BiOBr0.75I0.25/BiOIO3 as a Novel Heterojunctional Photocatalyst with Superior Visible-Light-Driven Photocatalytic Activity in Removing Diverse Industrial Pollutants

A series of novel heterojunctional photocatalysts BiOBr0.75I0.25/BiOIO3 were synthesized by a facile deposition–precipitation method for the first time. In contrast to pristine BiOIO3, the photoabsorption of BiOBr0.75I0.25/BiOIO3 composites in visible light region is greatly promoted. All the BiOBr0.75I0.25/BiOIO3 composite photocatalysts exhibit highly enhanced photocatalytic activity in decomposing bisphenol A under visible light (λ > 420 nm) illumination, and the 20% BiOIO3-BiOBr0.75I0.25 sample possesses the optimal photoreactivity, which is 7.4, and 3.3 times higher than those of pure BiOIO3 and BiOBr0.75I0.25. Moreover, the 20% BiOIO3-BiOBr0.75I0.25 sample displays superior photocatalytic performance against diverse industrial contaminants and pharmaceuticals, including methyl orange, phenol, 2,4-dichlorophenol, chlortetracycline hydrochloride, and tetracycline hydrochloride. The enhancement of phototcatalytic activity is ascribed to the profoundly promoted transfer and separation of photoexcited charge carriers, which is verified by transient photocurrent response and photoluminescence emission. In addition, the photocatalytic mechanism over composite photocatalyst under visible light irradiation is systematically investigated by active species trapping experiment and •OH quantification experiment. This work may provide a new hint for fabrication of high-performance heterojunctions by combining the narrow-band gap and wide-band gap semiconductors.