Fe modified CuMnZrO2 catalysts for higher alcohols synthesis from syngas: Effect of calcination temperature

The effect of iron on the structure and catalytic performance was investigated by comparison of iron-promoted and un-promoted catalysts calcined at different temperature. It was found that, when the catalysts were calcined at different temperature, the change of metal-support interaction strongly influenced the surface and crystal structure of the catalysts and hence its catalytic performance. Low calcination temperature yielded poorly crystallized catalysts and favored the formation of a Cu(OH)2-like structure, which was highly dispersed. For the CuMnZrO2 catalyst, with the rise of calcination temperature, surface area and dispersion of copper decreased, and the crystallization of zirconia occurred. Nevertheless, the TOF showed a maximum on the catalyst calcined at 873 K due to the increase of the copper-zirconia interaction. The presence of iron could suppress agglomeration of copper species and crystallization of amorphous zirconia. The dispersion of copper was enhanced. However, overall catalytic activity was suppressed. On the one hand, the increase of iron-zirconia interaction with the rise of calcination temperature suppressed the interaction between copper species and zirconia. On the other hand, the interaction between iron and zirconia hindered the reduction of iron oxide, and then copper-iron interaction weakened, which reduced the active sites for higher alcohol formation.