【作者】 薛彩霞；

【导师】 梁镇海；

【作者基本信息】 太原理工大学 ， 物理化学， 2007， 硕士

【摘要】 现代电化学工业中许多生产过程需在强酸的环境中进行，由于酸性溶液的强腐蚀性和阳极放氧的强氧化性，使得满足工业条件的阳极材料十分稀少，优良的阳极要求具有导电性高、催化活性好、寿命长、表面积大、价格低和污染小等优点。目前国内外研究较广泛的耐酸不溶性阳极类型多是以钛为导电基，此种阳极的主要缺点是在电解使用过程中，阳极放出的氧使钛钝化而导致电极电阻增大，电极失效。本文提出了一种以钛为基体，SnO₂+Sb₂O₄+GF（石墨纤维）为中间层，PbO_x或MnO_x为活性层的电极，采用热分解和电沉积组合技术制备了Ti／SnO₂+Sb₂O₄+GF／PbO_x和Ti／SnO₂+Sb₂O₄+GF／Mno_x阳极。利用SEM、XRD和XPS等手段对上述电极表面形貌、结构物相、组成价态进行了表征；采用快速寿命实验考察了该电极在1.0 mol／L H₂SO₄溶液中4A／cm²下的预期使用寿命；采用三电极体系测定了上述电极在不同溶液中的循环伏安曲线，同时利用循环伏安曲线求得了电极表面的分形维数、活化能、氢离子反应级数和动力学参数等；并对析氧反应机理进行了探讨。结果表明：（1）Ti／SnO₂+Sb₂O₄+GF/PbO_x和Ti／SnO₂+Sb₂O₄+GF／MnO_x电极在1.0mol／L H₂SO₄溶液中，工业电流密度下（1000A／m²）预期使用寿命分别约为22年和3.65年，上述两种电极寿命均比一般氧化物电极的寿命长，尤其前者更为明显。（2）Ti／SnO₂+Sb₂O₄+GF／PbO_x电极的析氧动力学参数a、b、i₀依次为0.238V、0.737V和4.75×10^-1A／cm²；Ti／SnO₂+Sb₂O₄+GF／MnO_x电极a、b、i₀分别为0.395V、1.261V和7.70×10^-3A／cm²。两者相比，前者的a、b较小，i₀较大。因此，Ti／SnO₂+Sb₂O₄+GF／PbO_x的电催化性能更好。（3）Ti／SnO₂+Sb₂O₄+GF／PbO_x电极和Ti／SnO₂+Sb₂O₄+GF／MnO_x电极在强酸溶液中的平均活化能分别为14.21 kJ／mol和28.01 kJ／mol，较一般的化学反应活化能低。因此该电极的析氧电催化性能较好。（4）Ti／SnO₂+Sb₂O₄+GF／PbO_x电极和Ti／SnO₂+Sb₂O₄+GF／MnO_x电极在强酸性溶液放氧反应中H⁺的反应级数约为零。（5）Ti／PbO_x类电极OER的历程如下：PbO_2-X+H₂O→PbO_2-X（·OH）+H⁺+e^-PbO_2-X（·OH）→PbO_2-X+1+H⁺+e^-PbO_2-X（·OH）→PbO_2-X+H⁺+e^-+1／2O₂PbO_2-X+1→PbO_2-X+1／2O₂其中，第一步为速度控制步骤，动力学表达式为：i=4k_aF exp[（1-α）F△ψ／RT]-4Fk_c′exp[（1-α）F△F△ψ／RT]更多还原

【Abstract】 Fine anode requests high-conductivity, good catalytic activity, long life, big surface area, low price, small pollution and so on. Because of strong corrosiveness and oxidation of oxygen atom in anodic acid solution, the anode materials is very rare, Therefore it is important to choose and prepare non-precious metal anode.Ti/SnO₂＋Sb₂O₄＋GF/PbO_x and Ti/SnO₂＋Sb₂O₄＋GF/MnO_x anodes were prepared by thermal decomposition and electrodeposition combination technology. Electrodes surface appearance, structure phase and composition valent state were characterized by means of SEM、XRD and XPS、the anticipated service life of the oxide anodes were inspected by fast life test in 1.0mol/L H₂SO₄ solution at 4A/cm², cyclic voltammograms、dynamics parameters、apparent activation energy and reaction order of H⁺ were measured by three electrodes system in acid solution, meanwhile the relationship between fractal dimension and the electrocatalytic activity was discussed. Finally, the mechanism of oxygen evolution was put forward. Results were shown:（1） The anticipated service life of Ti/SnO₂＋Sb₂O4＋GF/PbO_x anode and Ti/SnO₂＋Sb₂O₄＋GF/MnO_x anode in 1.0mol/L H₂SO₄ solution at 1000A/m² industrial current density can reach 22y and 3.65y, which are longer than that of other oxide anodes.（2） The kinetic parameters of Ti/SnO₂＋Sb₂O₄＋GF/PbO_x（a、b、i₀） are 0.238V, 0.737V and 4.75×10^-1A/cm² respectively; them of Ti/SnO₂＋Sb₂O₄＋GF/MnO_x anode are 0.395V, 1.261V and 7.70×10^-3A/cm², a and b of the first anode are smaller, but its i₀ is much longer. So the electrocatalytic properties of Ti/SnO₂＋Sb₂O₄＋GF/PbO_x anode is better than that of Ti/SnO₂＋Sb₂O₄＋GF/MnO_x in acidic solution.（3） The average activation energy of Ti/SnO₂＋Sb₂O₄＋GF/PbO_x anode and Ti/SnO₂＋Sb₂O₄＋GF/MnO_x anode are 14.21 kJ/mol and 28.01 kJ/mol respectively, they are smaller than that of general chemical reaction. So the electrocatalytic properties of above two anodes are good.（4） The reaction order of H⁺ of Ti/SnO₂＋Sb₂O₄＋GF/PbO_x anode and Ti/SnO₂＋Sb₂O₄＋GF/MnO_x anode in acdic solution for OER （oxygen evolution reaction） are approximate 0.（5） The mechanism of OER about Ti/PbO_x anode was proposed: PbO_2-x＋H₂O→PbO_2-x（·OH）H⁺＋e^- PbO_2-x（·OH）→PbO_2-x+1＋H⁺＋e^- PbO_2-x（·OH）→PbO_2-x＋H⁺＋e^-＋1/20₂ PbO_2-x+1→PbO_2-x＋1/20₂The first step is the rate control step, the kinetic expression is shown below: i=4k_α^＇Fexp[（1－α）F△φ/RT]－4Fk_c^＇exp[（1－α）F△φ/RT]更多还原