阳极Pb(II)氧化物膜的阴极还原

采用X射线衍射、光电流谱、线性电位扫描和开路电位衰退等方法研究了Pb电 极在0.9 V(vs.Hg/Hg_2SO_4), 4.5 MOL/l h_2so_4溶液中生长2 h所得的阳极Pb (II)氧化物膜的阴极还原行为。实验结果表明；阳极Pb(II)氧化物膜主要由PbO微 粒和PbO·PbSO_4微粒组成，微粒间液膜可供离子输运；在LSV负向扫描过程中，阳 极Pb(II)氧化物膜是按溶解－沉积机理还原的，首先PbO微粒借助该微粒间的液膜 还原为金属铅，而待PbO微粒表面层转化的金属铅与PbO·PbSO_4微粒接触后，则 PbO·PbSO_4就和PbO一起还原，而以PbO·PbSO_4的还原进程略快。     

铅锡合金在硫酸溶液中生长阳极Pb(Ⅱ)氧化物膜的机理

用交流阻抗、开路电位衰退及线性电位扫描等方法在0.9V(vs.Hg/Hg₂SO₄)和4.5mol/LH₂SO₄溶液中,研究了铅及Pb-Sn合金电极上所生长的阳极氧化物膜.实验结果表明,阳极膜由溶解-沉淀机理控制生长,膜中微粒间为液膜,借助液膜作为离子通道可使膜中微粒发生阳极反应,锡有利于膜中PbO微粒表层阳极氧化为PbO^1+x(0相似文献   

铈降低在硫酸溶液中生长的阳极Pb(II)氧化物膜的电阻的研究

应用电化学阻抗频谱法、线性电位扫描法和光电流技术研究了在4.5 mol· dm~(-3) H_2SO_4溶液中Pb-1%(at.)Ce（简称Pb-1Ce）合金在0.9 V (vs. Hg/Hg_2SO_4电极)生长的阳极Pb(II)氧化物膜的电阻较纯铅的低的原因。实验结 果表明,Ce阻抑阳极Pb(II)氧化物膜的生长并增加其孔率,从而降低其电阻。     

铈降低在硫酸溶液中生长的阳极Pb(II)氧化物膜的电阻的研究

应用电化学阻抗频谱法、线性电位扫描法和光电流技术研究了在4.5 mol· dm~(-3) H_2SO_4溶液中Pb-1%(at.)Ce（简称Pb-1Ce）合金在0.9 V (vs. Hg/Hg_2SO_4电极)生长的阳极Pb(II)氧化物膜的电阻较纯铅的低的原因。实验结 果表明，Ce阻抑阳极Pb(II)氧化物膜的生长并增加其孔率，从而降低其电阻。     

电化学方法分析铅阳极膜的相组成

本文提出使用线性电位扫描和电位衰退定性和定量分析铅在4.5mol·dm^-^3H2SO4(30℃)中形成的阳极膜的相组成并与现场X射线衍射, 原子吸收光谱, 阳极溶出等法比较。结果表明电位扫描伏安曲线的峰电位和电位扫描至峰电位左右时电极开路后, 所得的稳定电位可用于阳极膜相组成的定性分析, 电位扫描伏安电线电流峰的面积可用于阴极膜相组成的定量分析。本文的阳极膜由PbO·PbSO4, PbO2和PbOn(2>n>1)组成, 以PbO·PbSO4为主要成份。     

铅锑合金在硫酸溶液中的阳极膜——Ⅰ.早期阳极膜生长动力学

本文用线性电位扫描法(20 mV·s~(-1)),自1.2 V(vs.Hg/Hg_2SO_4)扫描至-1.2V,研究了三种铅锑合金在4.5 MH_2SO_4溶液中(30℃),经一定时间(60,600,1200,和2400s)1.2 V 阳极极化形成的阳极膜.该阳极膜的主要成分可能是 PbO·PbSO_4,其表面为 PbO_2.本文推导出与实验一致的此种阳极膜的生长动力学方程式,并利用该式测得氧原子在阳极膜中的扩散系数.     

