Reactions of Fe with H₂O and FeO with H₂. A Combined Matrix Isolation FTIR and Theoretical Study

Abstract

The study of the reactions of transition metal atoms with water is continued in this work. Here we report the study of the reactions of Fe with H2O and FeO with H2. In agreement with previous thermal atom experiments, laser-ablated Fe atoms reacted with H2O to form the FeOH2 and HFeOH molecules as characterized by matrix isolation FTIR spectroscopy. On photolysis, the Fe atoms could further insert into the OH bonds in H2O molecules with a stepwise pattern to form multi metal−oxo core species including HFeOFeH, HFeOFeOH, and possibly HFeOFeOFeH, which were identified by isotopic substitutions and density functional calculations. Reactions of FeO with H2 also lead to HFeOH as the primary product. In addition, a potential energy surface for the Fe + H2O ⇔ FeO + H2 reaction was constructed to elucidate the reaction mechanisms.