Unusual Fe-H bonding associated with oxygen vacancies at the (001) surface of Fe3O4

TL;DR

This study reveals that oxygen vacancies on Fe3O4 (001) surfaces lead to unusual Fe-H bonding instead of typical OH bonding, with implications for tuning surface chemical properties.

Contribution

It uncovers the link between oxygen vacancies and Fe-H bonding at Fe3O4 surfaces, supported by DFT calculations, highlighting a novel surface chemistry behavior.

Findings

Unusual Fe-H bonding occurs at oxygen vacancy sites.

OH bonding is favored on surfaces with fewer oxygen vacancies.

Bonding behavior can be tuned by controlling oxygen vacancy concentration.

Abstract

An unusual Fe-H bonding rather than conventional OH bonding is identified at Fe3O4 (001) surface. This abnormal behavior is associated with the oxygen vacancies which exist on the surface region but also penetrate deep into the bulk Fe3O4. In contrast, OH bonding becomes preferential as generally expected on an ozone processed surface, which has appreciably less oxygen vacancies. Such bonding site selective behavior, depending on oxygen vacancy concentrations, is further confirmed with DFT calculations. The results demonstrate an opportunity for tuning the chemical properties of oxide surfaces or oxide clusters.