Performance of Cu-Co Bimetallic Catalysts for Catalytic Syngas to Produce Higher Alcohols: Influence of the Preparation Methods, Cuco Ratios, and Carriers

Abstract

Higher alcohols (C2+ mixed alcohols) have attracted much attention due to their high application value in fuel, chemical industry and environment. Producing higher alcohols from synthesis gas accords with atomic economy, whereas the performance of related catalysts is not acceptable. To enhance the catalyst reactivity, product selectivity and the stability of the catalysts, the influence of the preparation methods, Cu-Co ratios, and carriers on the performance of Co-Cu bimetallic catalysts are investigated. The structure and physicochemical characteristics of the catalyst are mainly characterized by ICP-OES XRD, BET, TEM, and H2-TPR. First, the Co-Cu bimetallic catalysts (CoxCu1/SiO2) were first prepared by impregnation method. The results show that the selectivity of catalysts to alcohols can be affected by changing the molar ratio of copper to cobalt. The Co2Cu1/SiO2 catalyst showed the best performance at GHSV=8000 mL•gcat-1•h-1, with a selectivity of 51.9% for ROH and 35.5 wt% yield for C2+ alcohol. On this basis, Co2Cu1-Z@SiO2 catalyst with up to 45% metal loading capacity was prepared by the original growth method. Under the same catalytic reaction condition, the CO conversion rate is 75.6%, the ROH selectivity is 61.3%, and the stability is good within 200 h. In addition, Co2Cu1-Z@SiO2 catalyst showed good stability due to the channel limitation of the support. This provides a new exploration for further development of bimetallic catalysts with better performance, more stable and higher selectivity in the field of synthesis gas conversion to higher alcohols.

Keywords: Syngas, Higher alcohols, CoCu bimetallic catalyst, Influence factors