In situ IR studies on ethanol transformations over CuO, CuO/ZrO2 and CuO/ZrO2/ZnO catalysts modified with NiO

Abstract

Catalytic conversion of ethanol is a promising method of hydrogen production. This reaction is catalysed by metals and oxides. One of such catalysts are mixed oxides CuO/ZrO2 (Cu/Zr) with the addition of other oxides. We studied by IR spectroscopy the transformations of ethanol on Cu/Zr with addition of ZnO, NiO. Additionally, the temperature-programmed reaction of ethanol on these oxides was followed. We studied also the temperature-programmed reduction of these oxides with hydrogen. The reaction of ethanol on CuO produced acetaldehyde and water but not hydrogen, indicating, that ethanol was oxidized over this oxide. On the other hand, acetaldehyde was produced from ethanol both by oxidation and dehydrogenation over Cu/Zr (both water and hydrogen were produced). Acetaldehyde was subsequently oxidized to acetic acid, which was next transformed to acetone. The addition of ZnO facilitated the formation of acetone evidencing that ZnO is effective catalyst for the reaction acetic acid → acetone. The addition of NiO caused the decomposition of acetaldehyde to methane and CO.