Promotion of Alumina Supported Cobalt Catalysts by Iron

Several alumina supported cobalt (Co), iron (Fe) mono metallic, and Co-Fe bimetallic catalysts were synthesized, characterized, and studied for the carbon dioxide (CO2) hydrogenation reaction. The catalysts were synthesized by coimpregnation and double-impregnation methods, and characterized by X-ray diffraction (XRD), ultraviolet-visible-near infrared (UV-vis-NIR), and diffuse reflectance infrared fourier transform (DRIFT) spectroscopy. The surface areas of the catalysts were also determined. Appropriate amounts of Fe promote the catalytic reactivity of alumina supported cobalt catalysts for the CO2 hydrogenation reaction. Furthermore, it was beneficial that this catalyst was synthesized by the double-impregnation method, where Fe was initially deposited, and then, Co was deposited on the alumina support. The hydrogenation of CO2 revealed the presence of formate species on the catalyst during reaction. It appears that iron promotes the supported cobalt catalyst by (i) protecting cobalt from strongly interacting with the alumina support and (ii) forming a Co-Fe alloy.