One-step synthesis of Z-scheme BiOBr/Bi/BiOI efficient heterojunction photocatalysts and the effect of ascorbic acid

Ternary-component BiOBr/Bi/BiOI composites were successfully prepared by a one-step hydrothermal method under the reducing effect of ascorbic acid. Ascorbic acid not only converts Bi 3+ to Bi 0 as a reducing agent, but also inhibits the growth of grains and controls the morphology, resulting in a multilayered hierarchical floral structure of the BiOBr/Bi/BiOI composites formed by the assembly of nanosheets dotted with nanoparticles on the surface. The composite has highest photocurrent density, lowest photogenerated electron-hole recombination rate and high specific surface area, and exhibits excellent degradation performance for both single and mixed pollutant systems of tetracycline, rhodamine B and methylene blue. h + is the most dominant reactive oxygen species in the photodegradation process, while ·OH and ·O 2 − provide weak auxiliary degradation. A Z-scheme photocatalytic degradation mechanism of BiOBr/Bi/BiOI with excellent photocatalytic performance was proposed.