CuZnAl precursor was prepared by coprecipitation sedimentation method and modified by addition of polyethylene glycol (PEG600). Slurry catalyst was then obtained by heat-treatment using complete- liquid phase technology. The performance of the catalysts for the direct synthesis of dimethyl ether from syngas was evaluated in a slurry reactor. Characterization of the catalysts was carried out by powder X-ray diffraction, H₂ temperature-programmed reduction, temperature-programmed desorption of ammonia and X-ray photoelectron spectrometry. The results indicated that PEG600 could effectively promote the reduction of the copper species in catalysts and improve the Cu₂O dispersion. The amount of acid and the acidic distribution of catalyst were also changed due to addition of PEG600. Moreover, marked influences were found on methanol synthesis and dehydration capability when PEG600 was added in different way. A significant increase of activity was achieved when the catalyst was prepared in the condition of adding 0.5 wt% PEG600 into the solution of copper nitrate and zinc nitrate. This was attributed to the stable Cu₂O with small grain size formed during the heat-treatment process.

Key words: polyethylene glycol, coprecipitation sedimentation method, complete liquid-phase technology, CuZnAl slurry catalyst, dimethyl ether