【作者】 孙颜发；

【导师】 梁镇海；

【作者基本信息】 太原理工大学 ， 应用化学， 2009， 硕士

【摘要】 掺杂二氧化锡涂层钛阳极是一类活性高、成本低的耐酸阳极,在电化学合成、废水处理等方面具有较好发展前景。但目前该类阳极在强酸性溶液中使用存在的明显问题是:①阳极放出的活性氧与钛基体形成二氧化钛绝缘层使导电能力降低;②钛基体与活性层结合力差,活性层易脱落,导致阳极失活。通过添加晶体结构相似,能形成有限或连续固溶体结构的组分来增强阳极的稳定性。其中锑、锰掺杂二氧化锡固溶体(Sn1-XSbXO2和Sn1-XMnXO2)是增强阳极导电性与稳定性的有效组分。但目前对该类固溶体形成作用机制的理论研究还甚少,阻碍了钛阳极的进一步发展。本文系统研究了Sn1-XSbXO2和Sn1-XMnXO2固溶体及其相图。①采用化学共沉淀法制备了一系列Sn1-XSbXO2和Sn1-XMnXO2固溶体,采用热分解法制备了Ti/SnO2+MnOx+Y/PbO2阳极;②利用XRD、TG-DTA和XPS技术对固溶体在600℃~1000℃退火温度下的物相组成进行了分析;③根据XRD和TG-DTA的分析结果绘制了固相线下Sn1-XSbXO2和Sn1-XMnXO2固溶体相图;④利用交流阻抗技术分析了Ti/SnO2+MnOx+Y/PbO2阳极的导电性和稳定性。结果表明:1.采用化学共沉淀法制备的Sn1-XSbXO2和Sn1-XMnXO2固溶体颗粒均是纳米级的,颗粒细小且均匀。2.在600℃~1000℃退火温度下,Sn0.95Sb0.05O2只存在单一的四方金红石型SnO2物相,锑主要以Sb2O5的形式进入SnO2晶格内形成有限固溶体,固溶的方程式为: ;Sn0.95Mn0.05O2和Sn0.9Mn0.1O2固溶体也只检测到四方金红石型SnO2物相,锰主要以Mn2O3的形式进入SnO2晶格内形成有限固溶体,固溶的方程式为:。3.固相线下Sn1-XSbXO2(x = 0~1)固溶体相图大致分为三个区域:四方SnO2单相区、SnO2+Sb2O4两相区和斜方Sb2O4单相区,四方SnO2单相区是(Sn, Sb)O2ss固溶体(锑主要以Sb2O5的形式进入SnO2晶格内,并达到饱和);Sn1-XMnXO2(x = 0~1)固溶体相图也大致分为三个区域:四方SnO2单相区,SnO2+Mn2O3和SnO2+Mn3O4两相区,立方方铁锰矿型Mn2O3单相区(或四方黑锰矿型Mn3O4单相区),四方SnO2单相区是(Sn, Mn)O2ss固溶体(锰主要以Mn2O3的形式进入SnO2晶格内,并达到饱和)。(Sn, Sb)O2ss和(Sn, Mn)O2ss固溶体均可作为导电性好和耐腐蚀的耐酸阳极材料。4.热分解法制备的Ti/SnO2+MnOx+Y/PbO2阳极在2 A·cm-2的电流密度下,0.5 mol·L-1 H2SO4溶液中的预期使用寿命可达70 h。更多还原

【Abstract】 Titanium anodes have good prospects for development in electrochemical synthesis and wastewater treatment. They are a type of high activity and low-cost acid-proof anodes. However, the disadvantage is that the evolving oxygen diffusing into the substrate to form an insulator (TiO2) can cause a reduction of conductivity and weaken the binding of activated layer to the substrate, the former will detach from the titanium support, especially in a strong acid electrolyte. Addition of oxides as an intermediate layer, such as Sn1-XSbXO2 or Sn1-XMnXO2, all form of a solid solution, can enhance the conductivity and stability. However, the formation and effects mechanism of solid solution on the performance of anode has been rarely studied, so the theory has lagged behind and hindered titanium anodes further development.The solid solutions (Sn1-XSbXO2 and Sn1-XMnXO2) and their phase diagrams were systematically studied in this paper. Firstly, a series of solid solutions were prepared using chemical coprecipitation method and Ti/SnO2+MnOx+Y/PbO2 anodes were prepared using thermal decomposition method. Secondly, phase composition of the solid solutions at 600℃~1000℃annealing temperatures were analysed using XRD, TG-DTA, and XPS. Thirdly, subsolidus phase diagram of the solid solutions were drawed according to analysis results. Finally, the conductivity and stability of Ti/SnO2+MnOx+Y/PbO2 anodes were analysed using AC impedance method. The conclusions are as follows:1. The nano-particles of Sn1-XSbXO2 and Sn1-XMnXO2 are small and uniform.2. Only quartet rutile SnO2 exists in Sn0.95Sb0.05O2 at 600℃~1000℃annealing temperatures. Antimony is mainly in the form of Sb2O5 incoporated into SnO2 lattice to form a limited solid solution. The equation is . Only quartet rutile SnO2 exists in Sn0.95Mn0.05O2 and Sn0.9Mn0.1O2. Manganese is mainly in the form of Mn2O3 incoporated into SnO2 lattice to form a limited solid solution. The equation is .3. Subsolidus phase diagram of Sn1-XSbXO2 is divided into three regions: quartet SnO2 single-phase region, SnO2+Sb2O4 two-phase region, oblique Sb2O4 single-phase region. Quartet SnO2 single-phase region is (Sn, Sb)O2ss (Antimony is mainly in the form of Sb2O5 incoporated into SnO2 lattice). Subsolidus phase diagram of Sn1-XMnXO2 is divided into three regions: quartet SnO2 single-phase region, SnO2+Mn2O3 and SnO2+Mn3O4 two-phase regions, cubic Mn2O3 bixbyite single-phase region (quartet Mn3O4 hausmannite single-phase region). Quartet SnO2 single-phase region is (Sn, Mn)O2ss (Manganese is mainly in the form of Mn2O3 incoporated into SnO2 lattice). (Sn, Sb)O2ss and (Sn, Mn)O2ss can be used as good electrical conductivity and corrosion resistance of acid-proof anode materials.4. The expected service life of Ti/SnO2+MnOx+Y/PbO2 anode can reach 70 h in 0.5 mol·L-1 H2SO4 solution under the condition of 2 A·cm-2 current density.更多还原