| The development of new photocatalysts is necessary to substitute TiO2 whose conversion rate is limited in photocatalytic oxidation under visible light. The aim of this work is to synthesize monoclinic scheelite BiVO4 using mild and green method to improve the photocatalytic activity. The conduction band (CB) position of BiVO4 is a little higher than 0 eV indicating the excited electron was difficult to capture the O2 in air to generate·O2-. In order to enhance the transfer rate of electron the CuO-BiVO4 heterojunction is synthesized. The properties of the BiVO4 and CuO-BiVO4@C were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electronmicroscopy (HRTEM), Fourier transform infrared spectrometers (FTIR), photoluminescence (PL) spectra and UV-vis diffuse reflectance spectroscopy (UV-vis DRS). Besides, the photocatalytic oxidation activity of CuO-BiVO4@C was evaluated for degradation of toluene in gas phase and MB in aqueous solution under visible light irradiation. The carbon spheres are taken as supporting and sensitized the BiV04. The narrowed band gap BiVO4 (s-m) can be synthesized in hydrothermal methods a low temperature (190℃) without template for extended time (12h). Of all the modified BiVO4 samples, the order of photocatalytic activity is:CuO-BiVO4>Nb2O5-BiVO4> Fe2O3-BiVO4. CuO-BiVO4 heterojection improve the transfer rate of electron, CuO-BiVO4@C shows great photocalytic activity. Carbon sphere as an important functional material narrows the band gap to widen the light adsorbtion range, adsorbs the pollutants and makes the catalysts separated from the solution easier.
|
PDF Full Text Request