Effect of ZnO morphology on the performance of CuZnAl slurry catalysts for the ethanol synthesis from syngas

Abstract

The impact of nanomaterial morphology on the structures of catalysts has drawn intense interest. Based on previous work, we discovered that ZnO plays an essential role in the ethanol production. In this research, we discussed the impact of ZnO with different morphology (rod-like, granular-like and flower-like) on the performance of CuZnAl slurry catalysts for the ethanol production. The catalytic performance was evaluated at H2/CO = 2, 250 °C and 4.0 MPa, and the catalyst structures were tested by XPS, in situ DRIFT and so on. The results show that CuZnAl catalysts prepared with rod-like and granular-like ZnO show the better selectivity of methanol and DME, which is assigned to the highly dispersion of Cu species and more quantity of acidic sites, respectively. CuZnAl catalyst prepared with flower-like ZnO possesses the higher total alcohol selectivity (45.0%) and the highest ethanol proportions in total alcohol (50.0%). Flower-like ZnO that exposed more polar (002) facets results in more surface defect structures (oxygen vacancy, Zn(2-δ)) and high ratio of Cu0/Cu+ in this catalyst, all of which are related to the formation of ethanol.