A visible light driven 3D hierarchical CoTiO3/BiOBr direct Z-scheme heterostructure with enhanced photocatalytic degradation performance

Abstract

A series of novel three-dimensional (3D) CoTiO₃/BiOBr (CTBB) hierarchical heterostructures were prepared via a simple hydrothermal method. In comparison with pure CoTiO₃ and BiOBr, all the CTBB nanocomposites display enhanced photocatalytic performance toward dye decomposition. Particularly, CTBB-5 reveals the best photocatalytic efficiency for RhB removal with a K of 0.2030 min⁻¹, which is about 50.75 and 3.02-fold higher than that of pure CoTiO₃ and BiOBr, respectively. The outstanding activity is further demonstrated by MO photodegradation. The dramatically enhanced activity can be attributed to the increased surface area and reduced recombination probability of charge carriers. Furthermore, CTBB-5 exhibits excellent stability after repetitively running four times. The h⁺ and ˙O₂⁻ are identified as the dominating reactive species contributing to the oxidation reaction. Finally, a possible Z-scheme charge transfer mechanism is presented and analyzed in detail.