CdS修饰TiO_2纳米带制备及光催化降解有毒有机污染物

以硫酸钛为原料,在210℃低温下,水热制备Ti O2纳米带.通过沉淀法用CdS修饰Ti O2纳米带表面,制得Ti O2@CdS复合光催化剂,采用XRD、TEM和反射紫外对其结构及光化学特性进行初步表征.以可见光(λ≥450 nm)光催化降解罗丹明B(Rhodamine B,RhB)、水杨酸(Salicylic Acid,SA)及2,4-二氯苯酚(2,4-Dichlorophenol,2,4-DCP)为探针反应,研究反应温度、介质和负载CdS对Ti O2@CdS结构性能的影响.结果表明,所制备的Ti O2纳米带分散性好.复合粉末由锐钛矿相Ti O2和立方相CdS组成.常温25℃中性介质中用CdS修饰的Ti O2的活性,在可见光照射下,为单纯Ti O2纳米带的29倍.同时,Ti O2也促进了CdS可见光光催化活性的提高.通过跟踪降解体系紫外-可见光谱(UV-vis)、红外光谱(FTIR)和总有机碳(TOC)测定,结果发现Ti O2@CdS/vis体系在pH7.0时,对SA的降解率较Ti O2纳米带有显著地提高,反应15 h和21 h后,RhB和2,4-DCP的矿化率分别可达到47.8%和30.8%.

Preparation of CdS-modified TiO2 Nanoribbon and Photocatalytic Degradation of Toxic Organic Pollutants

TiO2 nanoribbon was synthesized by the hydrothermal method at 210 ℃ using titanium sulfate as the raw material.TiO2@CdS composite photo-catalyst was synthesized by modifying TiO2 surface with CdS through the precipitation method.The structure of TiO2@CdS powders were characterized by X-ray diffraction(XRD),transmission electron microscope(TEM) and UV-Vis absorption spectral techniques.The photo-catalytic activity of TiO2@CdS was studied using photocatalytic degradation of Rhodamine B,Salicylic Acid and 2,4-dichlorophenol(2,4-DCP) under visible light(λ≥450 nm) as the probe reactions.The effects of the reaction temperature,medium and CdS loading on the structural properties of TiO2@CdS were investigated.The results showed that the prepared TiO2 nanoribbon had good dispersivity.Composite nanocrystalline particle was composed of TiO2 with anatase crystalline structure and CdS with zinc-blend crysatalline structure.At room temperature(25 ℃),the activity of TiO2 decorated with CdS in neutral medium was enhanced by 29 times as compared with pure TiO2 under the visible light irradiation.Therefore,the photo-activity of CdS was improved by TiO2.In TiO2@CdS/Vis system,the photodegradation of Salicylic Acid(SA) over TiO2@CdS was much promoted compared with pure TiO2 nanoribbon.The mineralized rates of Rhodamine B(RhB) and 2,4-dichlorophenol(2,4-DCP) reached 47.8% and 30.8% after 15 and 21 hours respectively at pH 7.0.