Study on the synergistic effect of terbium-doped SnO2 thin film photocatalysts for dye degradation

The undoped and terbium (Tb)-doped SnO2 thin films are coated on the glass substrates using the nebulized spray pyrolysis (NSP) technique. The crystallite size is calculated using the Williamson-Hall method and is found to be decreased from 80 to 56 nm with the increase of Tb doping concentration. Atomic force microscope (AFM) images show the spheroidal shape of the grains. The elemental analysis of the samples was investigated by energy dispersive analysis of X-rays (EDX). An increase in absorbance and decrease in bandgap values provide more photon absorption which enhances the photocatalytic reaction. The PL studies reveal the creation of more defect levels by doping which provides more active sites for catalyzed reactions. The Tb doping with SnO2 improved the rate constant about 0.015/min, and a maximum photocatalytic dye degradation efficiency of 85% against methylene blue dye was observed. Therefore, the fabricated films found potential applications for photocatalysis that enable them to chemical industries.