Synthesis of Ni-Fe PBA derived NiO/Fe3O4 nanocomposites for chemocatalytic water oxidation and photocatalytic degradation of organic dyes

In this study, Ni-Fe-based Prussian Blue Analogues (Ni-Fe PBA) served as precursors, giving rise to a NiO/Fe 3 O 4 -based bimetallic catalyst that underwent comprehensive examination for both chemocatalytic water oxidation and photocatalytic degradation of organic dyes. The morphologies and chemical compositions of the precursor and resultant bimetallic catalysts were thoroughly characterized using XRD, SEM, XPS, mapping, and FTIR techniques. The results indicated that the catalytically active center is the NiO/Fe 3 O 4 -based bimetallic nanocomposite. The in-situ-synthesized bimetallic catalyst demonstrated remarkable catalytic oxidation activity when evaluated with Sodium Persulfate (PS) as an oxidant. Oxygen evolution results revealed an impressive catalytic water oxidation activity, with an O 2 production rate of approximately 1594.3 µmol·g −1 ·h −1 . Moreover, the NiO/Fe 3 O 4 catalyst was utilized as a heterogeneous photocatalyst to activate photosensitizer (PS) for the two azo dye’s deterioration caused by the exposure to visible light. Both organic dyes were photocatalytically degraded with great efficiency when Fe 3 O 4 and NiO were combined because they increased the catalyst’s capacity to absorb light. Electron Spin Resonance (ESR) and radical trapping studies revealed that sulfate (SO4· - ) and hydroxyl (OH·) radicals played pivotal roles. The degradation mechanism and pathway for Rhodamine B (RhB) were also elucidated. The exceptional recyclability and stability of the NiO/Fe 3 O 4 catalyst make it particularly promising for potential applications in water treatment, addressing challenges related to energy sustainability and environmental toxicity.