Advancing perovskite photocatalysis: synergistic effect of Nd/Mn co-doping and CNTs integration for water treatment

Advanced water purification with excellent efficiency has been a significant challenge for humanity, and LaFeO₃-based perovskite semiconductors have been the subject of extensive research in recent years as promising candidates for efficient photocatalysts due to their stable structure and modifiable optoelectronic properties. However, the photocatalytic efficiency of LaFeO₃ perovskites is limited by rapid charge recombination, poor charge transport, and limited visible-light harvesting, all of which can impede the generation of active species. In this study, A/B-site Nd/Mn co-doping, nanostructure modulation, and CNTs integration were effectively merged as a multi-level engineering method to improve the optical response, electronic conductivity, and active surface area of LaFeO₃. The optimized 3% co-doping and 15% CNT contents enabled the final synthesized composite to exhibit excellent light harvesting due to a lower band gap, higher surface area, higher transient photocurrent, lower PL emission intensity, and good electrical conductivity. All these integrated features enabled the Nd/Mn-doped LaFeO₃ perovskite-CNTs nanocomposite to show 95% degradation of Brilliant Blue dye (BBD, 15 mg L^-1) in 1.5 h with a pseudo-first-order rate constant of 0.032 min^-1-triple that of pristine LaFeO₃. Mechanism study showed that superoxide radicals (˙O₂ ^-), which were formed via both conduction-band electron transfer and CNT-induced charge transfer, were the major reactive species for BBD degradation. Structural stability and the composite's reusability (up to six cycles with ∼97% activity after the conclusion of six cycles) indicate the suitability of the presented composite as a successful catalyst material.