阳极二氧化铅膜的阴极还原为硫酸铅的机理

应用旋转环盘电极, 和静止电极线性电位扫描法(LSV)研究铅上阳极PbO~2膜的阴极还原为PbSO~4的机理。实验结果表明相应于Pb盘上阳极膜中PbO~2还原时所产生的Pb-7w/oSb环电流是原先PbO~2膜生长时析出的氧扩散入膜中以及膜内的PbO~2微粒中的品种逸出而被还原所致。无可溶性中间体可被检出。扫速对静止Pb上阳极膜中PbO~2的LSV法还原的影响符合薄膜反应的规律。本文提出了上述反应机理。     

电解液对全铅单液流电池电极性能的影响

研究Pb(II)和H+离子浓度对全铅单液流电池正、负电极在复合石墨基体上电化学行为的影响.结果表明,PbO2正极和Pb负极的电极过程受电化学和扩散混合控制.Pb(II)氧化沉积成PbO2时出现成核环,铅负极成核过电位小,充放电电压差远小于PbO2正极,电池极化主要来自PbO2正极.增加H+浓度有利于降低PbO2正极和Pb负极的极化,但析氧、析氢副反应和腐蚀加重.增大Pb(II)浓度有利于抑制析氧,但PbO2正极充电电压升高,充放电电压差增大.Pb(II)浓度较低时,充放电过程中PbO2沉积层少许脱落,充电电压进一步降低且更趋平稳.为此,电解液中HBF4浓度以2 mol L-1为宜,Pb(II)浓度应在0.9 mol L-1以上.     

Pb及Pb-7w/O Sb合金在氧析出电位区生长的阳极膜

分别测量了Pb及Pb-7w/0Sb在4.5mol·dm~(-3)H_2SO_4(30℃)中于1.3和1.5V(vs. Hg/Hg_2SO_4/4.5mol·dm~(-3)H_2SO_4)下在不同时间生长的阳极膜的交流阻抗谱,并使用线性电位扫描法分析了上述阳极膜的相组成。讨论了上述阳极膜进行的电化学反应的机理,并据此提出它们的等效电路。实验结果表明上述阳极膜的真实表面积随生长时间而增加,该膜多孔,主要由外层为PbO_2的PbO·PbSO_4微粒组成。锑能显著抑制PbO_2的生长,特别是在1.3V时。     

铅上阳极硫酸铅膜的还原过程

采用线性电位扫描法、电位阶跃法, 结合交流阻抗跟踪对铅在4.5mol.dm^-^3H2SO4中-0.6V(vs. Hg/Hg2SO4/4.5mol.dm^-^3H2SO4)极化20min形成的阳极硫酸铅膜的阴极还原进行研究。实验结果表明该膜大部分能被还原, 其中的硫酸铅颗粒先在表面按扩散控制下的三维瞬时成核与生长机理被还原, 然后Pb^2^+自颗粒内径向扩散至已生成的铅层表面上进行还原。颗粒中微粒间的液膜为离子输运的主要途径。     

Effects of Samarium on the Properties of the Anodic Pb(II) Oxides Film Formed on Pb in Sulfuric Acid Solution

ＩｎｔｒｏｄｕｃｔｉｏｎＡｎｔｉｍｏｎｙ ｆｒｅｅＰｂ Ｃａａｌｌｏｙｓｈａｖｅｃｏｍｍｏｎｌｙｂｅｅｎｕｓｅｄｉｎｔｈｅｍａｎｕｆａｃｔｕｒｅｏｆｇｒｉｄｓｉｎｏｒｄｅｒｔｏｍｉｎｉｍｉｚｅｇａｓｓｉｎｇｉｎｅｉｔｈｅｒｌｏｗ ｍａｉｎｔｅｎａｎｃｅｏｒｖａｌｖｅ ｒｅｇｕｌａｔｅｄｌｅａｄａｃｉｄｂａｔｔｅｒｉｅｓ .Ｈｏｗｅｖｅｒ ,ｔｈｅｓｅａｌｌｏｙｓｃａｎｃａｕｓｅｏｔｈｅｒｐｒｏｂｌｅｍｓｓｕｃｈａｓｐｒｅｍａｔｕｒｅｃａｐａｃｉｔｙｌｏｓｓ ,ｌｏｗｃｈａｒｇｅ ａｃ ｃｅｐｔａｎｃｅａｎｄ…     

Effects of Samarium on the Properties of the Anodic Pb（Ⅱ） Oxides Film Formed on Pb in Sulfuric Acid Solution

The effects of samarium on the properties of the anodic Pb(II) oxides films formed on lead at 0.9 V (vs. Hg/Hg₂SO₄) in 4.5 mol/L H₂SO₄ solution were studied using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and scanning electron micrographs (SEM). The experimental results show that adding Sm to lead metal can inhibit the growth of the Pb(II) oxides film effectively, and reduce the resistance of the PbO oxides film obviously. The addition of Sm increases the porosity of the anodic film, which may cause the increase of the ionic conductance produced by the interstitial liquid among the PbO particles in the film and lead to the decrease of the resistance of the anodic film.     

