MoS₂/Cu/TiO₂ nanoparticles: synthesis, characterization and effect on photocatalytic decomposition of methylene blue in water under visible light

Photodegradation processes are of great interest in a range of applications, one of which is the photodecomposition of pollutants. For this reason, analysing nanoparticles that improve the efficiency of these processes under solar radiation are very necessary. Thus, in this study, TiO₂ was doped with Mo and Cu using low-temperature hydrolysis as the method of synthesis. Pure TiO₂ and x%MoS₂/Cu/TiO₂ nanoparticles were prepared, where x is the theoretical quantity of MoS₂ added (0.0%, 1.0%, 5.5%, 10.0%), setting the nominal quantity of Cu at 0.5 wt.%. The samples obtained were characterized by X-ray diffraction, Raman spectroscopy, X-ray electron spectroscopy and UV-Vis spectroscopy in diffuse reflectance mode. The results suggest that the TiO₂ structure was doped with the Mo⁶⁺ and Cu²⁺ ions in the position of the Ti⁴⁺. The x%MoS₂/Cu/TiO₂ samples presented lower band gap energy values and greater optical absorption in the visible region than the pure TiO₂ sample. Lastly, the photocatalytic activity of the samples was assessed by means of the photodegradation of methylene blue under visible light. The results show that when the quantity of Mo in the co-doped samples increased (x%MoS₂/Cu/TiO₂) there were significant increases of up to 93% in the photocatalytic activity.