一步醇-水热法合成高效的F掺杂BiVO4光催化剂

摘要

以NH4F为掺杂前体,采用简单的一步醇-水热法制备了F掺杂BiVO4光催化剂.利用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱(UV-Vis)和光致发光光谱(PL)表征了这些光催化剂的物理化学性质.在少量H2O2存在条件下,以可见光照射下光催化降解苯酚的反应测定了这些光催化剂的催化活性.研究表明,相较于未掺杂的BiVO4样品而言,F掺杂BiVO4样品不仅仍保留了单斜结构,而且有更高的结晶度、表面氧空位密度和光生电荷载流子分离效率,更强的光吸收和更低的带隙能.在这些F掺杂BiVO4样品中,以np/nBi的理论值为1.0且带隙能为2.43 eV的F掺杂BiVO4样品的光催化活性最好(90 min内苯酚的降解率可达95％).这一优良的光催化性能与其具有最高的结晶度、表面氧空位密度和光生电荷载流子分离效率,最强的光吸收和最低的带隙能有关.%F-doped BiVO4 photocatalysts were fabricated by using a simple one-step alcohol-hydrothermal method with NH4F as the precursor of the dopant.The physicochemical properties of the photocatalysts were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),X-ray photoelectron spectroscopy (XPS),ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis),and photoluminescence spectra (PL).Their photocatalytic activities were determined through the degradation of phenol in the presence of a small amount of H2O2 under visible-light illumination.It is found that compared to the un-doped BiVO4 sample,the F-doped BiVO4 samples retained the monoclinic structure and had higher crystallinity,surface oxygen vacancy densities and separation efficiency of photogenerated charge carriers,stronger optical absorbance performances,and lower bandgap energies.Among these F-doped BiVO4 samples,the F-doped BiVO4 sample (nominal nF/nBi=1.0,bandgap energy=2.43 eV) exhibited the best photocatalytic performance (the conversion of phenol up to 95％ in 90 min),due to the highest crystallinity,surface oxygen vacancy density,and separation efficiency of photogenerated charge carriers,the strongest optical absorbance performance,and the lowest bandgap energy.