Unraveling the Photocatalytic Performance of La<sub>2</sub>O<sub>3</sub> Nanoparticles for the Degradation of Six Organic Dyes
S. V. Rahul, Amal George, Marcin R. Strąkowski, A. Dhayal Raj, G. Jayakumar, Adarsh Rag S
Abstract
High Resolution Image Download MS PowerPoint Slide Lanthanum oxide (La 2 O 3 ) nanoparticles stand out as promising photocatalysts due to their remarkable stability and photocatalytic properties. In this study, La 2 O 3 nanoparticles were synthesized via a hydrothermal method and explored how varying calcination time (3 and 5 h) influences their structural, morphological, optical, and catalytic properties. X-ray diffraction (XRD) confirmed stable hexagonal structure, with crystallite sizes increasing from 32.79 to 45.49 nm, while UV–vis absorption studies revealed that increasing calcination time led to a gradual decrease in bandgap energy from 4.6 to 4.4 eV, making the material more effective at utilizing light for pollutant degradation. When tested against a range of organic dyes, La 2 O 3 nanoparticles calcinated for 5 h exhibited the highest degradation efficiencies, due to their improved crystallinity and enhanced charge carrier movement. The photocatalytic process followed first-order kinetics, and recyclability tests showed that the nanoparticles retained their efficiency over multiple cycles. Radical scavenger tests confirmed that hydroxyl radicals ( • OH) and superoxide radicals ( • O 2 – ) were the dominant reactive species involved in dye degradation, affirming the key mechanism behind the observed photocatalytic performance. These results highlight how fine-tuning calcination time can significantly enhance La 2 O 3 ’s potential, making it an eco-friendly solution for wastewater treatment.