复合半导体光催化剂p-CoO/n-CdS的制备、表征及光催化性能

以醋酸镉、十二硫醇、硬脂酸和醋酸钴等为原料,采用新方法制备了CdS和一系列p-CoO/n-CdS复合半导体光催化剂.用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、N2吸附-脱附和紫外-可见漫反射光谱(UV-Vis DRS)等对产物进行了表征.结果表明,p-CoO/n-CdS复合半导体中,CoO粒子紧密结合在CdS颗粒上,CdS的颗粒粒径在100 nm左右,为六方纤锌矿晶型,CoO的颗粒粒径在10 nm左右,颗粒粒径分布均匀.p-CoO/n-CdS的UV-Vis DRS分析结果表明,在400-550 nm范围内都有一强吸收带,属于CdS在可见光区的特征吸收.用光催化降解甲基橙测试了光催化性能,结果表明,p-CoO/n-CdS光催化活性是CdS光催化活性的2.2倍左右.光腐蚀测试结果表明,CdS的光腐蚀速率是p-CoO/n-CdS中CdS光腐蚀速率的2倍以上,说明CoO与CdS复合对CdS的光腐蚀具有明显的抑制作用.

Preparation,Characterization and Photocatalytic Property of p-CoO/n-CdS Compound Semiconductor Photocatalyst

The photocatalysts CdS and p-n coupled semiconductor photocatalysts CoO/CdS(p-CoO/n-CdS) were prepared using cadmium acetate, lauryl mercaptan, cobalt acetate, and stearic acid by a new method. The structural and optical properties of CdS and p-CoO/n-CdS were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM),N₂ adsorption -desorption, and ultraviolet -visible diffuse reflection spectroscopy (UV-Vis DRS). The results showed that the particles of CoO compactly connected with the particles of CdS in the p-CoO/n-CdS. The particle size of CdS was about 100 nm and the crystalloid of CdS was hexagon spiauterite. The particle size of CoO was about 10 nm, and the distribution of particles size was uniform. The results of UV-Vis DRS showed that the nano-CdS particles could absorb the visible light at wavelengths between 400 and 550 nm which is characteristic absorption of CdS in the visible region. The photocatalytic activity of the photocatalyst was evaluated by photocatalytic degradation of methyl orange (MO). The results showed that the photocatalytic activity of p-CoO/n-CdS was much higher, which was 2.2 times than that of CdS on the photocatalytic degradation of methyl orange. The results of photocorrosion test showed that the photocorrosion rate of CdS was two or more times than that of p-CoO/n-CdS, which indicated that CoO coupled with CdS could effectively restrain the photocorrosion of CdS.