高氧超电极在电解法生产氯酸盐中的应用

制备了３种氧化涂层电极,分析了涂层物相组成、涂层形貌,测定了电极的电化学性能,研究了这些电极在电解法生产氯酸盐中的应用。结果表明：钌锡锑氧化物涂层电极具有较低析氯电位、较高析氧电位,电解ＮａＣｌ溶液生产ＮａＣｌＯ３具有较高电流效率。     

镍掺杂钨氧化物电极制备及对苯酚的催化降解研究

通过阴极电沉积在钛基体上制备了掺杂Ni元素的WOX涂层电极,采用XRD、EDS分析认为涂层主要是四价钨的氧化物及镍氧化物的混合物。循环伏安测试苯酚在电极上的氧化电位为0.556 V,电极具有很好的电化学催化氧化活性。电极对苯酚的电化学氧化降解效果较好,苯酚的去除率接近90%,COD的去除率在43%左右,提高了苯酚模拟废水的可生化性。     

换向脉冲电沉积法制备Ti/TNTs/Sb–SnO_2阳极及其性能研究

以Ti阳极氧化所得TiO_2纳米管(TNTs)为基体,采用换向脉冲电沉积制备Sb掺杂SnO_2电极(Ti/TNTs/Sb–SnO_2)。采用X射线衍射、扫描电镜、能谱等手段对其微观结构、表面形貌及元素组成进行分析,研究了它作为阳极对对硝基苯酚(p-NP)的电催化氧化降解能力。结果表明,当负向脉冲电流为60 m A时,换向脉冲电沉积法制备的Ti/TNTs/Sb–SnO_2电极的表面覆盖层均匀,致密,无裂缝。阳极极化曲线的分析结果表明,该电极的析氧电位为2.28 V,用其降解对硝基苯酚2.5 h后,去除效率达81%。     

钛基二氧化铅电极电催化降解2-氯苯酚

用热解法和电沉积法分别制备了Ti/β-PbO2、Ti/SnO2+Sb2O3/β-PbO2和Ti/α-PbO2/β-PbO2 3种电极,并采用电子扫描电镜、X-射线衍射仪和阳极极化曲线分别对所制备的电极进行了表征,并以2-氯苯酚为目标污染物,考察了3种电极的电催化氧化性能和电极使用寿命.结果表明,中间层对表面活性层的结构形貌和催化活性都有很大影响,其中Ti/α-PbO2/β-PbO2电极析氧电位最高,对2-氯苯酚的去除率可达99.3%,且具有较长的电极使用寿命和较低的槽电压;3种电极对2-氯苯酚降解反应均遵循1级反应动力学规律.     

TNTs/IrO_2-Ta_2O_5-SnO_2-Sb_2O_5-MnO_2电极的制备与性能研究

采用阳极氧化-热分解法在螺旋钛丝上生长出二氧化钛纳米阵列管(TNTs),然后采用热分解法在钛基上制备了TNTs修饰的不同涂层摩尔浓度的TNTs/IrO_2-Ta_2O_5-SnO_2-Sb_2O_5-MnO_2电极。运用SEM、EDS、XRD、CV和等方法去该系列电极进行物理和电化学表征,同时采用强化寿命测试对其进行稳定性表征。结果表明:钛电极表面有排列均匀紧凑的TiO_2纳米管生成,并与活性组分形成固溶体,有利于增强了活性涂层的结合力。涂层浓度为IrTaSnSbMn_2的TNTs/IrO_2-Ta_2O_5-SnO_2-Sb_2O_5-MnO_2阳极具有较高的电化学稳定性、表面活性和孔隙率和较长的使用寿命。电极失效分析表明,该电极失效的主要原因为活性物质的溶解和活性涂层的剥落。     

Ti/BDD涂层电极的制备及其电化学性能研究

本文在热丝化学气相沉积(HFCVD)系统上,采用不同的工艺参数进行了钛衬底掺硼金刚石(Ti/BDD)涂层电极的制备试验,研究了衬底温度和碳源浓度对Ti/BDD涂层电极质量的影响,优化了制备Ti/BDD涂层电极的工艺条件.结果表明,沉积Ti/BDD涂层电极最合适的衬底温度为770 ℃,最适宜的C/H为2.0%.采用循环伏安法研究了用优化的工艺参数制备的Ti/BDD涂层电极的电化学性能,结果表明Ti/BDD涂层电势窗口宽、析氧电位高、背景电流小,是一种有广阔应用前景的电极材料.     

