Enhanced catalytic performance for direct synthesis of dimethyl ether from syngas over a La2O3 modified Cu-ZrO2/γ-Al2O3 hybrid catalyst

摘要

A series of hybrid catalysts were made by physically mixing Cu-ZrO2 and γ-Al2O3,for former it was modified with different loadings of La2O3 prepared by co-precipitation method.The catalysts were characterized by BET,XRD,N2O-adsorption,EXAFS,H2-TPR,NH3-TPD techniques and evaluated in the synthesis of dimethyl ether from syngas.The results show that La2O3 promoted catalysts displayed a significantly better catalytic performance compared with Cu-ZrO2/γ-Al2O3 catalyst in CO conversion and DME selectivity,and the optimum catalytic activity was obtained when the content of La2O3 was 12 wt％.The characterizations reveal that high copper dispersion,facile reducibility of copper particles and appropriate amount of acidic sites are responsible for the superior catalytic performance.