【作者】 秦亮；

【导师】 王玲； 陶杰；

【作者基本信息】 南京航空航天大学 ， 材料学， 2007， 硕士

【摘要】 TiO₂/Ti是一种高耐腐蚀性的电极材料,纳米Pt是一种具有高催化活性的催化剂,而Pt粒子的形状、大小以及分布往往决定催化活性的高低。因此,为了制备一种高催化活性的复合电极,本项工作开拓性地采用阳极氧化-阴极电沉积两步法并在电沉积过程中加入超声作用制备出一种特殊的Pt-TiO₂/Ti纳米复合结构电极,并对其电化学性能进行了研究。以氢氟酸为电解液,采用恒压阳极氧化方法在纯钛箔上获得TiO₂纳米管;随后以氯铂酸为电解液,采用恒流电沉积方法在TiO₂纳米管上沉积Pt。分别采用场发射扫描电镜（FESEM）和X射线衍射仪（XRD）系统地研究了阳极氧化工艺参数（如电压、阳极氧化时间）对TiO₂纳米管形貌和晶型的影响,以及电沉积工艺参数（如电解液浓度、电流密度、沉积时间）对纳米Pt沉积形貌和晶型的影响。结果表明,在电压为20V阳极氧化时间为25min时可以在钛箔上获得结构规整的TiO₂纳米管结构;当电解液浓度低或电流密度小沉积得到的多为颗粒状Pt,而当电流密度增大,或沉积时间延长可以得到花状或草丛中的层片Pt结构。另外,当电解液浓度为1.0g/L电流密度为5mA/cm2时引入超声作用,沉积1min可以得到上部为Pt纳米管下部为TiO₂纳米管的特殊复合结构。此外,还研究了Pt-TiO₂/Ti纳米复合电极在浓度为0.5mol/L的硫酸中的极化曲线和循环伏安曲线,以及该复合电极对甲醇的电催化氧化效果。结果显示,该复合电极的电化学性能和电催化氧化性能均比一般的铂电极和Pt/Ti电极好。在浓度为1.0g/L电解液中,电流密度为5mA/cm2,超声沉积10min制备的复合电极对甲醇氧化的电催化性能最好。更多还原

【Abstract】 TiO₂/Ti is an electrode with high corrosion resistance. And nano Pt is a catalyst with high catalytic activity, whose size, shape and distribution infect its properties. Therefore, in order to prepare a composite electrode with high activity, the special nano Pt-TiO₂/Ti composite structure was prepared by anodic oxidation- electrodeposition with ultrasonics, and characterized properties in this work.Firstly, TiO₂ naotubes were gained on the substrate by constant voltage anodic oxidation with the hydrofluoric acid as electrolyte. Then nano-Pt coating was deposited on the TiO₂ naotubes by constant current electrodecomposition with the chloroplatinic acid as electrolyte .The morphology and the structure of TiO₂ naotubes and nano-Pt coating were observed and analysed respectively with the aid of FESEM and XRD. The effects of the anodization parameters on the morphology and crystal structure of TiO₂ nanotubes and the electrodeposition parameters on the morphology and crystal structure of nano Pt were respectively investigated. It was indicated that the tidiest TiO₂ nanotubes were obtained on the pure titanium at 20V voltage and 25 minutes oxidation time; when the electrolyte was low in concentration or the depositing current was small, the as-deposited Pt appeared mostly in particles, and tended to be changed in flower structures or plexi structures with the increasing of the current or the deposition time. Meanwhile, the composite electrode with the upper layer of Pt and the lower structure of TiO₂ nanotubes was prepared by depositing with ultrasonicassisted.Moreover, Pt-TiO₂/Ti composite structure was characterized respectively by CV and polarization curve in the 0.5mol/L sulfuric acid and 0.5mol/L methanol mixed with sulfuric acid. The results showed that the electrocatalytic activitics and the stability of the composite electrode for the methanol oxidation were better than those of Pt electrode and Pt/Ti electrode. And the electrode possessed the best properties prepared at the 5mA/cm2 current density in the 1.0g/L electrolyte for 1 minute.更多还原