新型钛基PbO2阳极电氧化降解 有机污染物的特性研究

用电沉积法制备了PbO2/SnO2+Sb2O3/Ti、Bi-PbO2/SnO2+Sb2O3/Ti、PbO2（超声）/SnO2+Sb2O3/Ti、Bi-PbO2（超声）/SnO2+Sb2O3/Ti等4种二氧化铅电极,用稳态极化曲线表征了它们的电催化性和选择性,分析了电解苯酚废水的处理效果,用加速寿命实验测定了电极寿命,用电子扫描电镜表征了沉积层晶相和形貌。结果表明：掺Bi可以提高电极的电催化性和电氧化苯酚的选择性,超声电沉积可以增大电极比表面积,提高电极的表观催化活性,显著增长电极加速寿命。     

Ti/SnO2+Sb2O3/PbO2电极在硫酸溶液中Cr3+氧化的电化学性能

对用聚合前驱体溶液通过热分解法制备的Ti/SnO2+Sb2O3/PbO2电极在硫酸溶液中Cr3+电化学氧化的电化学性能进行了研究. 分别测定了以Ti/SnO2+Sb2O3/PbO2和PbO2为阳极，硫酸介质中Cr3+电化学氧化过程的极化曲线、抗腐蚀性以及不同操作电流密度、Cr3+浓度、反应温度、硫酸浓度下的电流效率. 实验结果表明，聚合前驱体溶液通过热分解法制备的Ti/SnO2+Sb2O3/PbO2电极与PbO2电极相比具有更高的电催化活性和抗腐蚀性.     

不同金属氧化物阳极上甲基橙的电化学氧化降解

分别以Ti/SnO2+Sb2O3和Ti/SnO2+Sb2O3/PbO2电极为阳极进行甲基橙的电化学氧化,研究了两种金属氧化物阳极上甲基橙氧化降解过程的反应速率、电流效率及COD的变化.结果表明,两种金属氧化物阳极都能有效氧化降解甲基橙,氧化反应符合一级反应动力学规律,在Ti/SnO2+Sb2O3和Ti/SnO2+Sb2O3/PbO2电极上甲基橙氧化降解过程的表观速率常数分别为0.148和2.43×10-2 min-1. 以Ti/SnO2+Sb2O3为阳极电解30 min,甲基橙的浓度从初始时的0.305 mmol/L降至4.89×10-3 mmol/L,甲基橙的转化率达98.4%;在Ti/SnO2+Sb2O3/PbO2电极上,相同电解时间下甲基橙的浓度只降至0.14 mmol/L,转化率为55.0%. 对不同电极上甲基橙电化学氧化过程电流效率的研究表明,Ti/SnO2+Sb2O3电极的电流效率明显高于Ti/SnO2+Sb2O3/PbO2电极. Ti/SnO2+Sb2O3电极的反应速率大、电流效率高主要源于其较高的析氧电位.     

不同金属氧化物膜电极上苯酚的电催化氧化

分别以自制的金属氧化物膜电极Ti/SnO2+Sb2O3、Ti/SnO2+Sb2O3/PbO2和Ti/SnO2+Sb2O3/RuO2+PbO2为阳极，恒电流电解低浓度苯酚溶液，研究了不同金属氧化物阳极对苯酚电催化氧化过程的影响。实验结果表明：在实验条件下，苯酚溶液在3种金属氧化物膜电极上的电催化氧化过程的宏观动力学符合一级反应动力学规律，但不同金属氧化物阳极上苯酚电催化氧化过程的表观反应速率及电流效率有明显的差异。25℃下苯酚在Ti/SnO2+Sb2O3、Ti/SnO2+Sb2O3/PbO2和Ti/SnO2+Sb2O3/RuO2+PbO2电极上电催化氧化的表观反应速率常数k分别为6.66×10-2min-1、2.49×10-2min-1和9.76×10-3min-1;瞬时电流效率随电解时间的增长而下降，初始电流效率分别为78.7%、38.9%、13.2%。以Ti/SnO2+Sb2O3电极为阳极电解60 min后，苯酚浓度从初始浓度2.13×10-3mol·L-1降至3.27×10-5mol·L-1，苯酚的转化率达98.5%;而在相同的反应条件下，以Ti/SnO2+Sb2O3/PbO2和Ti/SnO2+Sb2O3/RuO2+PbO2为阳极时，苯酚的转化率只有82.7%和29.8%。对3种电极在苯酚溶液中的伏安特性的研究表明，Ti/SnO2+Sb2O3电极具有比Ti/SnO2+Sb2O3/PbO2和Ti/SnO2+Sb2O3/RuO2+PbO2高的析氧电位，因此有利于有机物的氧化和过程电流效率的提高。     

4种DSA阳极的制备及其电催化性能比较

制备了Ti/SnO2+Sb2O3, Ti/PbO2, Ti/Fe-PbO2和Ti/SnO2+Sb2O3/Fe-PbO2四种形稳阳极材料,对其表面形貌进行了表征,同时测试了其在H2SO4溶液中的极化曲线. 以苯酚为目标污染物,用其进行了电催化降解实验. 结果表明,Ti/SnO2+Sb2O3/Fe-PbO2电极催化活性最好,苯酚降解率可达95%. 添加锡锑中间层后,Ti/SnO2+Sb2O3/Fe-PbO2电极寿命显著提高,可达16 h. 苯酚在4种阳极上的电催化降解反应遵循一级反应动力学规律.     

