Dimethyl ether synthesis on the admixed catalysts of Cu-Zn-Al-M (M = Ga, La, Y, Zr) and γ-Al 2O 3: The role of modifier

Abstract

Dimethyl ether synthesis has been conducted on the admixed catalysts of Cu based catalysts (for methanol synthesis) and γ-Al 2O 3 (for methanol dehydration). The Cu-Zn-Al-M (M = Ga, La, Y, Zr) hydrotalcite-like structures as catalyst precursors for methanol synthesis part of the admixed catalysts are synthesized by the co-precipitation method. The physico-chemical characteristics of the catalysts are analyzed by BET-surface area, XRD, TPR, SEM/EDS, XPS and N 2O pulse chemisorption studies. DME synthesis experiments showed that the CO conversion and DME yield are linearly correlated with Cu metal surface areas of Cu based catalysts admixed with γ-Al 2O 3, indicating that methanol synthesis rate can control the overall DME synthesis rate. The yttrium-modified Cu-Zn-Al admixed catalysts showed the superior activity with a DME yield of 47.7% to other Cu-based catalysts. The reason may be attributed to the increase in Cu metal surface area by the addition of yttrium.