硫酸溶液中铅阳极膜研究的几个问题（－）

基于铅酸电池的实际应用以及对铅本身电化学行为的兴趣,人们对铅及其合金在硫酸溶液中形成的阳极膜,已做了大量的研究￣［１～４］。其三大进展为：Ｆｌｅｉｓｃｈｍａｎｎ与Ｔｈｉｒｓｋ￣［５］提出成核与生长机理来解释β－ＰｂＯ＿２的形成;Ｐａｖｌｏｖ￣［６］采用光电化学方法研究ＰｂＯ电位区的固相反应;Ｒｕｅｔｓｃｈｉ￣［７］提出阳极膜最外层ＰｂＳＯ＿４为半透膜,保证膜内部的碱性环境。然而总的来说,各个研究者对铅阳极膜缺乏统一的认识。其主要原因是铅阳极膜相组成复杂,至今尚未完全确定。有鉴于此,我们将陆续介绍本小组对于硫酸溶液中铅阳极膜研究的几个问题所持的观点。     

Thermal characterization of tetrabasic lead sulfate used in the lead acid battery technology

The thermal production of 4PbO·PbSO₄ was comprehensively studied and characterized for two syntheses routes, i.e. either heating 3PbO·PbSO₄·H₂O, or a mixture of 4PbO:PbSO₄, in air to about 700 °C. In the 3PbO·PbSO₄·H₂O approach, the formation of an intermediate amorphous phase occurred at around 210 °C with the loss of H₂O from the hydrated structure. Formation of 4PbO·PbSO₄ initiated at around 270 °C with predominantly 4PbO·PbSO₄ and 13% residual PbO·PbSO₄ existing at 700 °C. With the synthesis route of mixing a stoichiometric ratio of 4PbO with PbSO₄, an intermediate phase of PbO·PbSO₄ formed at around 300 °C, before the 4PbO·PbSO₄ phase started to form at around 500 °C. Upon further heating, 4PbO·PbSO₄ was the predominant phase with 8% of PbO·PbSO₄ remaining. Both samples decomposed upon further heating to 850 °C. Powder neutron diffraction studies of the final 4PbO·PbSO₄ products from the two different synthesis routes showed similar crystallographic unit cell lattice parameters with slight differences in the PbO:PbSO₄ contents. This could possibly be linked to differences observed in the microscopic crystallite shapes from the two synthesis routes.     

Study on Lead Dioxide Modified Electrode and Its Application in Detection of Phenols

IntroductionOflate,thereisagreatinterestintheimprovementofleaddioxideasananodematerialforelectrosynthesis,ozonegenerationandwastewatertreatmentowingtoitshighelectri calconductivity ,largeoxygenoverpotentialandchemicalin ertness.1 5PbO2 canbeobtainedasanodicdepositsfromsolu tionsofthelow valenceions,basicstudiesontheseelec trodesaremainlyconfinedtothenucleationgrowthprocessofleaddioxidecrystallites ,ormodifiedbyothercationsinordertoimproveitsproperties.6 However,itselectrocatalyticactivi tydepe…     

Resistance of the anodic PbO film formed in sulfuric acid solution

The resistance of the anodic PbO film fonned on lead at 0.9 V (vs. Hg/Hg2SO4) in 4.5 mol/dm3 H2SO4 was measured using alternating-current impedance method. The resistance of the anodic PbO film was found to be close to that of the interstitial liquid among the PbO particles in the film, suggesting that the interstitial liquid may serve as the major passage for ion transportation during the film growth.     

硫酸体系中金属盐类对甲烷低温转化的催化活性

 研究了硫酸镍、硫酸钴、硫酸钌、硫酸铑、硫酸银、硫酸镧、硫酸铈、硫酸汞、硫酸铅、偏钒酸钠、高铼酸钾、硫酸钾、硝酸钾、溴化钾和氯化钾在发烟硫酸中对甲烷转化的催化作用. 结果表明,硫酸汞催化活性最高,溴化钾、硫酸银、硫酸镧和硫酸铅也有一定的催化作用. 硝酸钾可以部分催化反应中生成的二氧化硫与氧气反应变回硫酸.