Ag_3PO_4/BiVO_4复合光催化剂的制备及可见光催化降解染料(英文)

结合回流法和原位沉淀法成功制备磷酸银/矾酸铋(Ag3PO4/BiVO4)复合光催化剂.通过X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、能量色散X射线光谱(EDS)、紫外-可见漫反射光谱(UV-Vis DRS)及光致发光(PL)光谱对制备样品进行表征.XRD和FESEM结果表明成功制备Ag3PO4/BiVO4复合光催化剂.采用节能发光二极管灯(LED)作为可见光光源,在低消耗光催化系统中评价制备样品可见光催化降解染料的活性.当Ag3PO4和BiVO4的组成摩尔比为1:3时,复合Ag3PO4/BiVO4光催化剂呈现出高于纯相Ag3PO4的催化活性,可减少Ag3PO4的使用量.Ag3PO4/BiVO4复合光催化剂在中性溶液中表现出高活性,同时证实其对阳离子染料的光催化降解效果强于阴离子染料.在Ag3PO4/BiVO4系统中,超氧自由基和空穴是主要的活性物种.经过三次循环利用,Ag3PO4/BiVO4复合催化剂的可见光催化活性表现出不同程度的降低,归因于降解过程中产生金属银.

Synthesis of Ag3PO4/BiVO4 Composite Photocatalyst and Its Photocatalytic Degradation of Dyes under Visible Light Irradiation

Silver phosphate/bismuth vanadate (Ag₃PO₄/BiVO₄) composite photocatalysts were successfully synthesized by coupling a reflux method with an in situ precipitation route. X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), UV-Vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy were used to characterize the as-prepared products. The XRD and FESEM results showed that Ag₃PO₄/BiVO₄ composite photocatalysts were successfully obtained. An energy-efficient light emitting diode lamp was used as the visible light source, and the photocatalytic performances of the as-synthesized products were evaluated for dye degradation in a low-cost photocatalytic system. The Ag₃PO₄/BiVO₄ composite with a Ag₃PO₄:BiVO₄ molar ratio of 1:3 exhibited much higher photocatalytic activity than pure Ag₃PO₄ catalyst, resulting in decreased use of Ag₃PO₄. The Ag₃PO₄/BiVO₄ composite photocatalyst showed the best photoactivity in neutral solution and had a higher photodegradation rate for cationic dyes than anionic dyes. The superoxide radicals (O₂^-·) and holes (h+) were considered to be the main active species in the Ag₃PO₄/BiVO₄ system. The photocatalytic activity of the Ag₃PO₄/BiVO₄ composite photocatalyst decreased to different degrees after three cycles because of the production of metallic silver.