电解条件对Cr3+电化学氧化过程瞬时电流效率的影响研究

在隔膜式电解槽中,分别以PbO2和Ti/SnO2+Sb2O3/PbO2为阳极,以Cu为阴极,对硫酸介质中影响Cr3+电化学氧化生成Cr2O72-过程瞬时电流效率的因素进行了研究.实验结果表明,在硫酸介质中进行Cr3+电化学氧化时,操作电流密度、反应温度、硫酸浓度、阳极材料、超声等因素都会影响Cr3+电化学氧化生成Cr2O72-过程的瞬时电流效率.瞬时电流效率随操作电流密度和硫酸浓度的增大而下降,随反应温度的升高而增大;Ti/SnO2+Sb2O3/PbO2电极与PbO2电极比有较大的比表面积,瞬时电流效率高于PbO2电极;电解体系中引入超声,减小了电极表面的扩散层厚度,强化了Cr3+向电极表面的传质, 超声场作用提高了瞬时电流效率. 在25℃、硫酸浓度为1.5mol·L-1、 Cr3+浓度为0.070 mol·L-1、操作电流密度为0.02～0.15A·cm-2时,Ti/SnO2+Sb2O3/PbO2为阳极的瞬时电流效率比PbO2电极提高了4%～12%;在Cr3+浓度为0.040mol·L-1下操作,以Ti/SnO2+Sb2O3/PbO2为阳极,有超声场作用的瞬时电流效率比无超声作用时的瞬时电流效率提高了4%～11%.     

钛基掺锑二氧化锡电极中间层对其电氧化性能的影响

采用电沉积–热氧化法制备含有中间层的钛基锑掺杂二氧化锡电极。研究了在含Sn和Sb(摩尔比9∶1)的乙醇溶液中电沉积制备的中间层对Ti/SnO2–Sb电极表面形貌、组成、电氧化性能和寿命的影响。有中间层和无中间层的Ti/SnO2–Sb电极表面均有龟裂。与无中间层的Ti/SnO2–Sb电极相比,有中间层的Ti/SnO2–Sb电极表面Ti含量较少,Sb、Sn含量较高。有中间层的Ti/SnO2–Sb电极的析氧电位较高,寿命较长,对甲基橙的降解率为94.1%(仅比无中间层的Ti/SnO2–Sb电极低1.3个百分点。     

含锡锑中间层的析氧阳极的制备及性能研究

从延缓涂层钛阳极基体钝化的角度出发,采用热分解法制备了含SnO2-Sb2O5中间层的钛基铱钽电极.利用扫描电镜、X射线衍射、能谱等方法对Ti/SnO2-Sb2O5/IrO2-Ta2O5阳极表面的形貌,相结构、元素组成和电化学性能进行了分析.结果表明,Ti/SnO2-Sb2O5/IrO2-Ta2O5阳极的使用寿命较Ti/IrO2-Ta2O5阳极有大幅度的提高,并且具有更高的电催化活性.Ti/SnO2-Sb2O5/IrO2-Ta2O5是一种在酸性环境中非常具有前景的析氧阳极.     

Ti/SnO_2+Sb_2O_4+CF/PbO_2电极在酸性溶液中反应历程的拟定及推导

拟定并推导了Ti/SnO2+Sb2O4+CF/PbO2电极在酸性溶液中的反应历程,确定了速度控制步骤和动力学表达式。     

SnO_2掺杂IrO_2–Ta_2O_5涂层阳极的电催化活性及稳定性

采用热分解法制备了不同SnO2含量(Sn摩尔分数为7.7%、14.3%和20.0%)的Ti基IrO2–Ta2O5–SnO2涂层阳极(Ir与Ta的摩尔比为2∶1),通过循环伏安法、极化曲线测试和交流阻抗谱分析了涂层的电催化活性,采用强化寿命试验测试了阳极的耐腐蚀性能。结果表明,掺杂SnO2后,Ti基IrO2–Ta2O5涂层阳极的催化活性表面积增大,但是析氧电位及涂层的总电阻也增大,耐腐蚀性能降低。SnO2含量为7.7%时综合电催化性能最佳。     

Service life of Ti/SnO2–Sb2O5 anodes

The service life of SnO2–Sb2O5 coated anodes prepared by the spray pyrolysis technique using Ti or Ti/IrO2 substrate, was studied under galvanostatic conditions (100mAcm–2 in 1m H2SO4 at 25°C. The results showed that the presence of an IrO2 interlayer between the Ti substrate and the SnO2–Sb2O5 coating (Ti/IrO2/SnO2–Sb2O5 anode) strongly increases the service life of the anode. This beneficial action of the IrO2 interlayer was attributed to its high anodic stability and its isomorphous structure with TiO2 and SnO2. Cyclic voltammetry and steady-state polarization curves showed that the electrochemical behaviour of the Ti/IrO2/SnO2–Sb2O5 electrode lies between the behaviour of the Ti/IrO2 and the Ti/SnO2–Sb2O5 electrodes due to incorporation of IrO2 in the SnO2–Sb2O5 coating during its preparation.     

