溶剂热法制备BiOI/BiOCl异质结及其光催化性能研究

Study on Preparation and Optical Properties of BiOI/BiOCl Heterojunction Photocatalytic Materials by Solvothermal Methods

以五水合硝酸铋、氯化钠、碘化钾为主要原料,以乙二醇为溶剂,采用一步溶剂热法制备了BiOI/BiOCl异质结光催化材料。研究了反应温度、反应时间、掺杂比例对材料光催化性能的影响。通过扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外可见分光光度计、紫外可见漫反射(UV-Vis DRS)等测试手段对样品的形貌、物相组成、表面化学态、光催化性能进行了表征。结果表明当碘的含量为20%,在140℃的温度下反应3 h所制备的BiOI/BiOCl异质结光催化材料可见光催化降解罗丹明B的效果最好,120 min后达到了95.46%,是纯BiOCl的9.5倍。提出了S-型半导体光催化机理,该机理促进了光生电子空穴对的分离,保留了较高的氧化还原能力,提高了光催化性能。

BiOI/BiOCl heterojunction photocatalytic materials were prepared by solvothermal method using bismuth nitrate pentahydrate,sodium chloride and potassium iodide as raw materials and glycol as solvent.The effects of reaction temperature,reaction time and doping ratio on the photocatalytic properties of the materials were studied.The morphology,phase composition,surface chemical states and photocatalytic properties of the samples were characterized by SEM,XRD,XPS and Uv-vis spectrophotometer.The asprepared 20%BiOI/BiOCl which was prepared by reaction at 140℃for 3 h could degrade 95.46%RhB within 120 min under visible-light irradiation,the RhB degradation efficiency was 9.5 times than that of individual BiOCl samples.The photocatalytic mechanism of S-type semiconductor was proposed.The internal electric field expedited the separation efficiency of photogenerated carriers,retained the higher oxidation and reduction,so the photocatalytic efficiency was improved significantly.