Carboxylic acid induced restructuring of the Fe3O4(001) surface

Area of Science:

• Materials Science
• Surface Chemistry
• Catalysis

Background:

• Redox properties of Fe3O4 surfaces are crucial for catalysis.
• Fe3O4 surfaces undergo dynamic restructuring during reactions.

Purpose of the Study:

• Investigate structural changes on Fe3O4(001) during formic and acetic acid decomposition.
• Elucidate the interplay between carboxylic acid conversion and oxide surface restructuring.

Main Methods:

• Scanning tunneling microscopy (STM)
• X-ray photoelectron spectroscopy (XPS)
• Density functional theory (DFT) calculations

Main Results:

• Both acids form ordered carboxylate overlayers.
• Formic acid caused ~3% surface oxygen removal, creating elongated pits.
• Acetic acid induced ~20% oxygen removal, forming larger pits and indicating step-edge etching.

Conclusions:

• Lattice oxygen removal destabilizes Fe atoms, driving pit propagation and step formation.
• Atomistic insights into redox chemistry and morphological changes on Fe3O4 surfaces were provided.