Effects of Precursors for Preparing Intermediate Layer on the Performance of Ti/SnO2+Sb2O3/PbO2 Anode

The Ti/SnO2+Sb2O3/PbO2 anode with SnO2+Sb2O3 intermediate layer obtained by the polymeric precursor method (PPM) and with the conventional route was studied. The morphology and microstructure of SnO2+Sb2O3 intermediate layer derived from different precursors and the top PbO2 active layer were examined by means of ESEM and XRD. The lifetime and electrocatalytic activity of the anode were also assessed by the cyclic voltammetry and accelerated lifetime test in 1.0 mol/L H2SO4 solution. It was found that precursor solvents affected lifetime, microstructure and morphology of the anode, and had little influence on electrocatalysis activity of the electrodes. The accelerated lifetime of Ti/SnO2+Sb2O3/PbO2 anode with intermediate layer prepared by PPM was 29.5 h in 1.0 mol/L H2SO4 solution, which was respectively about four times and twice that of the anode prepared with ethylene glycol and ethanol. After the anode was subjected to thermal corrosion, the lifetime still reached 27 h in contrast to the others.     

Ti/SnO_2+Sb_2O_3+MnO_2/PbO_2阳极的制备及其性能

用热分解和电沉积联合方法制备了Ｔｉ／ＳｎＯ２＋Ｓｂ２Ｏ３＋ＭｎＯ２／ＰｂＯ２阳极．对该类电极进行了ＥＤＳ、ＳＥＭ、ＸＲＤ研究．测定了电极在１ｍｏｌ／ＬＨ２ＳＯ４溶液中的使用寿命和动力学参数．考察了其作为阳极用于含酚废水处理时的性能．结果表明，所制备电极在硫酸溶液中具有优良的电催化活性和电化学稳定性．     

Characterization and stability of doped SnO2 anodes

Doped tin dioxide electrodes have been prepared by a standard spray pyrolysis technique. The electrochemical behaviour of these electrodes has been investigated by cyclic voltammetry in sulphuric acid using the Fe2+/Fe3+ redox couple system as test reaction. Oxygen evolution has been used to study the stability of doped SnO2 electrodes. The SnO2 electrodes doped with antimony and platinum exhibit the highest stability. XPS analysis shows that the oxidation state of Sn, Sb and Pt are +4, +3 and +2, respectively, the probable species being SnO2, Sb2O3 and PtO.     

Surface activation of manganese oxide electrode for oxygen evolution from seawater

Utilizing the fact that the equilibrium potential of oxygen evolution is lower than that of chlorine evolution, oxygen evolution in seawater electrolysis was enhanced by decreasing the polarization potential under galvanostatic conditions through increasing the effective surface area of manganese oxide electrodes. Electrodes were prepared by a thermal decomposition method. IrO2-coated titanium (IrO2/Ti electrode) was used as the substrate on which manganese oxide was coated (MnOX/IrO2/Ti electrode). Subsequently, oxide mixtures of manganese and zinc were coated (MnOX–ZnO/MnOX/IrO2/Ti electrode). The effective surface area of the MnOX–ZnO/MnOX/IrO2/Ti electrodes was increased by selective dissolution of zinc (leaching) into hot 6M KOH. The oxygen evolution efficiency of the MnOX/IrO2/Ti electrode was 68–70%. Leaching of zinc from the MnOX–ZnO/MnOX/IrO2/Ti electrodes with 25mol% or less zinc led to a significant increase in the oxygen evolution efficiency. The maximum efficiency attained was 86% after leaching of zinc from the MnOX–25mol%ZnO/MnOX/IrO2/Ti electrode. However, large amounts of zinc addition, such as 40mol% or more are detrimental because of a decrease in the oxygen evolution efficiency. This is due to the formation of a double oxide, ZnMnO3, which is hardly dissolved in hot 6M KOH.     

钛基锡锑氧化物电极在合成偶氮二甲酰胺中的应用

采用热分解法制备的SnO2+Sb2O3/Ti作为阳极材料,以联二脲为原料,电化学氧化法合成出偶氮二甲酰胺。通过单因素实验和正交实验研究了电流密度、电量、NaBr的质量浓度和H2SO4的浓度以及反应温度对偶氮二甲酰胺的产率和电流效率的影响。得出最佳工艺条件:电流密度2 300 A/m2,电量12 350 C,NaBr的质量浓度和H2SO4的浓度分别为8 g/L和1.47 mol/L,温度40℃。在最佳条件下,偶氮二甲酰胺的产率达94%,质量分数97%,电流效率89%。此外,SnO2+Sb2O3/Ti电极在NaBr和H2SO4的溶液中的循环伏安测试结果表明,吸附溴原子Brad复合成溴的步骤控制电合成偶氮二甲酰胺的反应速度。整个电极过程包括电子转移及后续的化学反应(EC机理)。