Enhanced Photocatalytic Properties of Restacked Unilamellar [SrTa 2 O 7 ] 2- Nanosheets of Aurivillius Phase Layered Perovskites.

In the present work, unilamellar [SrTa 2 O 7 ] 2- perovskite nanosheets with variable lateral dimensions were synthesized via a high-yield, three-step liquid exfoliation route from layered Bi 2 SrTa 2 O 9 . The photocatalytic activity of the parent and exfoliated layered perovskites was evaluated for the photocatalytic dye degradation of Rhodamine B under UV light (254 nm) and reduction of water to H 2 under the full solar spectrum. A comparative study of the photocatalytic behavior of unilamellar [SrTa 2 O 7 ] 2- perovskite nanosheets and parent layered structure showed a significant improvement in both hydrogen evolution (98.20 vs 3 μmol g -1 ) and Rhodamine B degradation time (180 vs 30 min), with the restacked nanosheets. The exfoliation of layered perovskites not only increases their specific surface area, providing more active sites, but also reduces the recombination probability of electrons and holes due to their unilamellar structure and reduced charge transport pathways. The synthesis and preparation of strong acid solids such as [SrTa 2 O 7 ] 2- perovskite nanosheets can be a promising approach for effective adsorption of pollutants with cationic nature and more efficient electron transfer between the dye and catalyst. Finally, the photocatalytic characteristics of the restacked unilamellar [SrTa 2 O 7 ] 2- nanosheets remained unchanged after three successive cycles of recycling-reusing.