Bimetallic Nano Cu-Co Based Catalyst for Direct Ethanol Synthesis from Syngas and Its Structure Variation with Reaction Time in Slurry Reactor

The catalytic performance of Cu-Co/Al2O3 in the slurry reactor for direct ethanol synthesis from syngas was investigated. The reduced catalyst and catalyst reacted for 100, 300, 500, and 750 h were characterized by using XRD, TEM, EDS, BET, and ICP-MS techniques. Compared with that in the fixed-bed reactor, the catalyst in the slurry reactor exhibited higher selectivity to ethanol, which was above 70 wt % in the total alcohols. The structure variation of the bimetallic Cu-Co with reaction time is that CuCo2O4 was transformed into Cu-Co alloy after reduction, and Cu-Co alloy was decomposed into Cu and CO after reaction for 100 h. After reaction for 300 h, Co2C started to generate and Cu@Co@Co2C was formed as reacted for 500 h. All of Cu-Co alloy, Cu@Co, and Cu@ Co@Co2C are highly selective to ethanol, which was maintained for 750 h: Meanwhile, the slurry solvent of PEG-400 is another reason for the high ethanol selectivity.