电化学氧化生长纳米晶TiO_2光催化薄膜结构与性能表征

CHARACTERISTICS AND PROPERTY OF PHOTO-CATALYTIC NANO CRYSTALLINE TITANIUM DIOXIDE FILM PREPARED BY ELECTROCHEMICAL OXIDATION

用电化学阳极氧化方法在Ti上制备纳米晶TiO2 薄膜 .结果表明 ,将工业纯钛片暴露于电介质溶液并加一定电压 ,Ti表面将氧化生长TiO2 薄膜 .适当控制氧化电压、溶液温度 ,可以得到非晶氧化膜 ,再进行控制条件下的晶化处理 ,得到锐钛矿相纳米晶TiO2 薄膜 ,其晶粒度约在 10～ 30nm .研究了电化学氧化过程氧化膜生长动力学 ,发现在 0～ 80V电压范围内 ,氧化膜随电压增加而增厚 ,在一定电压下氧化膜有一恒定的厚度 ,氧化膜厚度和氧化电流随时间而逐步降低呈对数规律 ,氧化膜生长过程受电场作用下离子通过膜的迁移所控制 .用TEM、X -衍射表征TiO2 薄膜的晶体形貌与相结构 .用光谱仪测定了薄膜对入射光的吸收特性 ,表明电化学氧化制备的纳米晶TiO2 薄膜对近紫外入射光产生强烈的吸收 ,显示纳米结构的量子效应 .

Photo-catalytic titanium dioxide film in nano crytalline has been prepared by electrochemical oxidation process.It shows that amorphous titanium dioxide films are formed during the electrochemical oxidation process in the studied solution and applied voltage.Then heat treatment is carried out on the formed amorphous film to form nano crystallized titanium dioxide film under the controlled temperature and heating time.The oxidation kinetics has been studied by measuring the film thickness and current density with oxidation time respectively.It shows that the film grows to an equilibrium thickness under certain oxidation voltage and the equilibrium thickness increases with the applied voltage.The oxidation current density decreases with time in logarithm law under the applied voltage range from 0 to 80 V.The film crystalline size ranges from 10～30 nm and the film phase structure can be pure anatase as demonstrated by TEM and X-ray diffraction after the crystallization treatment.The photo absorption measurement demonstrated that the prepared film shows very strong absorption to the incoming light of near ultraviolet wave range.