Effect of copper source on the structure–activity of CuAl2O4 spinel catalysts for CO hydrogenation

Due to the complexity of the structure–activity relationship of the CuAl 2 O 4 spinel catalyst, optimization of the catalyst structure is a great challenge. In this paper, three different CuAl 2 O 4 spinel catalysts were prepared by the solid-phase method using copper hydroxide, copper nitrate, and copper oxide as the copper source, respectively, to study the difference in the structure of CuAl 2 O 4 spinel catalysts induced by the raw materials and the catalytic behavior for CO hydrogenation. The structure of CuAl 2 O 4 spinel catalyst was characterized by XRD, BET, SEM, TEM, H 2 -TPR and XPS. The activity of CO hydrogenation over the CuAl 2 O 4 spinel catalyst without pre-reduction was evaluated in the slurry reactor. The results demonstrated that different copper sources had obvious influence on the CuAl 2 O 4 spinel texture properties, surface enrichment degree, as well as decomposition and reduction ability, which further regulated the ratio of Cu + /Cu 0 and thus affected the catalytic performance, especially the alcohol distribution. The CuAl 2 O 4 spinel, employing copper hydroxide as the copper source, showed better selectivity of C 2+ OH, which was assigned to a higher ratio of Cu + /Cu 0 , along with larger pore size and pore volume. Moreover, the synergistic effect between Cu 0 and γ-Al 2 O 3 improved the selectivity of dimethyl ether.