Fe~(3+)、Ce~(3+)掺杂SnO_2/C/Ti催化电极上苯酚的电化学行为研究

采用溶胶-凝胶法合成Fe3+、Ce3+掺杂SnO2/C胶体,通过Vulcan XC-72炭黑负载制备炭载锡系氧化物电催化剂。经X射线粉末衍射(XRD)考察了催化电极的元素组成,利用循环伏安法(CV)研究苯酚在电极上的氧化降解,考察了不同的掺杂元素、不同的掺杂量、制备工艺等因素对电极催化性能的影响。结果表明:所合成的电催化剂中的金属氧化物的主要相态为金红石型SnO2;Sn系列氧化物电极对苯酚具有一定的催化能力,适量Sb、Ce、V、Yb元素的掺杂有利于电极电化学性能的提高,Sb(2.5%)和Ce(2.5%)双掺的SnO2/C/Ti电极的氧化峰电流最大,苯酚在电极表面氧化时,均会产生一层疏松的钝化膜,苯酚仍可以穿透这层钝化膜继续在电极上氧化。     

钛基IrO2+SnO2电极的析氧性能及其在电合成丁二酸中的应用

通过热分解法制备了IrO2+ SnO2/Sb2 O3+ SnO2/Ti、IrO2+ SnO2/Ti、IrO2+ Ta2O5/Sb2O3+ SnO2/Ti电极,通过线性伏安、电化学阻抗、强化寿命测试等研究了钛基涂层电极在1 mol· L-1硫酸溶液中的析氧性能.采用EDX、SEM等考察了电极的表面元素分布和电极强化寿命测...     

PbO2电极氧化有机废水的研究

采用电沉积法制备PbO2电极及其复合电极,并以其为阳极对含酸性红B的模拟染料废水进行处理。结果表明Co-Bi-PbO2/Ti电极兼有较高的催化效果和较长的使用寿命,是今后研究和发展的重点。极化曲线的研究表明,Co-Bi-PbO2/Ti电极的析氧电位约在2.1Vvs.RE(RE:SO42-Hg2SO4Hg),明显高于石墨和Sn-SbOx/Ti电极,有较高的析氧过电位,这也正是Co-Bi-PbO2/Ti氧化有机物能力强的原因。     

Ti/CeO_2-PTFE-PbO_2电极的制备及其电催化氧化性能

采用热分解-电镀法制备了聚四氟乙烯(PTFE)掺杂PbO2电极(Ti/PTFE-PbO2)和PTFE、CeO2共掺杂PbO2电极(Ti/CeO2-PTFE-PbO2),考察了电流密度、温度、搅拌速率、CeO2浓度等工艺条件对电极寿命的影响。对Ti/CeO2-PTFE-PbO2的电催化氧化性能进行了初步研究。结果表明,在电流密度为30mA.cm-2、温度80℃、搅拌速率为1300r.min-1和CeO2为3g.L-1等较优条件下,Ti/CeO2-PTFE-PbO2电极在9mol.L-1H2SO4溶液中的强化电解寿命(1A.cm-2)达983h。SEM和EDX的分析结果表明,PTFE、CeO2共掺杂使得Ti/CeO2-PTFE-PbO2表面的晶粒排布更均匀致密,电解过程镀层的铅氧计量比也具有较高的稳定性。由于具有更高的析氧电位,与Ti/PTFE-PbO2电极相比,Ti/CeO2-PTFE-PbO2电极对对氯苯酚的降解显示了更好的电催化活性。     

Electrochemical characteristics of hydrogen storage alloys modified by electroless nickel coatings

Multicomponent hydrogen storage alloy with the composition MmNi_3.31Mn_0.37Al_0.28CO_0.64 (Mm = misch metal consisting of 24.87% La, 52.56% Ce, 5.57% Pr, 16.86% Nd and 0.14% Sm) was used as a negative electrode material. To improve the performance of the negative electrode, the alloy particles were modified with various electroless Ni-P and Ni-B coatings. Electrochemical properties such as discharge capacity and high-rate dischargeability of the negative electrode were generally improved by the surface modifications. However, in the case of a Ni-P (10 wt % P) coating, the discharge capacity and high-rate dischargeability decreased with increasing thickness, due to the low hydrogen permeability and high electric resistivity of the coating. Consequently, both kinds of coating and their thickness are critical factors in determining the performance of such a negative electrode.     

