Rational design of TiO₂/MnMoO₄/MoO₃ nanocomposites: Visible-light-promoted photocatalysts for decomposition of tetracycline with tandem n-n heterojunctions

In this research, MnMoO₄ and MoO₃ nanoparticles were simultaneously integrated with TiO₂ particles by reflux method preceded by calcination step. The synthesized nanocomposites containing tandem n-n heterojunctions showed superior efficiency in photodegradation of tetracycline (TC) antibiotic and three toxic dyes including rhodamine B (RhB), methylene blue (MB), and malachite green (MG). The degradation rate constant of TC, MB, MG, and RhB over the optimum photocatalyst was 50.4, 32.2, 42.2, and 34.5 times more than pristine TiO₂, respectively. The superior activity of the ternary photocatalyst was assigned to more generation of charges and efficacious separation and migration of electron/hole pairs, which were corroborated by UV–vis DRS, PL, EIS, and photocurrent density analyses. This study revealed that the novel ternary TiO₂/MnMoO₄/MoO₃ photocatalysts are very promising materials for photodegrading industrial effluents in the environment.