Molybdenum tailored Co0/Co2+ active pairs on a perovskite-type oxide for direct ethanol synthesis from syngas

Abstract

Selective synthesis of ethanol from syngas under the Co-based catalysts is still challenging due to the hard of regulating the active site Co0 and Co2+ ratio. In this work, a series of CaTi0.9−xCoxMo0.1O3 (x = 0, 0.1–0.4) and CaTi0.7Co0.3O3 catalysts were prepared by using citric acid complexation method to promote the synthesis of ethanol. It was found that Mo species in the perovskite lattice can regulate the Co0 and Co2+ ratio through the domain-limiting effect of perovskite and the degree of Co reduction could be adjusted by changing the Co/Mo molar ratio. Among these investigated catalysts, the total selectivity of alcohols over the catalyst with the optimal Co/Mo ratio CaTi0.6Co0.3Mo0.1O3 reached 39.1%, with ethanol accounting for 74.7%, which was ascribed to the moderate and tightly bound ratio of dissociative to non-dissociative adsorption sites on the surface and the balance of CHx-CHy coupling and CO insertion.