Preparation and Performance of Ag3PO4/Ag2S/g-C3N4 Composite Photocatalyst
邓军阳 湖北工业大学材料与化学工程学院, 武汉 430068  
汪杰 湖北工业大学材料与化学工程学院, 武汉 430068  
朱思龙 湖北工业大学材料与化学工程学院, 武汉 430068  
聂龙辉 湖北工业大学材料与化学工程学院, 武汉 430068 
摘要: 通过沉积法和离子交换法成功地制备了Ag3PO4/Ag2S/g-C3N4复合型光催化剂。利用X射线多晶粉末衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)、N2吸附-脱附等温线、紫外-可见漫反射光谱、荧光光谱等手段对样品进行了表征。通过降解罗丹明B考察其可见光催化活性及稳定性,研究了硫化钠与磷酸银物质的量的比值(nNa2S/nAg3PO4)、g-C3N4添加量对所制备复合光催化材料性能的影响,同时对光催化机理进行了探讨。结果表明,随着nNa2S/nAg3PO4的增加,所得复合催化材料活性先增加后降低;当nNa2S/nAg3PO4为1.5%、g-C3N4与Ag3PO4的质量比为3:7时制备的催化剂ASC1.5的光催化活性最好,在可见光照射下,40 min内可将罗丹明B完全降解,且5次循环使用后仍保持较高的催化活性。和Ag3PO4相比,Ag3PO4/Ag2S/g-C3N4复合型光催化材料的活性与稳定性都得到明显提高,这主要归因于复合催化剂比表面积和孔结构的增加,载流子分离效率的提高。光催化机理研究表明,空穴(h+)、超氧阴离子自由基(·O2-)和羟基自由基(·OH)都是光催化过程中的主要活性物种。三者作用大小依次为:h+ > ·O2- > ·OH。
关键词: Ag3PO4  g-C3N4  Ag2S  光催化  可见光
基金项目: 国家自然科学基金(No.51572074)和湖北省绿色轻质材料重点实验室开放课题(No.201710A12)资助。
Abstract: Ag3PO4/Ag2S/g-C3N4 composite photocatalysts were successfully prepared by a deposition-ion exchanged combined method. And the obtained samples were characterized by X-ray powder diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), N2 adsorption and desorption isotherms, UV-visible diffuse reflectance spectroscopy, fluorescence spectrophotometry and so on. The catalytic activity and stability of the catalysts were evaluated by degradation of rhodamine B under visible light. The effect of molar ratio of sodium sulfide to silver phosphate (nNa2S/nAg3PO4) on the photocatalytic performance of the silver phosphate was studied. In addition, the photocatalytic mechanism was also investigated. The results show that, with the increase of nNa2S/nAg3PO4, the activity of the obtained composite catalytic material increased firstly and then decreased. When nNa2S/nAg3PO4 was 1.5%, the obtained ASC1.5 catalyst could completely degrade rhodamine B within 40 min under visible light irradiation, and also maintained high activity after five-cycle use. Compared with single silver phosphate, the activity and stability of Ag3PO4/Ag2S/g-C3N4 composite photocatalytic materials were significantly improved, which was mainly attributed to the increase of surface area and the presence of porous structure that enhanced separating efficiency of electron-hole pairs. The study of photocatalytic mechanism over the composite catalyst have shown that h+, ·O2- and ·OH were the main active species in the photocatalytic process. The order of the role of the above three species was:h+ > ·O2- > ·OH.
Keywords: Ag3PO4  g-C3N4  Ag2S  composite catalyst  photocatalysis  visible light
投稿时间:2019-02-14 修订日期:2019-04-08
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