Cobalt-Based Catalysts for Ethanol Steam Reforming: An Overview

Cobalt has been extensively studied for its use as an alternative catalyst to noble metals for ethanol steam reforming. Among the many other catalyst supports tested, cerium oxide contributed significantly to the catalytic activity and stability of the Co/CeO2 catalyst as a result of its high oxygen mobility and storage capacity. In this paper, an overview of the research conducted in our laboratory during the past decade on ethanol steam reforming using the Co/CeO2 catalyst is presented. The role of the support oxygen mobility and storage capacity of the Co/CeO2 catalyst and how the addition of calcium to the ceria support changes the oxygen vacancies in the catalyst structure are discussed. Results from in situ characterization techniques, such as X-ray diffraction, Raman spectroscopy, X-ray absorption near edge structure, and extended X-ray absorption fine structure, are summarized, showing the evolution of the cobalt phases during synthesis, pretreatment, and ethanol steam reforming reaction. Also, how the synthesis parameters, such as synthesis method, impregnation medium, choice of cobalt precursor, support morphology, and particle size, could alter the catalytic activity and selectivity have been outlined.