Hg掺杂CdS的制备及可见光降解有毒有机污染物

采用镉硫共沉淀方法制备了Hg掺杂CdS(Hg_xCd_1-xS)光催化剂,运用X射线衍射法(XRD)、X射线光电子能谱(XPS)、透射电镜(TEM)和紫外-可见吸收光谱对所制备的催化剂进行了表征;利用可见光催化降解罗丹明B(Rhodi-amine B,RhB)和2,4-二氯苯酚(2,4-dichlorophenol,2,4-DCP)为探针反应,对Hg_xCd_1-xS可见光催化活性进行了研究,通过跟踪RhB降解过程中吸收光谱的变化和总有机碳(TOC),评价了Hg_xCd_1-xS对有机物的氧化降解及深度矿化能力.结果表明:Hg_xCd_1-xS催化剂为立方晶型,Hg的最佳掺杂量为5%,其禁带宽度约为2.15 eV,对RhB和2,4-DCP均有较好的降解效果,实验条件下30 min RhB褪色率为100%,RhB的30 h矿化率为45.5%,2,4-DCP的16 h降解率达55%.Hg_xCd_1-xS可见光光催化降解RhB具有较高的稳定性,Hg的掺杂能有效降低CdS光腐蚀问题.通过ESR跟踪测定光催化反应过程中产生的自由基,表明降解过程涉及·OH机理.

Preparation of Hg-Doped CdS and Degradation of Toxic Organic Pollutants under Visible Light Irradation

Mercury doped CdS nanoparticles was prepared by co-precipitation method.The doped CdS nanoparticles were characterized by X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscope(TEM) and UV-Vis spectrum.The photo-catalytic degradation of Rhodamine B(RhB) and 2,4-dichlorophenol(2,4-DCP) under visible light were used as probe reactions to evaluate photo-catalytic activities by tracing the UV-Vis spectrum and the total organic carbon(TOC) changes.The results indicated that the best mole rate of Hg was 5% of the total metal amounts with the cubic phase crystal,and the band gap of Hg0.05Cd0.95S was 2.15 eV.In 30 minutes,the decolouration of RhB was 100% and the mineralization ratio of RhB was 45.5% in 30 hours,the mineralization of 2,4-DCP was up to 55% in hours with a high stability,the dop of the Hg can efficiently inhibit the photo-corrosion of CdS.The mechanism of degradation were evaluated by electron spin resonance(ESR),the findings showed that the degradation process involved hydroxyl radical course.