棒状钛包铝基改性二氧化铅复合电极材料的制备及其电化学性能研究

The titanium-based dimensionally stable anode(DSA) is widely used in electrometallurgy, electroplating and cathodic protection and other fields. On the basis of previous research work, aiming at defects of traditional anode used in zinc electrowinning, we propose a novel material clavate titanium clad aluminum substrate lead dioxide composite electrode material modified by doping CeO2, WC, ZrO2 and PAN functional solid particles, which prepared by extrution-drawing and pulse electrodeposition methods. Through controlling process parameters and plating bath component, the technical system of preparation novel material will be established and the modulation of its structure and function will be realized. We plan to study the principle and electrochemical properties of electrode in increasing electrocatalytic activity, decreasing cell voltage and improving quality of cathode zinc; explain connections between microstructure transformation of active coating and its physical electrochemical properties; resolve such critical scientific problems: incorporation of the two solid phase titanium and aluminum, the co-deposition uniformity of solid particles in and conductive ceramic layer lead dioxide, the bonding force of coating and substrate and reduction of cell voltage; investigate the mechanism of mutual embedding of titanium and aluminum and anodizing composite electrodeposition. In the project, a novel substrate base material is proposed, the component design of electrode active layer and preparation technology are practical. The project based on earlier studies is unique and original based on earlier studies. It has certain academic value and scientific significance to study the mechanism of imperfect composite electrodeposition theory that is incompleted yet.

针对工业电解锌中传统阳极材料的缺陷，采用挤压拉拔复合法和脉冲阳极氧化法电沉积制备掺杂CeO2 WC、ZrO2、PAN等功能性固体颗粒的棒状钛包铝基改性β-PbO2复合电极材料。通过适宜的工艺使钛铝紧密复合成型，调整脉冲参数、镀液组成、工艺条件确定最佳制备技术体系。探究电极在提高电催化活性、降低槽电压和改善阴极产品质量方面的本质原因和电化学特性；研究活性层微观组织结构变化与其内应力、结合力、析氧过电位、电催化活性、耐腐蚀性等物理及电化学性能的关系及规律。解决钛、铝相互嵌入、导电陶瓷层PbO2与固体颗粒共沉积的均匀性及其与基体间的结合力、降低析氧过电位等关键科学问题。探究钛-铝相互嵌入机制、阳极氧化复合电沉积机理。项目在基体材料的选择与设计新颖，电极活性层成分的设计与制备技术实用，有扎实的前期工作基础，独具特色与创新；机理研究对丰富尚不完善的复合电沉积理论有一定学术价值和科学意义。

电积锌工业中,阳极在节能降耗、稳定镀液等方面至关重要.开发新型惰性阳极有重要的理论价值和现实意义.项目采用脉冲阳极氧化法制备功能颗粒改性的系列棒状Ti/Al/Ti/β-PbO2复合电极材料；揭示电极结构与性能的构效关系,探究其腐蚀行为及PbO2沉积机理,探讨有机添加剂及固体颗粒对β-PbO2沉积过程的影响规律.获得以下结论:经700℃热处理的钛铝界面呈TiAl3冶金结合层,PbO2与基体间存在张应力,拉曼光谱测量应力的计算式：应力 = 1052.594 MPa/cm-1 ×（519.066 cm-1－拉曼主峰位置）.确定了系列复合电极优化制备工艺；改性Ti/Al/Ti/β-PbO2具有良好的耐蚀性和催化活性；掺杂微纳米颗粒可有效使PbO2晶粒细化,镀层致密,缺陷少、比表面积大；WC和MWCNTs可明显提高电极催化活性、降低反应活化能.Ti/Al/Ti/β-PbO2阳极因铝的内嵌,比Ti/β-PbO2具有更好的耐蚀性.其腐蚀机理为：PbO2与H+生成Pb4+,再与水生成Pb(OH)4,聚合为n [Pb(OH)4],生成[Pb(OH)2]n,生成PbSO4.电解锌液中Mn2+5g·L-1时,阳极表面生成少量MnO2,填补PbO2层的裂缝,有效增强耐腐蚀性和电催化活性.功能颗粒的加入,使活性层晶粒细化、电催化活性增强,降低了析氧电位和槽电压,实现节能降耗.PbO2电沉积是受扩散控制的不可逆过程,机理为：H2O分解为·OH,吸附在电极界面,·OHads与Pb2+生成Pb(OH)2+,再氧化为Pb(OH)3+,最后脱H+生成PbO2.旋转圆盘电极研究表明,转速增加,扩散阻力减小,Pb2+沉积速率加快,使镀层疏松,耐蚀性减小.AEO存在时, PbO2电结晶符合Scharifker-Hills连续成核模式.PEG加入使PbO2电结晶由Scharifker-Hills连续成核模式向瞬时成核模式转变.Tween-80的加入阻碍Pb2+的传质过程,阳极极化增大,形核过程增强,晶粒细化.ZrO2可增加电极比表面积和反应活性点数目.纳米MWCNTs可吸附Pb2+,抑制Pb2+向阳极扩散,浓差极化增大,促进PbO2晶核形成,抑制晶核生长.项目的研究成果,可为湿法冶金用阳极的开发和应用提供新思路,为复合电沉积及机理研究提供参考；若能实现工业化,有望改善能耗与寿命等问题,满足节能降耗要求.