Carbon oxide hydrogenation over silica-supported iron-based catalysts: Influence of the preparation route

A series of silica-supported iron samples has been prepared by the microemulsion technology. The samples were characterized by temperature programmed reduction (TPR), UV–vis spectroscopy, N2 adsorption isotherms, X-ray photoelectron spectra (XPS), SEM and transmission electron microscopy (TEM) microscopy and tested in the carbon monoxide and carbon dioxide hydrogenation reactions. Although all samples have similar composition and metallic loading, the preparation route was crucial for the actual nature of the samples, tuning also their catalytic performance. The main result of the preparation route was the extension of the degree of the interaction between the active phase and the support. As a consequence, samples where a metal–support interaction was promoted showed a lower reducibility and therefore a lower catalytic activity. The addition of Mn, Cu and K promoters improves the catalytic performance in carbon monoxide hydrogenation. The low activity of the samples in carbon dioxide hydrogenation is due to their low reverse water–gas shift activity.