Preparation, reduction, and CO chemisorption properties of a cyanide-derived Fe/Al 2O 3 catalyst

Abstract

A supported iron catalyst is prepared by precipitation of an iron hexacyanoferrate complex onto γ-alumina. Removal of the cyanide ligands by oxidation at 563 K results in the formation of highly dispersed iron(III) oxide particles. The reduction of the oxidic precursor proceeds via a support stabilised Fe 1 − x O phase as revealed by in situ magnetization measurements and Mössbauer spectroscopy. Upon exposure of the reduced and subsequently evacuated catalyst to carbon monoxide at room temperature, both linearly and bridged-bonded carbon monoxide species are observed by infrared spectroscopy at wavenumbers of 1985 cm −1 and 1980-1700 cm −1, respectively. A fraction of the carbon monoxide reacts with irreversibly chemisorbed hydrogen to formate and small hydrocarbons, which remain bonded on the surface of the iron particles.