七种稀土元素对酸性化学镀镍-磷合金镀层影响

在酸性化学镀镍镀液中分别加入Ce、La、Y、Sm、Sc、Lu和Tm七种稀土元素,对基材进行化学镀镍,探究稀土元素对沉积速率、镀层孔隙率及表面形貌的影响.结果证明,七种稀土元素对沉积速率以及镀层性能影响各不相同.其中,Ce、Y和Lu三种稀土元素在一定质量浓度范围内有加速作用,加入4 mg/L Ce的加速比最大,为18.05％.七种稀土元素对镀层孔隙率均有抑制作用,最低能达到0.32个/cm2.     

梯度电流密度下电沉积制备铜-镍-钼合金电极及其性能研究

采用梯度电沉积法制备铜基Cu–Ni–Mo合金电极,电流密度参数为:10 mA/cm^2×5 min+30 mA/cm^2×40 min+50 mA/cm^2×5 min。通过扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)和X射线光电子能谱仪(XPS)分析了Cu–Ni–Mo合金镀层的表面形貌、元素组成、相结构和各元素的化学价态,并通过线性扫描伏安曲线(LSV)、电化学阻抗谱(EIS)和计时电流法对比了Cu–Ni和Cu–Ni–Mo合金电极在1 mol/L KOH溶液中的析氢性能和稳定性。结果表明,所得Cu–Ni–Mo合金镀层是呈花椰菜多孔形貌的非晶态结构。与Cu–Ni合金电极相比,Cu–Ni–Mo合金电极具有更大的比表面积,可为析氢反应提供更多活性位点,表现出更好的析氢性能,稳定性也更好。     

Cylindrical Al2O3 /TZP functionally graded materials by EPD

Abstract

Cylindrical Al₂O₃/Ce–TZP functionally graded com posites were fabricated by electrophoretic deposition and pressureless sintering in air. Negatively charged Ce–TZP and Al₂O₃ powders were deposited on a cylindrical electrode from an acetone based suspension. A continuous composition change is realised by chang ing the composition of the suspension. Sintering of the FGM at different temperatures, showed that a temper ature higher than 1550°C was necessary for densification. The resultant FGM cylinder with 5·6 mm dia. had an ideal mechanical structure: a central open channel, a tough Ce–ZrO₂ core (K_Ic > 10 MPa m^1/2), a continuous gradient interlayer, and a hard surface layer with HV higher than 15 GPa.     

基于Ti/SnO2阳极的电化学法降解对硝基苯酚

为探寻硝基芳香族有机污染物的高效降解技术,采用溶胶凝胶法制备了钛基锡系阳极,且掺杂Sb、La等元素对该电极材料进行了改性,并把该系列电极用于电化学处理模拟对硝基苯酚废水。通过SEM和XRD对电极形貌进行表征,分析了元素掺杂改善电极性能的机理,考察了电解条件对电化学降解对硝基苯酚效果的影响,探究了电场因素对电化学体系降解废水的影响机制。通过紫外吸收光谱分析推断了对硝基苯酚在电化学作用下可能的降解历程。研究结果表明：同时掺杂La和Sb的电极降解对硝基苯酚效果最好;在电解电压12 V、极板间距25 mm、pH值为7、电解质浓度0.5 mol/L的条件下电解120 min,对硝基苯酚的降解率可达92.8%,可见应用掺杂La、Sb的Ti/SnO2电极材料的电化学法降解对硝基苯酚优势相当明显。     

Effects of rare earth elements doping on gas sensing properties of ZnO nanowires

The effects of rare earth elements (Ce, Eu, and Er) doping on the microstructure and gas sensing properties of ZnO nanowires were investigated. The Ce, Eu, Er-doped ZnO nanowires and pristine ZnO nanowires were synthesized via a solvothermal route. The structure of the prepared samples was studied and compared by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron microscopy. The gas sensors were fabricated by coating the prepared samples on aluminum oxides tube-based Au sensing electrode, with Ni-Cr heating wire to control the operating temperature. The operating temperature of all sensors was determined to be 300 °C with consideration of ethanol response. At this temperature, all sensors showed good ethanol sensing performance, with the 1%Ce-doped ZnO nanowires-based sensor exhibited the highest ethanol response over the other sensors. The mechanism for the microstructure and gas sensing behavior difference of various samples was discussed.     

