Sulfidation of Magnetite Nanoparticles - Following the Polysulfide Pathway
The in‐situ sulfidation of sub‐10 nm sized Fe3O4 and partial‐substituted CoxFe3–xO4 (x = 0.25–0.75) nanoparticles by hot‐injection of sulfur dissolved in oleylamine (OA) is strongly time‐ and temperature dependent. Fe3O4 nanoparticles are completely converted within 5 minutes into Fe3S4 nanoparticles with preservation of the spinel structure at 250 °C, whereas higher reaction temperatures and prolonged reaction times result in additional sulfur uptake and formation of pyrite FeS2 nanoparticles. The formation of the cubic (Co,Fe)S2 phase was observed in sulfidation reactions of CoxFe3–xO4, even with low Co substitution levels (x = 0.25). The chemical composition, morphology, and phase purity of the resulting nanoparticles were investigated by EDX, XRD, TEM, and XPS.
Dedicated to Prof. Wolfgang Bensch on the occasion of his 65th birthday.