A fair comparison between bismuth catalysts for application in photodegradation under visible and solar light

Abstract

Three different bismuth catalysts (Bi2WO6, BiOI and BiVO4) were synthesized using solvo- and hydrothermal methods. Different reaction times, calcination and the addition of poly (vinyl pyrrolidone) during synthesis were tested to investigate the effect of these variables on the catalysts’ morphology and photocatalytic activity. The photocatalytic activity was evaluated using the degradation of rhodamine B dye under both visible light and natural solar radiation. The Bi2WO6 samples presented good crystallinity and morphological similarities, despite having undergone different treatments. The BiOI and Bi2WO6 catalysts presented a spherical shape, and no morphological difference was observed as a result of the addition of PVP. The BiVO4 sample presented a parallelepiped shape. BiOI containing PVP and ethylene glycol was the catalyst that presented the highest activity, while BiVO4 presented the lowest. In experiments using scavengers, photogenerated holes demonstrated a key role in dye degradation.