沉淀方法对FeMnCu/ZnO合成低碳醇催化剂性能的影响

The FeMnCu/ZnO catalysts for higher alcohols synthesis were prepared by coprecipitation and sequential precipitation methods. The texture and structure properties of FeMnCu/ZnO catalysts were characterized by ICP, BET, XRD, and TPR. The catalytic activity for C1~5 alcohol synthesis was determined in a fixed bed flow reactor system. The results showed that the catalytic performance of the catalysts was influenced by the precipitation methods remarkably. The alcohol yield and alcohol selectivity of sequential precipitation catalysts were obviously higher than that prepared by coprecipitation method. The alcohol selectivity of 33.5% with C2+ alcohol selectivity of 31.72% was obtained over “Fe atop Cu” catalyst under the reaction condition of T=503K，p=8.0MPa，GHSV=8000h－1，H2/CO＝2(volume ratio). It was found that sequential precipitation exhibited larger pore size, which could be favorable for long chain molecules to diffusion. The catalysts prepared by sequential precipitation method showed better dispersion of CuO and ZnO. Therefore, the performance for higher alcohols synthesis over catalysts prepared by sequential precipitation can be promoted. The copper ions in sequential precipitation were found to be reducible as compared with coprecipitation catalyst due to their initial temperature of reduction. Combined with the performance of the CO hydrogenation, better performance for higher alcohols over catalysts prepared by sequential precipitation can be ascribed to a mount of reducible Cu species.