The Effect of Ag in the Cu/ZrO2 Performance for the Ethanol Conversion

Abstract

In this work, 10 wt% Cu on ZrO2 was modified with 0.3, 2, and 5 wt% of Ag. The addition of Ag led to a decrease in the Cu reduction temperature, suggesting the formation of an alloy. CO-DRIFTS and XPS (Cu 2p, Ag 3d, and Zr 3d) analyses showed that Ag addition to Cu/ZrO2 increased the dispersion of the Cu particles, leading to a progressive decrease in the Cu0/Cu+ ratio (i.e., higher oxidation degree).The catalysts were tested in the ethanol conversion in inert atmosphere and the major products were acetaldehyde and ethyl acetate. By increasing the Ag loading, the catalysts progressively decrease activity, and the product distribution was also affected. While Cu/ZrO2 presented the highest selectivity to ethyl acetate and lowest to acetaldehyde, the increase in the Ag loading (consequently lower Cu0/Cu+ ratio), led to an increase in the acetaldehyde selectivity at the expenses of the ethyl acetate selectivity.