摘要
真空蒸镀法结合溶胶凝胶法成功地制备Cu-TiO23层复合结构薄膜。运用XRD,SEM,UV-vis等手段进行结构表征和光吸收性能测试。通过模拟可见光下制备样品对亚甲基蓝溶液降解率的变化,评定其光催化活性。结果表明:该法制备的复合结构薄膜,在未热处理时真空蒸镀的金属层为单质Cu。在723 K热处理后,沉积的Cu被氧化主要以Cu2O的形式存在,而TiO2为单一的锐钛矿晶型。823 K保温2.0 h热处理后Cu2O进一步被氧化为CuO,同时出现了少量金红石型TiO2。由于Cu2O与CuO均为窄带隙的半导体,在可见光照射下会发生电子由价带向导带的跃迁,因此复合薄膜表现出明显的可见光吸收性能。降解实验的结果则表明:不同温度热处理后的复合薄膜均表现出较高的光催化活性,特别是723 K热处理后的复合薄膜样品可见光催化活性最好,在可见光照射5.0 h后对亚甲基蓝溶液降解率接近100%。分析其原因认为,p型的Cu2O和CuO与n型TiO2半导体接触后,在其界面形成了纳米异质结的结合,其p-n结的内建电场抑制了光生载流子的再复合,提高了量子产率,因此使复合薄膜表现出较高的光催化性能。
Cu-doped TiO2 films were prepared by sol-gel and high vacuum evaporate plating technology.The composite film was characterized by XRD（X-ray diffraction）,SEM（scanning electron microscopy）,and UV-vis（UV-vis absorption spectra）.The visible-light catalytic activity of composite film was evaluated by degradation of methylene blue in simulated visible light.Results show that the metal layer of composite films contained Cu as components at untreated.Cu2O as a major component and TiO2 showed single anatase phase at 723 K.Heat treatment at 823 K for 2.0 h the composite film transformed into a CuO/TiO2 composite,small amount rutile phase appeared.Cu2O and CuO both were narrow gap semiconductor,and excited electronic transited from value band to conduction band in visible light.So the composite film presented significant visible light absorption.Degradation results showed the composite film at different temperature treatment exhibited high visible-light catalytic activity.Especially the composite film of treated at 723 K the degradation of methylene blue was close to 100 % under visible light irradiation for 5.0 h.Analysis suggested that Cu2O and CuO were p-type semiconductor,TiO2 was n-type semiconductor.They formed nano-heterojunction in composite film.The built-in electric field of p-n junction inhibited further combination of photo-generated carrier and improved quantum yield,which showed higher visible-light catalytic activity.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2011年第4期510-514,共5页
Chinese Journal of Rare Metals
基金
山西省重点实验室开放基金(2008012013-7)
山西省归国留学基金(2007-25)
太原市2009年大学生创新创业专项项目(09122018)资助
关键词
铜沉积
复合薄膜
异质结
可见光催化活性
Cu-doped
composite film
heterojunction
visible-light catalytic activity
