Rational composition tuning of NH₂-UiO-66(Ce)/g-C₃N₄/MoS₂ ternary photocatalysts for enhanced visible-light degradation of tetracycline in water

Pharmaceutical contaminants such as tetracycline persist in aquatic environments because of their chemical stability and resistance to conventional wastewater treatment, creating a need for more effective visible-light-responsive photocatalysts. This study systematically investigated the composition-dependent photocatalytic performance of NH₂-UiO-66(Ce)/g-C₃N₄/MoS₂ ternary composites using a statistically designed mixture approach. A series of photocatalysts with varying component ratios was synthesized through sonication-assisted assembly and evaluated for tetracycline degradation under visible-light irradiation. FTIR, SEM, and EDX analyses confirmed successful composite formation, homogeneous elemental distribution, and favorable interfacial contact among the constituent materials. Mixture-design analysis demonstrated that degradation efficiency was primarily governed by linear compositional effects, whereas the apparent pseudo-first-order kinetic constant was strongly influenced by synergistic interactions, particularly between g-C₃N₄ and MoS₂. Numerical optimization identified an optimum composition containing 27.64 wt% g-C₃N₄ and 72.36 wt% MoS₂, achieving an experimental degradation efficiency of 67.95% after 120 min with an apparent pseudo-first-order kinetic constant of 0.0096 min⁻¹. Post-reaction characterization indicated that the composite retained its overall structural integrity, with activity loss primarily associated with surface fouling and partial blockage of active sites rather than structural collapse. Although the photocatalytic activity is moderate relative to some recently reported systems, this work establishes quantitative composition-performance relationships and provides statistically validated design guidelines for rational optimization of NH₂-UiO-66(Ce)/g-C₃N₄/MoS₂ photocatalysts for antibiotic degradation under visible-light irradiation. • NH₂-UiO-66(Ce)/g-C₃N₄/MoS₂ ternary photocatalysts were successfully synthesized. • Mixture design identified composition-dependent photocatalytic performance. • Optimized composition achieved 67.95% tetracycline degradation under visible light. • Statistical modeling revealed strong synergistic interaction between g-C₃N₄ and MoS₂.