The Influence of Active Phase Composition and Reaction Temperature on the Catalytic Properties of K-Promoted Co–Ni/CeO2 Catalysts in the Steam Reforming of Ethanol

Potassium promoted cobalt–nickel catalysts were characterized and applied to the steam reforming of ethanol (SRE). SRE studies at 420 °C show that the catalysts containing more nickel in the active phase exhibited better catalytic properties. After SRE, the encapsulating carbon deposit was dominated on the cobalt catalyst while the fibrous deposit was dominated on the nickel catalyst. The encapsulating carbon showed mainly graphite structure which completely deactivated cobalt particles in the process while the amorphous structure was dominated in the fibrous deposit and had no significant effect on catalyst deactivation. An increase in reaction temperature to 580 °C resulted in improved activity, selectivity and stability of catalysts in the SRE. Furthermore, the production of carbon on the cobalt catalyst was reduced. While on the nickel catalyst after reaction two forms of fibrous deposits with different structures were observed. The type and structure of the carbon deposit had a significant impact on the catalyst stability.