Identification of a Fe(OH)2-like phase in the core-shell structure of nano-zero-valent Fe and its evolution when interacting with Pd2+aq ions by Mo spacing diaeresis ssbauer spectroscopy, XPS, and TEM

Synthesized Fe@FeOx nanoparticles (NPs) were fully characterized by spectroscopic techniques and (scanning) transmission electron microscopy to resolve the presence of a Fe(OH)2-like phase. The different phases detected in the core-shell nanostructure of these NPs were corroborated by Mo center dot ssbauer and X-ray photoelectron spec-troscopies. Metallic iron (Fe0), ferrous (FeII) hydroxide, magnetite (FeIII2FeIIO4), and a top layer of ferric (FeIII) oxide were identified. Interestingly, ferrous hydroxide reacted with Pd2+aq upon coating of the supporting cor-e-shell material when Pd was added to produce Fe@FeOx/Pd NPs.

Automated summary

Synthesized Fe@FeOx nanoparticles were characterized using various spectroscopic techniques and microscopy. Different phases, including metallic iron, ferrous hydroxide, magnetite, and ferric oxide, were identified in the core-shell structure. Upon coating the supporting material, the ferrous hydroxide reacted with Pd2+aq to form Fe@FeOx/Pd nanoparticles.