Direct conversion of syngas to ethanol over Rh-based and Cu-based tandem catalyst: Effect of Cu crystal plane

Ethanol direct synthesis from CO hydrogenation over a tandem system composed of Rh/P25 and different facet Cu2O nanocrystals are explored. The effect of Cu crystal plane is hindered by the complexity of the ethanol synthesis from syngas and the lack of adequate crystal plane structure data. In this work, the tandem catalysts Rh/P25 and the crystal-plane-controlled Cu2O (cubes, octahedral Cu2O, and 18 facet nanocrystals) are used to catalyze syngas to ethanol, in which 18 facet Cu2O exposing {1 0 0}&{1 1 0} crystal planes is the more selective and catalytic activity for ethanol than Cu2O cubes {1 0 0} and Cu2O octahedral {1 1 1} crystal planes. The tandem system consisting of Rh/P25 and 18 facet Cu2O NCs can afford the best catalytic activity (43.4%) and an ethanol selectivity of 18.7%. It is demonstrated that the selectivity and activity of the ethanol synthesis from syngas can be enhanced by tandem catalyst Rh-based and the selective exposure of Cu2O nanocrystals with specific crystal planes. These results reveal that the selective exposure of Cu2O nanocrystals with specific crystal planes is very helpful for enhancing the catalytic performance using tandem reaction of Rh-based and Cu NCs catalysts for ethanol synthesis from synthesis gas.