Tailoring the structural and photocatalytic properties of Ag-doped SnO2 thin films: Influence of dopant concentration, stability, and reusability
Academic Article in Scopus
Pure and Ag-doped SnO2 thin films (0.02% and 7% Ag) were synthesized by nebulized spray pyrolysis (NSP) and deposited on glass substrates to evaluate their photocatalytic performance toward methylene blue degradation. A 0.1 M SnO2 precursor solution was prepared by dissolving SnCl4·5H2O in a 3:1 mixture of isopropyl alcohol (IPA) and distilled water, while AgNO3 was added in controlled proportions relative to tin chloride to obtain the corresponding doping levels. Film deposition was carried out at 200 °C for 60 min, using a tin bath to ensure uniform substrate heating and promote film homogeneity and adhesion. Comprehensive structural (XRD, FTIR), morphological (SEM), and optical (UV¿Vis, photocatalysis) analyses were performed. SEM and XRD revealed that the SnO2/Ag@7 film exhibited the smallest crystallite size (18¿20 nm), a highly porous morphology, and preferential orientation along the (200) plane. FTIR confirmed characteristic Sn¿O¿Sn stretching modes and surface modifications associated with Ag incorporation. UV¿Vis analysis showed notable band gap band gap modulation/widening due to Burstein¿Moss effect in the doped films, enhancing UV-light absorption. Photocatalytic tests demonstrated that the SnO2/Ag@7 film achieved up to 92% methylene blue degradation under UV-light irradiation, significantly outperforming pure SnO2. This enhancement is attributed to improved charge-carrier separation and the plasmonic activation of Ag nanoparticles. These results highlight that controlled Ag doping effectively tailors the structural orientation and electronic properties of SnO2 thin films, offering a promising strategy for advancing photocatalysts for environmental remediation.
