES WHICH WERE GROUND FIRST, HEATED IN NITROGEN AND THEN WASHED IN ACID. THE LEVELS OF IMPURITY ELEMENTS, PRIMARILY PRESENT AS METALLIC OXIDES AND SULFIDES, ARE HIGHER IN THE NATURAL FES, THAN THOSE IN THE TREATED SAMPLE. SCANNING ELECTRON MICROSCOPY SHOWS THAT THE GRAIN SIZES OF TREATED FES, PARTICLES ARE SMALLER THAN THOSE OF NATURAL FES, PARTICLES. THE ELECTROCHEMICAL PERFORMANCE OF LI/TREATED FES, CELLS IS ATTRIBUTED TO THE SMALLER GRAIN SIZES AND HIGHER PURITY OF TREATED FES, PARTICLES IN COMPARISON TO THE NATURAL FES, SAMPLE. 相似文献
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A specialised electrochemical measurement cell was plugged into a pilot water distribution system to simulate the pipe inner-wall corrosion. The linear polarisation resistance(LPR) technique and electrochemical impedance spectroscopy(EIS) were measured in real time to study the variation of the corrosion rate(CR) and scale of cast iron. Three corrosion stages were observed according to the LPR analysis: an initial stage with significantly fluctuating CR, a developmental stage with slowly decreasing CR, and a stable stage with a low CR of approximately 0.157 5 mm·a~(-1). The EIS revealed that the scales with a compact outer layer and a porous inner layer finally formed in the stable stage, and the polarisation resistance was approximately 2 175 ?·cm~2. A physicochemical analysis of the scales showed that ferric oxides, oxyhydroxides and calcite made the outer layer compact and effectively limited the diffusion of oxygen through the scales, which resulted in a low CR. 相似文献
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刘雪华林伟明商川杨斯盛 《福建工程学院学报》2020,(3):241-245
结合溶胶-凝胶法和化学镀方法,于镁合金基材表面成功制备了均匀的复合Ni-P-SiO_2/TiO_2/Al_2O_3镀层,采用扫描电镜(SEM)、光学显微镜(OM)、摩擦磨损试验及电化学方法,对比研究了Mg基材、基础Ni-P镀层与3种复合镀层的显微组织结构、耐磨性及耐腐蚀性。结果表明,加入3种溶胶所制备的复合镀层较Mg基材大幅度提高耐磨性和耐腐蚀性;3种复合镀层较Ni-P镀层具有更加均匀、致密的显微形貌,减少了直接加入纳米粉末的团聚,同时耐磨和耐蚀性改善。其中Ni-P-SiO_2复合镀层具有较高的显微硬度(HV513)和最低的摩擦系数(0.34),最高的腐蚀电位(-1.18V)及较小的腐蚀电流密度(9.5×10~(-3)mA·cm~(-2))。综合制备最佳工艺,并考虑节能减排因素,Ni-P-SiO_2复合镀层可作为性能优良的Mg合金耐磨、耐腐蚀镀层使用,于实际工业生产大有裨益。 相似文献
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采用热分解法制备RuO2-TiO2-SnO2/Ti氧化物涂层,探究不同涂覆层数对涂层性能的影响。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、能谱仪(EDS)对涂层的组织结构进行分析;采用极化曲线、循环伏安曲线和强化电解寿命等对阳极的电化学性能进行评价。结果表明:涂层样品主要由RuO2、TiO2、SnO2金红石相固溶体相组成。不同涂覆层数阳极的电化学性能不一样,涂覆层数为12的样品涂层的综合性能最好。 相似文献
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制备了在可见光照射下具有较高催化活性的系列TiO2/Cu2O光催化剂,并用其在可见光下光催化降解酸性大红.研究了TiO2含量和H2O2对光催化反应的影响.结果表明5%TiO2/Cu2O的光催化活性曩好,在加入少量的H2O2情况下酸性大红的脱色率可达到86%,化学需氧量(CODcr)去除率达到65%. 相似文献
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采用陶瓷薄膜技术及溶胶一凝胶法制备了氧离子传导YSZ（Y2O3稳定的ZrO2）电解膜与电极催化剂,构建了膜电极组装（MEA）及结构为H2S、（复合MoS2阳极）／YSZ传导膜／（复合NiO阴极）、空气燃料电池系统;通过在MoS2中掺杂NiS、电解质、Ag粉和淀粉制备了双金属复合MoS2阳极催化剂,在NiO中添加电解质、Ag粉和淀粉制备了复合NiO阴极催化剂：考察了不同操作温度对电池性能的影响,比较了几种不同电极催化剂的性能,研究了H2S／air固体氧化物燃料电池的电化学性能。实验结果表明,在H2S环境中,复合MoS2阳极催化剂比MoS2和Pt具有更好的性能,复合Nio阴极Pt阴极的极化小;在电极催化剂中加入Ag可显著提高电极的导电性．添加电解质和淀粉可以提高电极的离子传导性和多孔性：操作温度增加．传导膜的电传导率和电化学反应速率增加,电池的输出电流与功率密度增加,电化学性能变好。电池连续运行1～4d几乎不降级。在850℃和101．13kPa时．燃料电池最大输出功率密度为155mW·cm^-2,对应的电流密度为240mA·cm^-2。 相似文献
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Xue-ying QIN Jing-lun WANG Dao-ping TANG Yong-jin MAI Ling-zhi ZHANG 《浙江大学学报(A卷英文版)》2013,14(7):514-519
{3-[2-(2-methoxyethoxy) ethoxy]-propyl} triethoxysilane (TESM2) was synthesized and used as an electrolyte additive to improve the performances of lithium-ion batteries (LIBs). The electrochemical properties of the electrolyte (1 mol/L lithium hexafluorophosphate (LiPF6)/ethylene carbonate (EC):diethylene carbonate (DEC):dimethyl carbonate (DMC), 1:1:1) with different contents of TESM2 were characterized by ionic conductivity measurement, galvanostatic charge/discharge test of graphite/Li half cells, and electrochemical impedance spectroscopy. Both the cycling performances and C-rate capabilities of graphite/Li half cells were significantly improved with an optimized content of 15% TESM2 in the electrolyte. The graphite/Li half cell delivered a very high specific capacity of 370 mAh/g at 0.2C rate without any capacity loss for 60 cycles, and retained a capacity of 292 mAh/g at 2C rate. The solid electrolyte interphase (SEI) film on the surface of the graphite anode was investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), indicating that TESM2 was effectively involved in the formation of SEI film on the surface of graphite. 相似文献