Effect of promoter and CO₂ content in the feed on the performance of CuFeZr catalyst in the synthesis of higher alcohol from syngas

The effect of various promoting additives (Mn, Zn, Co) on the performance of CuFeZr catalyst in the synthesis of higher alcohol from syngas was investigated. The results of nitrogen physisorption, XRD and H₂-TPR characterization show that these additives can reduce the particle size and enhance the surface basicity and the adsorption capacity towards CO. Especially, the doping of Zn in the CuFeZr catalyst can effectively enhance the interaction between Cu and Fe, strengthen the surface basicity, and improve the reducibility and CO adsorption ability. For the synthesis of higher alcohol from syngas over the CuFeZr catalyst, the catalytic evaluation results in a fixed bed reactor illustrate that the activity and selectivity to alcohols are greatly enhanced by the addition of Zn promoter; the space time yield (STY) of ROH is increased from 0.026 to 0.071 g/(g_cat·h). Meanwhile, it was found that CO₂ in the feed can improve the CO conversion as well as the STY to alcohols and hydrocarbons, but suppress the chain growth and decrease the ratio of olefin to paraffin; proper amount of CO₂ (2.5%) is beneficial to the formation of alcohols and hydrocarbons of short chains.