铝合金Ce-Mn转化膜的制备工艺研究

以硝酸铈和高锰酸钾为主盐,以氟化钠为促进剂,在铝合金表面制备Ce-Mn转化膜。通过正交试验确定最佳的钝化工艺条件为:硝酸铈8g/L,高锰酸钾2g/L,氟化钠0.06g/L,pH值2.0,70℃,10min。最佳工艺条件下制备的Ce-Mn转化膜呈金黄色,表面均匀,耐蚀性较好。CeMn转化膜的耐蚀性接近六价铬转化膜的耐蚀性。     

Enhanced high-voltage performance of LiCoO2 cathode by directly coating of the electrode with Li2CO3 via a wet chemical method

Surface modification is an effective method for improving the high-voltage cycling stability of LiCoO₂. In this work, lithium carbonate (Li₂CO₃), the main component of solid electrolyte interphase (SEI) films, is selected as the coating material to modify LiCoO₂ composite electrodes by a wet chemical method, and the effect of the Li₂CO₃ coating time on the electrochemical performance of the LiCoO₂ electrode is investigated. Results show that the Li₂CO₃ coating significantly improves the cycling performances and initial coulombic efficiencies of the LiCoO₂ electrodes in the potential range of 3.0–4.5 V. The electrode with a coating time of 2 min exhibits the best electrochemical performance, in which the capacity retention rate is 90.9% after 100 cycles at 0.2C while the initial coulombic efficiency is 90.04%, whereas the capacity retention rate and initial coulombic efficiency of the uncoated electrode are only 73.11% and 74.66%, respectively. The capacity of the electrode with the 2-min coating reaches 134.3 mA h g^?1 after 500 cycles, while that of the uncoated electrode is only 37.7 mA h g^?1 under the same conditions. The results of cyclic voltammetry, electrochemical impedance spectroscopy, X-ray diffraction, and scanning electron microscopy show that the Li₂CO₃ coating stabilizes the electrode surface and structure to effectively inhibit the increase in electrode polarization.     

Effects of Annealing Temperature on the Structure and Capacitive Performance of Nanoscale Ti/IrO2–ZrO2 Electrodes

Electrodes consisting of coating of the Iridium oxide–Zirconium oxide (70%IrO₂–30%ZrO₂) binary oxide were formed on Ti substrates by thermal decomposition and annealing at 340°C–450°C. The effects of the annealing temperature on the structure, surface morphology, surface composition, and capacitive performance of the coatings were investigated using X‐ray diffraction analysis (XRD), transmission electron microscopy (TEM), scanning electron microscopy, X‐ray photoelectron spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy (EIS). The XRD and TEM analyses showed that 360°C is greater than but very close to the crystallization temperature of the 70%IrO₂–30%ZrO₂ oxide coating. The 70%IrO₂–30%ZrO₂ oxide coatings annealed at this temperature consisted of an amorphous matrix containing a few IrO₂ nanocrystalline particles (diameter of 1–2 nm). The degree of crystallinity of the coatings was approximately 13.2%. EIS analysis showed that the electrode annealed at 360°C exhibited the highest specific capacitance, which was much higher than that of the electrode annealed at 340°C (which had a purely amorphous structure) as well as those of the electrodes annealed at 380°C and 400°C (which had higher degrees of crystallinity). On the basis of the obtained results, the following conclusion can be drawn: oxide coatings prepared at temperatures slightly higher than the crystallization temperature of the oxide and containing conductive nanocrystalline particles exhibit the best capacitive performance. We suggest that this phenomenon can be explained by the fact that the electronic conductivity of the coating is greatly improved by the presence of the homogeneously distributed conductive nanocrystalline particles in the amorphous matrix. Furthermore, the protonic conductivity and loose atomic configuration of the amorphous structure of the electrode are not adversely affected by the annealing treatment.