Preparation, characterization and photodegradation mechanism of 0D/2D Cu2O/BiOCl S-scheme heterojunction for efficient photodegradation of tetracycline

Single-phase photocatalysts exhibit low performance of photocatalytic degradation of pollutants, which is mainly due to the fact that most intrinsic photocatalysts can only produce one active species for degradation reactions. In order to solve this problem, the 0D/2D Cu2O/BiOCl S-scheme heterojunction was successfully constructed through a facile hydrothermal route. The obtained 0D/2D Cu2O/BiOCl displays high catalytic activity for tetracycline (TC) photodegradation, and 90.3% of TC was photodegraded within 80 min, which is much better than that by pure Cu2O and BiOCl. The excellent photocatalytic activity can be ascribed to the formation of S-scheme heterostructures, which enables the photocatalyst to generate superoxide radicals and hydroxyl radicals, and at the same time, makes the oxidation potential more positive and the reduction potential more negative. It is further proved by the results of experimental characterization and theoretical calculation show that the built-in electric field between Cu2O and BiOCl is a key factor in inducing the path of S-scheme electron transmission. In addition, the effects of various reaction conditions, including catalyst dosage, pH value and reaction temperature, on the photodegradation of tetracycline were discussed in detail. The intermediates and degradation path were also discussed in detail by liquid chromatography-mass spectrometry.