Photodegradation of methyl orange by BiOI‐sensitized TiO ₂

Abstract

Abstract BiOI‐sensitized titanium dioxide (TiO 2 ) photocatalysts were prepared by a deposition method at room temperature and characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, and Brunauer‐Emmett‐Teller surface area measurements. The photocatalytic activities of the catalysts were evaluated for the degradation of methyl orange (MO) solution under UV and visible light irradiation. The effects of catalyst amount, initial pH value, initial concentration of MO, as well as KI amount were investigated. The repeatability of photocatalytic activity of the 1.7% BiOI/TiO 2 catalyst was also tested. It is shown that BiOI sensitization enhances the photocatalytic activities of TiO 2 . With BiOI content increasing, the photocatalytic activities of BiOI/TiO 2 under UV and visible light irradiation first increase, reaching a maximum around BiOI content of 1.7%, and then decrease with further increasing BiOI content. The 1.7% BiOI/TiO 2 catalyst obviously exhibits much higher visible light photocatalytic activity than P25, and its UV light photocatalytic activity is slightly higher than that of P25. Under the conditions of a catalytic dose of 1.5 g·L −1 , initial pH of 3.0, initial MO concentration of 20 mg·L −1 , UV power of 300 W, and air flow rate of 0.8 L·min −1 , complete degradatio is achieved within 60 min. The repeatability of photocatalytic activity of the 1.7% BiOI/TiO 2 catalyst is highly reliable.