不同浓度盐酸刻蚀对钛基锡锑钌氧化物涂层电极活性和寿命的影响
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摘要
钛基体的酸刻蚀是钛基氧化物涂层电极能否在湿法冶金中应用的关键前处理步骤。采用不同质量分数(5%,10%,15%,20%,25%)的盐酸溶液刻蚀钛基体并制备钛基锡锑钌氧化物涂层电极。通过扫描电镜、电化学工作站及加速腐蚀测试对电极的表面形貌、电催化活性及强化寿命进行了表征,以获得钛基体刻蚀的最佳盐酸浓度。结果表明:随着盐酸浓度升高,钛基体表面腐蚀的程度加深,孔径变大,从纳米级至数微米,扩孔腐蚀起主导作用;随着盐酸浓度的升高,刻蚀后制备的涂层电极的析氧过电位和电荷传递电阻先减小后增大,伏安电量先增大后降低;当盐酸浓度为20%时,刻蚀后制备的涂层电极的析氧过电位最低,其值为274.6 m V(500 A/m~2),电荷传递电阻最低,为0.216 5Ω·cm~2,伏安电量最高,达0.029 9 C/cm~2;在150 g/L H2SO4溶液中以1 A/cm~2的电流密度条件进行加速寿命试验结果显示,浓度为20%的盐酸刻蚀后制备的电极具有最长的使用寿命,其电极寿命为80 h,是浓度为5%的盐酸刻蚀后制备的电极寿命的2.85倍。
Acid etching of titanium matrix is the most critical pretreatment step for titanium-based oxide coated electrodes in hydrometallurgy. In this paper,hydrochloric acid solutions with different concentrations( 5%,10%,15%,20%,25%) were used for etching titanium substrate to prepare titanium based Sn-Sb-Ru oxide coating electrodes. The surface morphology,electrocatalytic activity and service life of the electrode were characterized by scanning electron microscopy,electrochemical workstation and accelerated corrosion testing. Results showed that with the increase of hydrochloric acid concentration,the surface corrosion of titanium substrate was worsened,and the pore size became larger and changed from nanometer to several micrometers,and the reaming corrosion played a dominant role. Besides,the oxygen evolution overpotential and charge transfer resistance of the electrode firstly decreased and then increased,whereas the voltammetric charge firstly increased and then decreased. When the hydrochloric acid solution was 20%,the oxygen evolution overpotential was the lowest with the value of 274.6 m V( at 500 A/m~2),and the charge transfer resistance reached the lowest value of 0.216 5 Ω·cm~2,as well as the voltammetric charge reached the maximum of 0.029 9 C/cm~2. Furthermore,the accelerated life test was carried out in 150 g/L H2 SO4 solution at the current density of 1 A/cm~2,which showed that the electrode prepared after 20% hydrochloric acid treatment had the longest service life and reached 80 h,2.85 times longer than that of the electrode life after hydrochloric acid treatment at a concentration of 5%.
Acid etching of titanium matrix is the most critical pretreatment step for titanium-based oxide coated electrodes in hydrometallurgy. In this paper,hydrochloric acid solutions with different concentrations( 5%,10%,15%,20%,25%) were used for etching titanium substrate to prepare titanium based Sn-Sb-Ru oxide coating electrodes. The surface morphology,electrocatalytic activity and service life of the electrode were characterized by scanning electron microscopy,electrochemical workstation and accelerated corrosion testing. Results showed that with the increase of hydrochloric acid concentration,the surface corrosion of titanium substrate was worsened,and the pore size became larger and changed from nanometer to several micrometers,and the reaming corrosion played a dominant role. Besides,the oxygen evolution overpotential and charge transfer resistance of the electrode firstly decreased and then increased,whereas the voltammetric charge firstly increased and then decreased. When the hydrochloric acid solution was 20%,the oxygen evolution overpotential was the lowest with the value of 274.6 m V( at 500 A/m~2),and the charge transfer resistance reached the lowest value of 0.216 5 Ω·cm~2,as well as the voltammetric charge reached the maximum of 0.029 9 C/cm~2. Furthermore,the accelerated life test was carried out in 150 g/L H2 SO4 solution at the current density of 1 A/cm~2,which showed that the electrode prepared after 20% hydrochloric acid treatment had the longest service life and reached 80 h,2.85 times longer than that of the electrode life after hydrochloric acid treatment at a concentration of 5%.
