Effect of copper precursors to the activity for dimethyl ether synthesis from syngas over Cu-ZnO/γ-Al₂O₃ bifunctional catalysts

The effect of precursors, such as copper nitrate, acetate, and chloride, on the bifunctional Cu-ZnO/γ-Al₂O₃ catalysts was investigated for the direct dimethyl ether (DME) synthesis from syngas. The catalysts were characterized by measuring the reducibility and the surface area of metallic copper, together with their acidity. The well-dispersed copper particles with a high reducibility as well as a large amount of weak acidic sites on the bifunctional Cu-ZnO/γ-Al₂O₃ catalysts, prepared from a copper acetate precursor, are responsible for its high catalytic activity. The quantity of the acidic sites is a more crucial factor for obtaining a high DME yield than the surface area of metallic copper on the bifunctional catalyst.