Visible-Light-Driven AO7 Photocatalytic Degradation and Toxicity Removal at Bi-Doped SrTiO3

Abstract

In this study, Bi-doped SrTiO3 perovskites (Sr1−xBixTiO3, x = 0, 0.03, 0.05, 0.07 and 0.1) were synthesized using the solid-state method, characterized, and tested as photocatalysts in the degradation of the azo dye acid orange 7 (AO7) under visible light. The perovskites were successfully synthesized, and XRD data showed a predominant, well-crystallized phase, belonging to the cubic perovskite symmetry. For the doped samples, a minority phase, identified as bismuth titanate, was detected. All doped samples exhibited improved photocatalytic activity under visible light, on the degradation of AO7 (10 mg L−1), when compared with the undoped SrTiO3, with an increase in relative Abs484 nm decay from 3.7% to ≥67.8% after 1 h, for a powder suspension of 0.2 g L−1. The best photocatalytic activity was exhibited by the Sr0.95Bi0.05TiO3 perovskite. Reusability studies showed no significant loss in photocatalytic activity under visible light. The final solutions showed no toxicity towards D. magna, proving the efficiency of Sr0.95Bi0.05TiO3 as a visible-light-driven photocatalyst to degrade both the AO7 dye as well as its toxic by-products. A degradation mechanism is proposed.

Ag/Cr-TiO2 and Pd/Cr-TiO2 for Organic Dyes Elimination and Treatment of Polluted River Water in Presence of Visible Light

“…Indeed, a proper photocatalyst dosage may improve the photocatalytic performance minimizing the energy cost for the treatment. Indeed, it is a crucial parameter of photocatalytic processes since the number of active sites and photo-adsorption capacity of the catalyst utilized have a significant impact on the photodegradation efficiency [ 42 ]. For this reason, the effect of Pd(0.25%)/Cr-TiO 2 dosage on AO7 photocatalytic degradation was investigated, and the optimal loading value was determined.…”

The Emerging Career of Strontium Titanates in Photocatalytic Applications: A Review

“…The highest degradation efficiency was obtained for ciprofloxacin. In a recent study, Bi-doped SrTiO 3 was synthesized using a solid-state method for the removal of acid orange 7 dye under visible light [81]. The doped samples showed a higher performance for the degradation of the dye than the undoped with the optimal amount of doping, in the case of sample Sr 0 .…”

Nanocubic Copper-Doped SrTiO3 for Photoreduction of Cr(VI) and Photodegradation of Methyl Violet

“…Despite the fact that it has high chemical and thermal stability, the high band gap of SrTiO 3 limits its catalytic applications in the visible region. Hence, several modification routes to enhance the photoactivity like doping, defect engineering, or compositing with other semiconductors or layered carbon-based materials are employed to shift the band gap of the catalyst to the visible region. − Although doping is more conducive and an easy approach, the formation of mid-gap states due to doping increases the rate of recombination opposing the advantageous effect of the reduced band gap, making this route less effective. Hence, an efficient synthetic approach like the solvothermal method is needed that produces perovskites without midgap states .…”