Abstract
•Ag-BiVO4 is synthesized by photo-deposition method.•Ag-BiVO4 is designed to match with ROS and dyes’ redox potentials (rational design).•Material has been tested under LED towards degradation of cationic and anionic dyes.•Catalyst degrades MB and BG by 91 % and 84 % within 20 min, respectively.•Catalyst degrades AR and MO by 79 % and 65 % within 60 and 120 min, respectively.
By employing a rational design approach of matching redox potentials of dye, catalysts, and reactive oxygen species (ROS), Ag-BiVO4 photo-catalysts of 2, 5 and 7 wt% Ag were successfully prepared via sol-gel and UV photo-reduction methods. The as-prepared composites over-perform existing counterparts by exhibiting excellent photocatalytic properties towards degradation of cationic methylene blue (MB, 20 min, 90.9 ± 2.4 %), brilliant green (BG, 20 min, 84.0 ± 2.7 %) and rhodamine B (RhB, 120 min, 90.5 ± 3.3 %) as well as anionic acid red 1 (AR, 60 min, 79.0 ± 2.5 %) and methyl orange (MO, 120 min, 64.9 ± 2.0 %) dyes. Furthermore, based on our novel approach of rational design, the degradation of MB dye was ascribed to photoelectrons from n-type BiVO4, while degradation of MO and AR was attributed to photo-holes from p-type Ag2O. Meanwhile, BG and RhB dyes degrade due to photoelectrons and photo-oxidation by ROS, which was confirmed by carrier scavenger experiments. Results indicate that Ag-BiVO4 oxide can be efficiently used for wastewater treatment, solar energy, water splitting, and medicine.