The role of surface defects in the adsorption of methanol on Fe3O4(001)

TL;DR

This study investigates how surface defects on Fe3O4(001) influence methanol adsorption, revealing that defects serve as active sites for hydroxyl and methoxy formation, with specific desorption and reaction behaviors identified.

Contribution

It provides detailed identification of defect sites responsible for methanol adsorption and their role in subsequent desorption and reaction processes on Fe3O4(001).

Findings

Methanol adsorbs exclusively at defect sites forming hydroxyl and methoxy groups.

Recombinative desorption occurs around 300 K.

Disproportionation to methanol and formaldehyde occurs at 470 K.

Abstract

The adsorption of methanol (CH3OH) at the Fe3O4(001)-c(2x2) surface was studied using X-ray photoelectron spectroscopy (XPS), scanning tunneling microscopy (STM), and temperature-programmed desorption (TPD). CH3OH adsorbs exclusively at surface defects sites at room temperature to form hydroxyl groups and methoxy (CH3O) species. Active sites are identified as step edges, iron adatoms, antiphase domain boundaries in the c(2x2) reconstruction, and above Fe atoms incorporated in the subsurface. In TPD, recombinative desorption is observed around 300 K, and a disproportionation reaction to form methanol and formaldehyde occurs at 470 K.