新型复合CdIn_(2)S_(4)/ZnIn_(2)S_(4)异质结的制备及其光催化性能

Preparation and photocatalytic properties of novel composite CdIn_(2)S_(4)/ZnIn_(2)S_(4) heterojunction

探索高效、稳定的光催化剂是实现实用化太阳能光催化降解污染物的永恒追求。采用化学共沉淀法合成了CdIn_(2)S_(4)/ZnIn_(2)S_(4)微球,然后500 ℃退火得到降解性能更好的CdIn_(2)S_(4)/ZnIn_(2)S_(4)异质结。SEM、XRD、XPS、BET和UV-Vis DRS对样品进行了表征。观察到异质结外貌为球形,具有典型的介孔结构,表面光电流响应和阻抗测试结果显示其活性显著增强。在光催化降解亚甲基蓝的反应中,退火后的CdIn_(2)S_(4)/ZnIn_(2)S_(4)异质结的光催化活性最佳。反应90 min后,亚甲基蓝(MB)的降解率为96.7%。活性的提高可以归因于催化剂对可见光吸收的增强和光生电荷分离效率的提高。对照实验证明,降解体系中产生的活性物种·O_(2)^(-)在降解过程中起关键作用。预测了异质结光催化降解污染物的机制。本研究合成的复合CdIn_(2)S_(4)/ZnIn_(2)S_(4)异质结对制备高效光催化材料具有借鉴意义,并展示了其在降解污染物方面的良好实用性。

Exploring efficient and stable photocatalysts is an ongoing pursuit in effective solar photocatalytic degradation of pollutants.Through a chemical coprecipitation method,CdIn_(2)S_(4)/ZnIn_(2)S_(4) microspheres were synthesized and then further annealed at 500℃to obtain a CdIn_(2)S_(4)/ZnIn_(2)S_(4) heterojunction that showed greater degradation performances.Characterizations of the samples through SEM,XRD,XPS,BET and UV-Vis DRS determined that the heterojunction had the spherical appearance and typical mesoporous structure.The surface photocurrent response and EIS showed significantly enhanced catalytic activity.CdIn_(2)S_(4)/ZnIn_(2)S_(4) heterojunction catalysts displayed the best photocatalytic activity in the degradation of methylene blue(MB)after 90 min of illumination,yielding a degradation rate of 96.7%.Enhancement of photocatalytic activity is attributed to the increase of visible light absorption and excellent separation ability of h^(+)-e^(−) pair.A control experiment revealed that the active species•O_(2)^(−)played a significant role in the degradation process.Based on these findings,a mechanism for the photocatalytic degradation of pollutants via CdIn_(2)S_(4)/ZnIn_(2)S_(4) heterojunction was predicted.The composite CdIn_(2)S_(4)/ZnIn_(2)S_(4) heterojunction synthesized in this study has reference significance for the preparation of high-efficient photocatalytic materials,and shows its good practicability in the degradation of pollutants.