Three-dimensional dendritic C/PbWO4 composite photocatalyst with different C content (Mass fraction=0.13％,0.26％,0.52％,0.78％) was synthesized by a hydrothermal method.The photocatalysts were characterized by X-ray diffraction,N2 sorption measurements,scanning electron microscopy,transmission electron microscopy,energy dispersive X-ray spectroscopy,ultraviolet-visible diffuse reflectance spectroscopies,photoluminescence,and photoelectrochemical measurement.The results showed that the dendritic C/PbWO4 composite photocatalyst with 0.52％ C exhibits the best photocatalytic performance in degrading orange Ⅱ,methyl orange and rhodamine B.Under the light irradiation for 100 min,the degradation rate of the acid orange Ⅱ (20 mg· L-1) over 0.52％ C/PbWO4 reached 97％ which was about 2.48 times as that of bare PbWO4.The main reason for the increase of activity is that carbon attached to the surface of the catalyst becomes the electron trapping center,and it can effectively capture the photogenerated electrons.Therefore,the photo-generated electron-hole pairs were effectively separated to produce more active species (· OH,h+) to participate in the degradation of organic dye molecules.%采用水热法合成了一种高结晶度的3D树枝状C/PbWO4复合光催化剂(其中碳的质量分数分别为0.13％ 、0.26％、0.52％、0.78％).应用X射线衍射、N2物理吸附、扫描电子显微镜、透射电子显微镜、能量色散X射线光谱、紫外可见漫反射光谱、光致发光光谱和光电流响应等手段对合成样品进行了表征.研究结果表明,当C的复合量为0.52％时,催化剂在降解偶氮染料酸性橙Ⅱ、甲基橙和罗丹明B呈现出最高的光催化活性,在光照100 min内对20 mg· L-1酸性橙Ⅱ的降解率达到97％,为纯PbWO4的2.48倍.C/PbWO4复合光催化剂活性提高的主要原因是掺杂在催化剂表面的C成为了电子俘获中心,有效俘获光生电子,促进光生电子和空穴分离的显著效果,从而产生更多活性物种(·OH、h+)参与染料分子的降解,提升光催化活性.
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