High surface area Gd/Mn co‑doped LaFeO₃ CNT photocatalyst with superior solar amoxicillin degradation and recyclability across wide pH range

An advanced photocatalyst that is designed to eliminate antibiotics from effluent was developed by employing a dual-route synthesis strategy. To guarantee uniform nanocrystallinity, compositional homogeneity, and controlled morphology, a microemulsion approach was employed to synthesize LaFeO₃ perovskite co-doped with Gd and Mn (La_1-xGd_xFe₁₋_yMn_yO₃). The co-doped perovskite was subsequently improved with carbon nanotube (CNT) through ultrasonication method. This network enables the efficient transport of charge carriers and prevents e⁻/h⁺ recombination. The nanocomposite that resulted exhibited a reduced optical bandgap of 2.04 eV (GM-LFO), exceptional electrical conductivity measured at 4.37 × 10³ S m⁻¹, and a high surface area of 114.3 m²g⁻¹. The synergistic modifications led to exceptional photocatalytic performance, achieving 98.86% degradation of amoxicillin in just 60 min under solar irradiation. This achievement was accompanied by a pseudo-first-order rate constant of 0.032 min⁻¹. The material maintained 90.79% activity after five cycles and exhibited over 96% degradation efficiency across a pH range of 1 to 13 (with an isoelectric point of approximately 5.3). Additionally, it demonstrated strong reusability. Radical scavenging experiments demonstrated that hydroxyl radicals are the primary oxidative species, with the involvement of superoxide radicals. This finding is consistent with the documented charge-transfer mechanisms of LaFeO₃/CNT heterojunctions. In contrast to the most prominent perovskite-based photocatalysts, the microemulsion–ultrasonication assembly of rare-earth/transition-metal co-doping in conjunction with CNT integration exhibits improved adaptability, stability, and activity across a range of pH degrees. This investigation introduces a synthesis method for the development of perovskite based multifunctional photocatalyst with large surface area, improved charge transfer ability, lower bandgap energy. The rapid and comprehensive removal of pharmaceutical contaminants from water is made possible by the synergistically engineered band structures, surface areas, and charge dynamics of these materials.