Studying the Effects of Cu Doping on Structure and Photoluminescence Properties of SnO₂Nanoparticle with Its Effectiveness towards the Mineralization of Toxic Industrial Dye

The structural and optical properties of tin oxide (SnO2) nanoparticles doped with Cu2+ ions have been investigated. Suppression of grain growth of tetragonal rutile structured SnO2 was observed with copper doping which generates more and more nucleation sites, resulting weak crystallinity in Cu-SnO2. Morphological analysis by FESEM showed the formation of nanoparticles with uniform size and shape for the pristine sample which altered significantly with copper doping. The optical absorption spectra of the samples show the compression of the band gap (BG) of SnO2 with Cu doping which is due to the creation of defect states linked with oxygen vacancies. The photoluminescence (PL) spectra of the doped samples possess enhanced visible emissions, which is mainly due to the oxygen vacant defects generated by the doping of copper impurity. The degradation efficiency of Cu-SnO2 was found to be higher (91.32%) in degrading Congo red dye as compared to pure SnO2 owing to a better change separation efficiency and prohibition of e - -h + recombination. The effect of photocatalyst loading, initial dye concentration, and pH on degradation efficiency was also studied in detail and the prepared nanocatalysts were found to be stable even after fourth cycle of degradation.