LaVO4可见光催化降解罗丹明B的研究

Photocatalytic degradation of rhodamine B over LaVO4 under visible light irradiation

用溶胶-凝胶法在不同温度下煅烧，合成了系列LaVO4光催化剂，用XRD，FT-IR，SEM，BET，UV-Vis DRS对催化剂进行了表征，考察了其可见光催化降解罗丹明B的性质。结果表明，在200℃煅烧可合成t-LaVO4晶体，300℃以上煅烧有利于制备m-LaVO4。催化剂样品为多孔结构，比表面积大，可见光催化活性良好。300℃制备的样品具有最好的光催化活性，可见光催化6h后，罗丹明B降解率达65.45%，比TiO2的降解率高48.07%。加入电子受体或调节初始溶液pH值为酸性（pH=3）都可大幅度提高m-LaVO4的可见光催化活性，m-LaVO4可见光催化反应2h后，罗丹明B均可完全降解。

Lanthanide orthovanadate （LaVO4） photocatalysts were synthesized by sol-gel method under different calcined temperatures. The crystal structures, morphologies and photophysical properties of as-prepared photocatalysts were characterized by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM）, the Brunauer-Enmet-Teller （BET） method and UV-Vis diffuse reflectance spectra （UV-Vis DRS）. Meanwhile, their photocatalytic properties were investigated by the degradation of rhodamine B under visible light irradiation. The results indicated that t-LaVO4 crystal could be obtained by calcining amorphous complex gel at 200℃, and m-LaVO4 crystal prefered relatively high temperature of above 300℃. The porous photocatalysts possessed high BET surface areas and exhibited good photocatalytic properties under visible light irradiation. It was found that the m-LaVO4 crystal calcined at 300℃ showed the highest photocatalytic activity. The degradation of rhodamine B in the presence of m-LaVO4 crystal calcined at 300℃ reached to 65.45 % after 6 hours, which was 48.07 % higher in the comparison of conventional photocatalyst TiO2. Both adding electron acceptor and adjusting the pH value of initial solution to acid （pH=3） could enhance photocatalytic ability of m-LaVO4 remarkably. Rhodamine B could be degraded completely under visible light irradiation after 2 hours in such cases.