Enhanced photocatalytic performance of BiOBr nanoplate with porphyrin complex

Wastewaters generated from the textile industry contain large amounts of azo-dyes. Azo dyes are synthetic colored organic compounds. They are manufactured and used widely [1]. In order to solve such problems, degradation of aqueous organic pollutants in wastewater through semiconductor photocatalysis has received significant attention over the last decades. Among the various narrow band gap semiconductors, bismuth oxyhalides, BiOX (X= Cl, Br, I) have been also found to act under visible light irradiation [2], Furthermore, BiOX are nontoxic and the environment compatible photocatalysts with low cost [3]. Therefore, BiOX has attracted increasing attention in practical industrial applications, especially in the degradation of organic pollutants [3] and in the fabrication of photoelectrochemical cells [4]. BiOBr, as one of Bi based semiconductor materials, has attracted the attention of researchers due to its unique lamellar crystal structure, efficient visible light absorption and charge transfer ability [5]. BiOBr nanoplates were synthesized through the co-precipitation method. In a typical experiment to prepare the BiOBr sample, Bi(NO3)3.5H2O powder was firstly dissolved in HNO3 (solution A). Solution B contained KBr and CH3COONa in distilled water. Solution A was added rapidly to the solution B under vigorous stirring. Subsequently, the mixtures were vigorously stirred for 12 h. After the reaction was completed, the resulting product was collected by centrifugation, washed several times with distilled water. The resulting nanoplates have a tetragonal phase. To improve the visible light performance of the prepared BiOBr in the photocatalytic reactions, the prepared photocatalyst were functionalized with tin complex of porphyrin photosensitizer (Sn-TCPP). To photosensitize the prepared BiOBr by the Sn-TCPP, BiOBr and the porphyrin complex with weight ratio of 10 to 1 were refluxed in DMF solvent. After washing with DMF, the synthesized product was obtained and named BiOBr/SnTCPP. The prepared photocatalysts were characterized through FT-IR, DRS, XRD and SEM analysis. The photoactivity activity of the synthesized sample was investigated via photodegradation of a colored pollutant of methyl orange (MO) and 2, 4-dicloro phenol. The results showed that BiOBr photosensitized with SnTCPP is able to destroy 78% of MO and 80% of 2, 4-dicloro phenol in 240 min under visible light radiation.