La1−xKxFe0.7Ni0.3O3 catalyst for ethanol steam reforming—The effect of K-doping

Abstract

Coking is the critical problem for catalysts for steam reforming of ethanol (SRE). Several techniques have been reported for improving the ability to prevent coking of catalysts, such as adding alkaline to balance the acidic sites on the support, using support which can generate oxygen vacancies and using bimetallic catalysts. In this work, we try to improve the ability to prevent coking of this kind of catalyst by doping additives to modify the active component, which has not been attracted attention for SRE catalysts yet. La1−xKxFe0.7Ni0.3O3 (x=0, 0.05, 0.1) with perovskite structure was prepared by citric acid complexation method, and after reduction K-doped Ni/LaFeO3 catalysts were obtained. The catalytic performance including the ability to prevent coking and sintering over the catalysts were investigated. The catalysts were characterized by using X-ray diffraction, transmission electron microscopy, thermal analysis techniques and X-ray photoelectron spectroscopy analysis. The results indicate that the K-doped catalysts are very active, highly selective to hydrogen, as well very stable for SRE reaction. The doping of potassium can also restrain the sintering of nickel. The doping of K improved the ability to prevent coking of the catalyst markedly, which is attributed to the electron donation effect of potassium to nickel and this donation effect can promote the ability for breaking CC bond on the metal nickel sites.