Characterization of BiOCl/BiOI binary catalyst and its photocatalytic activity towards rifampin

BiOI and BiOCl nanoparticles (NPs) were coupled to prepare the BiOI-BiOCl binary catalyst. The DRS, XRD, FT -IR, SEM-EDS, BET, HRTEM, and TG techniques were applied in the samples' characterization. The crystals with sizes of 25, 33, and 25 nm (by the Scherrer formula) and 26, 23, and 27 nm (by the Williamson-Hall formula) were estimated for BiOCl, BiOI, and BiOCl-BiOI, respectively. The binary catalyst BET surface area: 7.33 m(2)/g, pore volume: 0.0952 cm(3), and particle diameter of 52 nm were also obtained. The interlayer distance for the (101) lattice plane of BiOCl is about 0.338 nm and for the (012) plane of BiOI is about 0.301 nm from HRTEM images. The band gaps of 3.40, 1.87, and 1.84 eV were estimated for BiOCl, BiOI, and their coupled sample, while their pHpzc values were 7, 7.9, and 9.5, respectively. The enhanced photocatalytic activity was achieved towards rifampin under visible light irradiation for the binary catalyst. This boosted photocatalytic activity depended on the moles of the ingredient and a 1:1 value showed the highest efficiency. The increase in the source power from 60 to 300 W increased the photodegradation rate constant from 0.040 min-1 to 0.056 min(-1) (t(1/2 )of 17.3 and 12.4 min). The highest rate constant of 0.069 min(-1) (t(1/2) = 10.0 min) was obtained when sunlight was used.