Heteronuclear nanoparticles supported hydrotalcites containing Ni(II) and Fe(III) stable photocatalysts for Orange II degradation

Hydrotalcites containing Ni(II) and Fe(III) was synthesized using co-precipitation method to demonstrate their use as a support material for the homogeneous deposition of Au and Au-Pd nanoparticles via sol-immobilization. Detailed characterization performed by UV–Vis, ATR-FTIR, TGA, Mössbauer spectroscopy, SEM, Cryo-TEM, BET analysis evidenced the structural, morphological and textural properties of the passive support and decoration of nanoparticles on the surface of LDH and evidenced the property to be used as photocatalysts. These materials proved to be efficient photocatalysts for the degradation of environmentally important Orange II dye (OII) as a model pollutant. Different experimental parameters influencing the photocatalytic activity viz., catalyst dosage, initial dye concentration and reusability of the catalyst were studied. Langmuir-Hinshelwood model was used to analyze the kinetics of the photocatalytic process. Heteronuclear Au-Pd nanoparticles immobilized on NiFeCO₃ LDH was found to be the best photocatalyst degrading about 95% of the dye (25 mg/L) after 60 min and this activity remains to be nearly the same after recycling the catalyst. This enhancement in the activity was attributed to the presence of Au-Pd Nps, with specific surface area (80 m²/g), and band gap (2.7 eV). Our study shows the prepared photocatalyst anticipates being a promising candidate for other photocatalytic applications.