Cobalt-iron Oxide, Alloy and Nitride: Synthesis, Characterization and Application in Catalytic Peroxymonosulfate Activation for Orange II Degradation

Abstract

Abstract:In meeting the need for environmental remediation in wastewater treatment and the development of popular sulfate-radical-based advanced oxidation processes (SR-AOPs), a series of Co/Fe-based catalysts with confirmed phase structure were prepared through extended soft chemical solution processes followed by atmosphere-dependent calcination. Powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and 57 Fe Mössbauer spectroscopy were employed to characterize the composition, morphology, crystal structure and chemical state of the prepared catalysts. It was shown that calcination in air, nitrogen and ammonia atmospheres generated Co-Fe catalysts with cobalt ferrite (CoFe 2 O 4 ), Co-Fe alloy and Co-Fe nitride as dominant phases, respectively. The prepared Co/Fe-based catalysts were demonstrated to be highly efficient in activating peroxymonosulfate (PMS) for organic Orange II degradation. The activation efficiency of the different catalysts was found to increase in the order CoFe 2 O 4 < Co-Fe nitride < Co-Fe alloy. Sulfate radical was found to be the primary active intermediate species contributing to the dye degradation for all the participating catalysts. Furthermore, a possible reaction mechanism was proposed for each of the studied catalysts. This study achieves progress in efficient cobalt-iron catalysts using in the field of SR-AOPs, with potential applications in environment remediation.

Magnetic recyclable CoFe2O4@PPy prepared by in situ Fenton oxidization polymerization with advanced photo-Fenton performance

“…However, the traditional Fenton reaction encounters problems such as low pH conditions, sluggish Fe 3+ reduction kinetics and secondary pollutants caused by mass production of slurry containing Fe 3+ . Therefore, heterogeneous Fenton systems 1–3 in which Fe 2+ of the catalyst was replaced by Fe( ii ) active sites from solid iron metals, 4 alloys, 5–7 oxides 7–9 and other compounds are developed for better recyclability. Nevertheless, the rapid re-generation of Fe( ii ) active site from Fe( iii ) on the surface of heterogeneous Fenton catalysts remains challenges.…”

Surface Diels–Alder adducts on multilayer graphene for the generation of edge-enriched single-atom FeN4 sites for ORR and OER electrocatalysis

“…The core-level Fe 2p XPS spectra of MLG-dppz@Fe were deconvoluted into three peaks: Fe 2p 3/2 and Fe 2p 1/2 regions at 712.5 eV and 725.8 eV, respectively, assigned to the Fe(III) formal oxidation state, and the characteristic Fe 3+ 2p 3/2 satellite peak centered at 719.1 eV, in agreement with previously reported studies. [98][99][100][101][102][103] The Fe 2p XPS spectra of MLG-dppz@Fe(240N 2 ) and MLGdppz@Fe(240air) were tted into ve characteristic contributions (Fe 2+ 2p 3/2 , Fe 3+ 2p 3/2 , satellite peak, Fe 2+ 2p 1/2 , and Fe 3+ 2p 1/2 ). The generation of Fe 2+ species and the binding energies at ca.…”

Fabrication of Iron Oxide Nanoparticles via Submerged Photosynthesis and the Morphologies under Different Light Sources

“…The peaks located at 711.9-712.1 eV, 710.4-710.7 eV, and 709.1-709.4 eV are the assigned as FeOOH, Fe(III) in Fe 2 O 3 , and Fe(II) peak, respectively. [28][29][30][31] The peak intensity and area changes indicated that Fe(II) mostly existed in the specimens obtained under dark conditions (Figs. 4(a), 4(b)), while more FeOOH and Fe 2 O 3 exist under light irradiation compared with that under dark conditions.…”