采用直流反应磁控溅射的方法在普通玻璃上沉积得到Cu2O、TiO2和Cu2O/TiO2复合薄膜. 用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和X射线能谱仪(EDS)对薄膜的晶体结构、表面形态和薄膜元素组成进行了分析. XRD结果表明, 当反应溅射时间为5 min时, Cu2O薄膜由单一的(111)晶面组成; 反应时间的延长促进了Cu2O(110)和(220)晶面的生长. 通过计算得出Cu2O(111)更有利于对O2的吸附. 进一步使用氙灯作为光源, 用薄膜对亚甲基蓝(MB)的降解率来表征光催化活性. 结果表明, Cu2O/TiO2复合薄膜的光催化效果随着Cu2O含量的增加升高而后降低, 当Cu2O含量为2.6mol%时, 光催化活性最高. 光催化效率的提高主要归因于Cu2O的加入引起光生电子-空穴的分离, 而过量的Cu2O会延长光生电子迁移到Cu2O/TiO2界面和空穴迁移至表面所需要的时间, 使电子和空穴复合的几率增大, 从而降低了量子效率.
Cu2O, TiO2 and composite Cu2O/TiO2 films were deposited on slide glass by direct current (DC) reactive magnetron sputtering. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy-dispersive spectrometry (EDS) were applied to characterize crystal structure, morphology and composition of the films, respectively. Photocatalytic activity was evaluated by the degradation of methylene blue (MB) with Xenon lamp. XRD results show that besides the initial (111) crystal plane at sputtering time of 5 min, (110) and (220) crystal planes gradually develop on the Cu2O film with the increase of sputtering time. Our calculation result indicates that (111) crystal plane is more beneficial to absorption of O2 than other crystal planes. The photocatalytic activity of the Cu2O/TiO2 composite films first increases with increasing Cu2O-deposited content, and then reaches the highest value when the deposited content of Cu2O is 2.6mol%, and successively undergoes a drop. The enhancement of the photocatalytic activity is mainly attributed to alleviate the recombination of electron-hole pairs. Excessive Cu2O will prolong the time for transferring of electrons to Cu2O/TiO2 interface and holes to surface, which increases the recombination probability of electrons and holes, and thus reduces the quantum efficiency.
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