Bi2S3 nanorods and BiOI nanosheets co-modified BiOIO3 nanosheets: An efficient vis-light response photocatalysts for RhB degradation

Abstract

BiOIO3/BiOI/Bi2S3 (BBS-x) heterostructure composites are first synthesized via in situ reduction and chemical deposition. The BiOIO3/BiOI/Bi2S3 composites integrate the merits of BiOI and Bi2S3, with a widened light response range and improved light absorbance ability, as confirmed by the DRS test. The close type-Ⅱ interface along with carrier migrate and transfer mechanism can spatially isolate photoinduced e- and h+, hinder the recombination of photogenerated carriers and boost their efficiency transfer and separation, as proven by scanning electron microscopy, transmission electron microscopy, electrochemical impedance spectroscopy, transient photocurrent response, and photoluminescence. These properties enhance the photocatalytic activity of BiOIO3/BiOI/Bi2S3 composites when applied to the photodegradation of rhodamine B, regardless of their irradiation with simulated solar light or LED light. The BBS-0.75 composite has the highest apparent rate constant k (0.034 min−1) under simulated solar light irradiation, which is approximately 4.5 times greater than that of pure BiOIO3 (0.0076 min−1). The BBS-0.75 composite almost completely photodegrades RhB within 30 min under LED light irradiation. Free radical scavenging experiments reveal that •O2- and h+ are the main reactive species. Thus, a logical type-II carrier transfer mechanism with dye sensitization is proposed.