Ternary copper-cobalt-cerium catalyst for the production of ethanol and higher alcohols through CO hydrogenation

A series of highly dispersed carbon nanotube (CNT)-supported copper-cobalt-cerium catalysts were prepared using a facile and effective co-impregnation method. The catalysts were then examined for their ability to selectively convert syngas into ethanol and higher (C₂₊) alcohols with a narrow range distribution. Superior selectivity values of 31.6% and 60.2% for the formation of ethanol and C₂₊ alcohols, respectively, were achieved over the CuCoCe/CNTs catalyst. These values were considerably higher than those achieved over a Cu-Co bimetallic catalyst (i.e., 16.6% and 29.7%). The addition of ceria alters the electronic and geometric interactions with the cobalt species, thereby promoting the reduction of CoO and the formation of a Co-CeO_2-x interface as a new active site for enhancing CO dissociation and terminating carbon chain growth by oxygenation. In contrast, the CNTs serve as reactors to ensure intimate contact among the metal particles at the nanoscale. The structure-performance correlation studies suggest that the formation of the Co-CeO_2-x interface plays a key role in determining the distribution of short-chain alcohols.