Improved photocatalytic activity under the sunlight of high transparent hydrophilic Bi-doped TiO2 thin-films

The Doping of TiO2 with various elements increases its photo-catalytic activity due to the formation of new energy levels near the conduction band. In this work, titania (TiO2) and bismuth-doped titania (Bi-doped TiO2) films were made by the sol-gel process with dip coating method employed for more cost-effective approach. The study investigated Bi-doped TiO2 films on glass substrates at different Bi concentrations (0.1, 1, 3, 5, and 7 wt%) to use as solar-photocatalysts for degradation of Rhodamine-B in the presence of Ag+, H2O2, and C3H8O3 as hole-scavengers. The film fabricated at 7 wt% Bi showed high photocatalytic activity with the addition of Ag+ as hole-scavenger, achieving 79.84%. When increasing doping Bi (from 0.1 to 7 wt%), the transmittance properties increased (from 66.27 to 97.46 %) and affected the morphology of the films structure. All films display hydrophilic characteristics with contact angles between 30 degrees to 70 degrees. The film of 7 wt% Bi-doped TiO2 achieved a good photocatalytic efficiency (compared to other films) at similar to 34,65% corresponding to (1 0 1) anatase phase, 15.2 nm of crystal size, 312.5 nm of film-thickness, and 3.65 eV of bandgap energy. In the film containing 7 wt% of Bi-doped TiO2, the photocatalytic degradation of rhodamine-B was improved by approximately 14.49, 33.56, and 45.19% with the addition of C3H8O3, H2O2, and Ag+, respectively. Therefore, this work eases the fabrication of Bi-doped TiO2 thin films with high photo-catalytic activity, suggesting potential applicability in environmental applications to treat wastewater from metal ions (Ag+) and dye Rhodamine-B.