ZnxCd1-xS的共沉淀法制备及其光催化活性研究

利用共沉淀一步法在常温下合成具有高光催化活性的Zn_xCd_1-xS固溶体光催化剂,用XRD、SEM、XPS、BET、UV-VIS DRS和PL对制备出的Zn_xCd_1-xS样品进行结构和光学性能的表征,并在模拟太阳光照射下对罗丹明B（RhB）溶液进行降解,评价其光催化活性。结果表明,Zn_xCd_1-xS对可见光的吸收阀值随Zn含量增加而减少,禁带宽度随之增大;颗粒状Zn_xCd_1-xS固溶体对罗丹明B具有较高的光催化活性,其中Zn_0.8Cd_0.2S的光催化性能最优,在90 min内对RhB的降解率达到98.5%,远高于CdS和ZnS光催化剂;经过4次重复使用后,Zn_0.8Cd_0.2S对RhB的降解率维持在75%以上。Zn_0.8Cd_0.2S的比表面积和孔隙体积相对于CdS分别增至154.6 m²/g和0.40 cm³/g,其光催化活性显著增强的主要原因是由于其较高的光生电子空穴对的分离效率及较低的复合率。

ZnxCd1-xS PREPARED BY COPRECIPITATION METHOD AND ITS PHOTOCATALYTIC ACTIVITY

Zn_xCd_1-xS solid solution photocatalysts with high photocatalytic activity were prepared by the coprecipitation one-step method at room temperature. The structural and optical properties of the as-prepared samples were characterized by XRD, SEM, XPS, BET, UV-VIS DRS and PL. Photocatalytic activity of the samples was evaluated via degrading the Rhodamine B solution under simulated sunlight. The results show that the visible light absorption threshold of Zn_xCd_1-xS decreases with the increase of Zn, while the band gap increases gradually. Moreover, the granular Zn_xCd_1-xS exhibits excellent photocatalytic activity for the degradation of Rhodamine B, and Zn_0.8Cd_0.2S has the best photocatalytic performance among the as-prepared samples. The degradation rate of Zn_0.8Cd_0.2S for Rhodamine B reaches 98% within 90 min, which is much higher than that of CdS and ZnS. After four recycles, the RhB degradation is still more than 75%. Compared with CdS, the specific surface area and pore volume of Zn_0.8Cd_0.2S increase to 154.6 m²/g and 0.40 cm³/g, respectively. The main reasons for the enhanced photocatalytic activity are the effective separation efficiency of photogenerated electron-hole pairs and the lower recombination rate.