Cd空位缺陷的CdS光催化降解罗丹明B

Photocatalytic degradation of RhB by CdS with Cd vacancy defects

为提高CdS光催化降解性能,通过水热法合成了具有Cd空位缺陷的Cd_(1-x)S,并将其应用于光催化降解罗丹明B(RhB).结果表明,可见光照射下反应40min后,Cd_(1-x)S对RhB的光降解率达到98.1%,降解速率常数k=0.08649min^(-1),光催化活性远高于CdS.自由基淬灭实验结果表明,·O_(2)-为Cd_(1-x)S光催化降解RhB的主要活性物种.UV-vis、XPS、EPR表征结果表明,Cd空位的引入拓宽了Cd_(1-x)S的带隙宽度,抑制了可见光的吸收,证明了Cd_(1-x)S活性的提升并非源于能带结构的改变.密度泛函理论计算结合PL表征表明,Cd空位的引入导致了CdS局域电子密度不对称,促进空穴传输和载流子分离,从而显著提高了Cd_(1-x)S的光催化活性.

To enhance the photocatalytic degradation performance of CdS,Cd_(1-x)S with Cd vacancy defects was synthesized through a hydrothermal method and was applied to the photocatalytic degradation of Rhodamine B(RhB).The results showed that under visible-light irradiation for 40min,the photodegradation rate of RhB by Cd_(1-x)S reached 98.1%,with a degradation rate constant k=0.08649min^(-1),which was significantly higher than that of CdS.The quenching experiments of free radicals indicated that·O_(2)-is the main active species during the photocatalytic degradation of RhB by Cd_(1-x)S.UV-DRS,XPS,and EPR characterization results demonstrated that the introduction of Cd vacancies widened the bandgap of Cd_(1-x)S to inhibit the absorption of visible light,and proved that the enhancement of the photocatalytic activity was not due to changes in the band structure.Density functional theory calculations combined with PL results revealed that the introduction of Cd vacancies led to an asymmetric local electron density in CdS to promote hole transport and charge carrier separation,thereby significantly enhancing the photocatalytic activity of Cd_(1-x)S.