Preparation And Photocatalytic Property Of Novel Visible-Light-Driven Bismuth Vanadate Photocatalysts

Recently, the global environment pollution and energy crisis become more and more serious. The research and development of semiconductor photocatalysis with high utilization efficiency of solar energy to split water into hydrogen or degrade organic pollutant has become an available approach to settle the environment and energy issues. Photocatalysis is an advanced technology that employing inorganic semiconductors as photocatalysts, and using the photogenerated electrons and holes in photons excitated semiconductor, pollutants can be degraded by oxidization or reduction. After photocatalytic process, organic pollutants are decomposed into water, carbon dioxide and non-toxic inorganic acid. So we devote ourselves to design and development of new and efficient BiVVO4photocatalyst with visible-response and different morphologies by hydrothermal route. A series of BiVO4samples are synthesized and characterized. We systemally analyzed their formation mechanisms, studied the relationship between prepared conductions and the crystal phase and morphology of samples, investigate the photocatalytic activity under the mimetic visible-light irradiation by using RhB as target degradation, and discussed the degradation mechanism. The main research contents and results are given as follows:(1) Successfully synthesized the dumbbell-like BiVO4photocatalyst via a hydrothermal route. The crystal structures, morphologies, chemical composition and visible-light absorption of the obtained products were well-characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and diffuse reflectance spectroscopy (DRS). The different period morphologies of the dumbbell-like BiVO4samples were obtained by controlling the hydrothermal time, the results indicated that the nucleation and growth of the dumbbell-like samples were dominated by a'nucleation-dissolution-recrystallization' growth mechanism. Moreover, BiVO4samples with various morphologies were fabricated by controlling the reaction concentration, the PH value and the kind of and the dose of surfactants. Rhodamine B (RhB) was selected as a target pollutant to evaluate the photocatalytic efficiency of BiVO4catalysts under different conditions, it is shown that the dumbbell-like BiVO4photocatalyst exhibit an excellent photocatalytic activity that better than TiO2(P25) in the photodegradation of RhB under visible light irradiation.(2) BiVO4core-in-hollow-shell spheres were synthesized by using a mild addictive-free hydrothermal treatment. The crystal structures, morphologies, chemical composition, visible-light absorption and specific surface area of the obtained products were well-characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS) and Brunauer-Emmett-Teller (BET). The ultrahigh BET specific surface area of ca.13.092m2/g is displayed for the BiVO4core-in-hollow-shell spheres. We observed the growth process of the prepared BiVO4samples by controlling the hydrothermal time, and the results proved that the nucleation and growth of the BiVO4core-in-hollow-shell spheres were based on 'Ostwald Ripening'mechanism. Rhodamine B (RhB) was selected as a target pollutant to evaluate the photocatalytic efficiency of different morphologies BiVO4catalysts, it is shown that the BiVO4core-in-hollow-shell spheres with thinner shell exhibit excellent photocatalytic activity in the photodegradation of RhB under visible light irradiation.