一步溶剂热法合成溴化银/磷酸银复合催化剂及其可见光催化性能

Synthesis and photocatalytic properties of AgBr/Ag_3PO_4 hybrids by one-step solvothermal method

以十六烷基三甲基溴化铵(CTAB)为溴源,以乙二醇和水为混合溶剂,采用溶剂热法一步合成溴化银/磷酸银(Ag Br/Ag3PO4)复合物。利用X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱(UV-Vis DRS)、荧光分光光度计(PL)等方法对复合物的结构和形貌进行分析。以水中微污染物甲基橙(MO)的降解效果来评价溴化银/磷酸银复合物的可见光催化活性及光催化降解机理。结果表明,在可见光照射8 min后,0.08 g的溴化银/磷酸银复合物(溴与磷的质量比为40%)对甲基橙溶液(200 m L,8 mg/L)的降解率达到99.52%,是相同条件下以纯水为溶剂制备复合物样品对甲基橙降解率的1.8倍,且循环使用3次后还具有高的稳定性。在光催化降解过程中,溴化银和磷酸银的光生电子-空穴对有效分离,同时负载在溴化银和磷酸银表面的银纳米粒子可作为电子捕获陷阱使得溴化银/磷酸银具有高的催化活性。

AgBr/Ag_3PO_4 compound was synthesized via one-step solvothermal method using CTAB as Br precursor,and its structure and morphology were characterized by X-ray diffraction（XRD）,field emission scanning electron microscopy（FE-SEM）,X-ray photoelectron spectroscopy（XPS）,UV-vis diffuse reflectance spectroscopy（UV-Vis DRS） and photoluminescence（PL）.The visible light photocatalytic activity and photocatalytic degradation mechanism of AgBr/Ag_3PO_4 compound were evaluated by the degradation effect of methyl orange（MO） in water.Under visible light of 8 min,0.8 g AgBr/Ag_3PO_4 compound（mass ratio of Br to phosphate radical was 40%） degraded methyl orange（MO, 200 m L,8 mg/L） efficiently and displayed much higher（1.8 times） photocatalytic activity than that of AgBr/Ag_3PO_4 that was synthesized by pure water solvent,the degradation rate was 99.52%.Moreover,it retained high stability after 3 cycles.The photocatalytic activity enhancement of AgBr/Ag_3PO_4 was closely related to the efficient separation of electron-hole pairs derived from the matching band potentials between AgBr and Ag_3PO_4,as well as the good electron trapping role of Ag nanoparticles in situ formed on the surfaces of AgBr and Ag_3PO_4 particles during the photocatalytic reaction.