Study on the effect of active sites of ethanol synthesis from syngas over RhCu bimetallic catalyst

Developing efficient and stable bimetallic catalysts has been a highly promising challenge for the direct synthesis of ethanol from syngas in recent years. In this study, a series of RhCu/P25 bimetallic catalysts with different Rh contents were prepared by combining the urea-assisted gel method and the impregnation method, and their performance in ethanol synthesis from syngas was studied. The results show that Rh-modified Cu-based catalyst can effectively promote the ethanol production. However, when the active sites of Rh and Cu are in close contact, the reaction products are mainly methane and methanol, and ethanol content is very low. This should be attributed to the inhibition of the adsorption of CO molecules on the Rh and Cu active sites. When the spatial distance between the Rh and Cu active sites is increased by physical mixing, the adsorption of CO molecules is significantly enhanced, and the catalytic activity and ethanol selectivity are improved.