钛基二氧化锡电极电解过程中羟基自由基检测及电催化机理

Detection of Hydroxyl Radicals During Electrolysis of Ti/SnO_2 Electrode and Analysis of the Electrocatalytic Mechanism

采用浸渍-热分解方法制备了钛基二氧化钌(Ti/RuO2)和钛基二氧化锡(Ti/SnO2)两类尺寸稳定阳极电极。以扫描电子显微镜(SEM)和X射线衍射(XRD)对电极结构进行了表征。用循环伏安法(CV)比较研究了Ti/RuO2和Ti/SnO2电极直接电催化氧化苯酚性能,表明苯酚在Ti/RuO2和Ti/SnO2电极上均可发生直接电氧化反应,两种电极上氧化峰电位分别为0.96和1.43 V(vs.Ag/AgC l)。以对苯二甲酸为捕获剂,利用荧光光谱法进行了羟基自由基(.OH)检测。Ti/SnO2电极在电解过程中能够产生.OH;而Ti/RuO2电极.OH的生成极其微弱。Ti/SnO2电极电解过程中生成.OH是其具有高电催化活性的主要原因,也表明了用荧光法进行羟基自由基检测方便、灵敏,可以用于电催化过程羟基自由基的检测。

Ti base ruthenium dioxide electrode （Ti/RuO2 ） and Ti base tin dioxide electrode （Ti/SnO2 ） electrode were prepared by dlpping-pyrolysis methods and scanning electron microscopy and X-ray diffraction （XRD） analysis were used to analyze the structure of the two anodes. Cyclic voltammetry （CV） was used to evaluate the capacity of direct electro-catalytic oxidation of phenol by the Ti/RuO2 and Ti/SnO2 electrodes. The results exhibited that phenol could be directly electro-oxidized both on the Ti/RuO2 and Ti/SnO2 electrode, whose oxidation peaks lies about 0. 945 V and 1.40 V （vs. Ag/AgCl） , respectively. Taking terephthalic acid as hydroxyl radical （· OH） capture agent, fluorescence spectrum technique was employed to examine whether · OH could be produced during the electrochemical degradation process or not. The results proved that ~ OH was produced on the Ti/SnO2 electrode during the degrading process and the quantity of · OH was produced in the direct ratio of the time. However, there was almost no · OH being detected on the Ti/RuO2 electrode. It was the production of · OH that makes the Ti/SnO2 electrode higher electro-chemical activities. And also, it was further proved that fluorescence method, which possesses convenience, and efficiency, could be used in · OH detection during electrochemical degradation process.