Bi quantum dots on rutile TiO2 as hole trapping centers for efficient photocatalytic bromate reduction under visible light illumination

•Bi quantum dots deposited onto rutile TiO2 nanoparticles.•Hole trapping and consumption capability of Bi quantum dots.•Enhancement of the charge carrier separation in rutile TiO2.•Elimination of the need of sacrificial agents in photocatalytic reduction process.•Efficient photocatalytic bromate reduction under visible light illumination.