阴极直接制备铜氧化物-SiO_(2)复合薄膜及其电化学形成机理

Direct Electrodeposition and Chemical Formation Mechanism of Copper Oxide-Silica Composite Thin Films

以室温下制备出的n_(Cu)^(2+)∶n_(Cit)^(3-)=2∶1的透明稳定的Cu(Ⅱ)-Cit^(3-)-SiO_(2)复合溶胶为电解液,直接在氧化铟锡导电玻璃(ITO)阴极上电沉积得到铜氧化物-SiO_(2)复合薄膜。循环伏安(CV)和X射线衍射(XRD)结果表明,溶胶中Cu^(2+)与吸附在电极上的SiO_(2)溶胶共电沉积形成Cu_(2)O-SiO_(2)凝胶薄膜,XRD和计时安培(CA)结果表明,薄膜中的SiO_(2)量随过电位升高而减少。X射线光电子能谱(XPS)、XRD和能量色散X射线(EDX)结果表明,高过电位下,SiO_(2)和Cu(Ⅱ)借助析氢生成的OH-共沉积,得到CuO/Cu_(2)O-SiO_(2)薄膜,这与扫描电子显微镜(SEM)图片显示的所得薄膜具有两种不同形貌的颗粒的结果一致。

Composited thin films of copper oxide-silica were electrodeposited directly on an ITO substrate at room temperature using Cu(II)-Cit^(3-)-SiO_(2)sol with n_(Cu)^(2+)∶n_(Cit)^(3-)of 2∶1 as a electrolyte. Cyclic voltammetry(CV)and X-ray diffraction(XRD)results indicate that Cu_(2)O-SiO_(2)gel films are formed by copper ions co-deposition with SiO_(2) sol adsorbed on electrode. The adsorbed amount of SiO_(2) sol on the ITO electrode decreased with the increases of overpotentials. XRD and chronoamperometric(CA)results show that the adsorption amount of SiO_(2) in the film decreases with the increase of the overpotential. The results of X-ray photoelectron spectroscopy(XPS), XRD and energy dispersive X-ray(EDX)showed that CuO/Cu_(2)O-SiO_(2) films were obtained at higher overpotentials, which was consistent with the results of particles with two different morphologies in the films obtained by scanning electron microscopy(SEM). The CuO/Cu_(2)O-SiO_(2) films are formed by the co-deposition of SiO_(2) and Cu(II)with OH generated by hydrogen evolution.