Janus Au–Fe2.2C Catalyst for Direct Conversion of Syngas to Higher Alcohols

Higher alcohol synthesis (HAS) direct from syngas using Fe-based catalysts is quite promising, but there are still problems in the construction of intimate-contact and stable dual sites to obtain satisfactory higher alcohol selectivity and space time yield (STY). Herein, a series of Au–Fe2.2C catalysts derived from monodisperse Janus Au–Fe3O4 nanoparticles with different Fe/Au ratios were prepared. The optimal catalyst with a Fe/Au molar ratio of 11.6 achieved the most Janus nanoparticles and exhibited the highest STY toward higher alcohols of 0.195 g gcat–1 h–1 and excellent catalytic stability over 200 h. The superior performance of this catalyst was attributed to the unique Au–Fe2.2C Janus structure, which could enhance both CO insertion and CO dissociation as well as their synergistic effect. The correlation of the CO adsorption behavior and STY toward alcohols was established as well, indicating that the balance between CO nondissociated adsorption and CO dissociated adsorption played an important role in enhancing the alcohol formation. Moreover, the strong interaction between Au and iron species in Janus nanoparticles could facilitate the formation of ε′-Fe2.2C and benefit the stability of the catalyst. These results may provide new ideas for the design and fabrication of high-performance catalysts with dual sites for HAS.