Improving Photocatalytic Performance through Incorporation of Various Cations in A-site of Double Perovskite Material (Cs0.50MA0.50)2SnI6 for Degradation of Methylene Blue Dye Pollutant under Visible Light Irradiation

In this article, undoped double perovskite materials like caesium tin iodide (Cs2SnI6), methyl ammonium tin iodide [MA2SnI6: MA denotes CH3NH3+] and mixed double perovskite material [(Cs0.50MA0.50)2SnI6] were synthesized using a wet chemical methodology. The crystal structure confirmation, optical properties, thermal properties, surface morphology and presence of elemental composition of the prepared samples using XRD, UV, TGA and FESEM-EDAX analyses were thoroughly investigated. The synthesized materials were employed as photocatalysts to degrade methylene blue dye within 120 min under visible light. An increase in the optical properties of the synthesized double perovskite materials was confirmed by ultraviolet (UV) analysis, which showed that the introduction of various cations into the perovskite material at the A-site shifted the photoluminescence (PL) emission peak to the red. TGA results demonstrated that (Cs0.50MA0.50)2SnI6 has greater thermal stability, which was confirmed by the presence of 43% of sample despite the temperature reaching almost 870 ºC. Doped double perovskite material (Cs0.50MA0.50)2SnI6 exhibited increased photocatalytic activity, with methylene blue dye degradation efficiency attaining 89% after 120 min of visible light irradiation, which is greater than pure double perovskite materials. The photocatalytic degradation of methylene blue dye is mostly facilitated by hydroxyl radicals and holes, according to a radical trapping experiment that we conducted by employing different scavengers. The results of the current work showed that doped double perovskite materials [(Cs0.50MA0.50)2SnI6] exhibit high thermal stability as well as higher photocatalytic activity than pure double perovskite materials. A possible photocatalytic reaction process is also diagrammatically using the band positions of double perovskite materials found using Mott-Schottky plots , which confirms that the synthesized double perovskite material has an N-type semiconductor nature.