Photocatalytic degradation of azo dyes by BiOX (X = Cl, Br)

This work presents the preparation and photocatalytic activity of BiOX (X = Cl, Br), it is feasible to prepare BiOX by the hydrolysis of BiX3 (X = Cl, Br). Both BiOCl and BiOBr show photocatalytic activity for the photodegradation of azo dyes (methyl orange and congo red) under the simulated sunlight. We have measured the HO generated in the above process by terephthalic acid indirectly. Both BiOCl and BiOBr have been characterized by XPS, DRS, SEM, TEM, XRD and ξ potential. XPS data indicate that the surfaces of the BiOX samples are covered by low amounts of adsorbed azo dye molecules or/and intermediates produced during the dye photodecomposition.

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► It is very easy to prepare pure BiOX quickly and directly from BiX3 by the hydrolysis.
► BiOCl and BiOBr show photocatalytic activity.
► HO can be generated in the process of photocatalytic degradation of azo dyes by BiOX.