Synthesis of BiVO4via oxidant peroxo-method: insights into the photocatalytic performance and degradation mechanism of pollutantsElectronic supplementary information (ESI) available. See DOI: 10.1039/c5nj00984g

• Main Authors: Lopes, Osmando F, Carvalho, Kele T. G, Macedo, Gabriel K, de Mendonça, Vagner R, Avansi, Waldir, Ribeiro, Caue
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c5nj00984g

This paper reports the synthesis of monoclinic bismuth vanadate (BiVO 4 ) by the oxidant peroxide method with crystallization under hydrothermal conditions, and its catalytic performance on the photodegradation of pollutants under visible light. The as-synthesized BiVO 4 materials were characterized by means of X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, Ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and scanning electron microscopy (SEM). Hydrothermal treatment above 80 °C was required to obtain pure monoclinic BiVO 4 phase by releasing V 5+ ions from vanadium peroxo complexes. With the increase in hydrothermal reaction temperature, the particle size decreased. All BiVO 4 samples presented large size and shape distribution and band gap of approximately 2.40 eV. The as-prepared BiVO 4 catalysts showed high photoactivity for decomposition of model pollutants, methylene blue (MB) and rhodamine B (RhB) dyes, under exposure to visible light. The photodegradation mechanism was evaluated by adding scavengers, DMSO and KBrO 3 , which were used to probe &z.rad;OH radical and conduction band (CB) electrons, respectively. It was observed that photodegradation of MB and RhB dyes is caused by the action of &z.rad;OH radicals, and that BiVO 4 CB electrons do not have reduction potential sufficiently high to reduce dissolved oxygen to O 2 − &z.rad;. It was proven that the indirect mechanism, i.e. &z.rad;OH radical formation, plays the major role on the BiVO 4 -assisted photodegradation process. A new method was proposed to obtain monoclinic BiVO 4 with high photoactivity under visible light and its mechanism of photodegradation was investigated.