Study On Ti/MO₂ Anode With Intermediate Layers Of Graphite Fiber

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]...