Characterization of fused Fe–Cu based catalyst for higher alcohols synthesis and DRIFTS investigation of TPSR

Fused Fe–Cu based catalyst for higher alcohols synthesis (HAS) is characterized by XRD, TG–DTA, H2-TPD and DRIFTS of CO adsorption. The results of XRD reveal that the fused Fe–Cu based catalyst consists of Cu2O, CuFeO2 and CuFe2O4 species. After reduction, the metallic Fe and Cu are the main species, but minor CuFeO2 and CuFe2O4 species are also present. H2-TPD shows that in comparison with the pure Fe- or Cu-based sample, the ability of Fe–Cu based catalyst for activation of H2 is higher and the stronger metal–hydrogen bonds are formed. DRIFTS of CO adsorption indicates that CO is adsorbed on both metal and metal ion sites, where the dissociation of CO to C* and O* species and the formation of CO2 are observed. In situ DRIFTS investigation of CO + H2-TPSR over the Fe–Cu based catalyst shows that the dissociative activation of H2 is more difficult than the activation of CO, and carbonaceous and hydrocarbon fragment species only appears after the dissociative activation of H2. In addition, HAS over the Fe–Cu based catalyst is very complicated, where various intermediates including = CH2, − CHO, − OOCH, − OH and − C(= O)–R exist.