BiOI/Bi2O2[BO2(OH)] heterojunction with boosted photocatalytic degradation performance for diverse pollutants under visible light irradiation

Construction of heterojunction photocatalyst is a very useful approach to enhance photocatalytic activity. In particular, the coupling of narrow-band-gap semiconductor and wide-band-gap semiconductor can solve their inherent drawbacks, simultaneously optimizing the photoabsorption and redox capabilities. In this work, a series of BiOI/Bi2O2[BO2(OH)] heterojunction photocatalysts were synthesized by an in-situ precipitation method. The crystal structure, morphology and surface chemical composition were analyzed to confirm the heterojunction formation. BiOI/Bi2O2[BO2(OH)] heterojunctions show increased specific surface area, which can provide more absorptive and catalytic sites for pollutants. Particularly, the recombination of photogenerated electrons and holes in BiOI/Bi2O2[BO2(OH)] was severely inhibited. Compared to the pristine BiOI and Bi2O2[BO2(OH)], the BiOI/Bi2O2[BO2(OH)] heterojunctions demonstrated substantially enhanced visible-light driven photocatalytic activity for degradation of various contaminants, including methyl orange, methylene blue and tetracycline hydrochloride. The superoxide radicals (O-center dot(2)-) and holes (h(+)) were determined as the main active species and played crucial role in the photodegradation process, which also verified the formation of type II heterojunction between BiOI and Bi2O2[BO2(OH)]. This work provides an efficient heterojunction photocatalyst for environmental remediation.