引文
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[21] MONTILLA F,Morallón E,DE BATTISTI A,et al. Preparation and Characterization of Antimony-Doped Tin Dioxide Electrodes. Part 1. Electrochemical Characterization[J].Journal of Physical Chemistry B,2004,108(16):213-217.
[2]杨德钧,沈卓身.金属腐蚀学[M].北京:冶金工业出版社,1999:339-340.
[3]但建明,陈康宁.影响电极表面形态及电性能因素的分析[J].氯碱工业,2000(11):11-15.
[4] NAM K W,LEE E S,KIM J H,et al. Effect of Etching Ti Substrate on a Catalytic Oxide Electrode[J]. Journal of the Electrochemical Society,2005,2001,148(3):B111-B115.
[5]徐浩,延卫,游莉.不同酸处理对钛基体性能的影响[J].稀有金属材料与工程,2011,40(9):1 550-1 554.
[6]敦敏,彭乔,隋永强,等.钛在海水中的阴极极化行为[J].材料保护,2016,35(3):23-24.
[7] ZHENG Y,SU W,CHEN S,et al. Ti/Sn O2-Sb2O5-Ru O2/α-Pb O2/β-Pb O2electrodes for pollutants degradation[J].Chemical Engineering Journal,2011,174(1):304-309.
[8] YANG H T,CHEN B,LIU H,et al. Effects of manganese nitrate concentration on the performance of an aluminum substrateβ-Pb O2-Mn O2-WC-Zr O2,composite electrode material[J]. International Journal of Hydrogen Energy,2014,39(7):3 087-3 099.
[9] LAI Y,LI Y,JIANG L,et al. Electrochemical behaviors of co-deposited Pb/Pb-Mn O2,composite anode in sulfuric acid solution-Tafel and EIS investigations[J]. Journal of Electroanalytical Chemistry,2012,671(5):16-23.
[10] XU R D,HUANG L P,ZHOU J F,et al. Effects of tungsten carbide on electrochemical properties and microstructural features of Al/Pb-PANI-WC composite inert anodes used in zinc electrowinning[J]. Transactions of Nonferrous Metals Society of China,2012,22(7):1 693-1 700.
[11] YANG H T,LIU H R,GUO Z C,et al. Electrochemical behavior of rolled Pb-0.8%Ag anodes[J]. Hydrometallurgy,2013,140:144-150.
[12] IVANOV I,STEFANOV Y,NONCHEVA Z,et al. Insoluble anodes used in hydrometallurgy:Part II. Anodic behaviour of lead and lead-alloy anodes[J]. Hydrometallurgy,2000,57(2):125-139
[13] Kry'sa J,KULE L,Mráz R,et al. Effect of coating thickness and surface treatment of titanium on the properties of Ir O2-Ta2O5anodes[J]. Journal of Applied Electrochemistry,1996,26(10):999-1 005.
[14] KRYSA J,MRAZ R. Experimental investigation of the double layer capacity,X-ray diffraction and the relative surface content of Ti H2,during pretreatment of titanium used for the preparation of dimensionally stable anodes with Ru O2and/or Ir O2coating[J]. Electrochimica Acta,1995,40(12):1 997-2 003.
[15]田英姿,陈克复.用压汞法和氮吸附法测定孔径分布及比表面积[J].中国造纸,2004,23(4):21-23.
[16]曾人杰.无机材料化学(上)[M].厦门:厦门大学出版社,2001:187-213.
[17]梁镇海.固溶体中间层钛基氧化物阳极研究[D].太原:太原理工大学,2006:71-74.
[18] Hummelgrd C,KARLSSON R K B,Bckstr9m J,et al.Physical and electrochemical properties of cobalt doped Ti-Ru O2electrode coatings[J]. Materials Science&Engineering B,2013,178(20):1 515-1 522.
[19] Spasojevic'M,Ribic'-Zelenovic'L,Spasojevic'P. Microstructure of new composite electrocatalyst and its anodic behavior for chlorine and oxygen evolution[J]. Ceramics International,2012,38(7):5 827-5 833.
[20] SILVA L M D,FARIA L A D,BOODTS J F C. Electrochemical impedance spectroscopic(EIS)investigation of the deactivation mechanism,surface and electrocatalytic properties of Ti/Ru O2(x)+Co3O4(1-x)electrodes[J]. Journal of Electroanalytical Chemistry,2002,532(1):141-150.
[21] MONTILLA F,Morallón E,DE BATTISTI A,et al. Preparation and Characterization of Antimony-Doped Tin Dioxide Electrodes. Part 1. Electrochemical Characterization[J].Journal of Physical Chemistry B,2004,108(16):213-217.