The roles of various Fe–Cu bimetallic nanoclusters in controlling the C2 selectivity for the CO reduction reaction – a DFT study

The unique microstructure of the Cu₁₃ nanocluster with distinct catalytic properties from general metals has been used to study the selectivity effect on oxygenated hydrocarbons. The strong synergistic promotion of Fe-Cu bimetallic nanocatalysts has been used to convert CO₂ or CO to olefins via selective reduction. Unveiled using DFT, we have characterized the CO reduction capabilities of a series of Fe-Cu bimetallic nanocatalysts and further investigated to search for the possible intermediates along the CO reduction pathway. Fe_nCu_13-n clusters with different compositions (n = 1, 2, 7, 11 and 12) are selected to represent the Cu dominant, the equal ratios, and the Fe dominant conditions in the simulations. Only the Fe-dominant clusters, particularly Fe₇Cu₆ and Fe₁₁Cu₂, show a preference for the formation of the COCHO intermediate. The improvement in selectivity is crucial to the successful design of catalytic systems for carbon-neutral processes. Thus, we incorporated carbon nanotubes (CNTs) to stabilize Fe₇Cu₆ and Fe₁₁Cu₂ nanoclusters, with the goal of enhancing the reactivity of the CORR. Compared to the isolated nanoclusters, the Fe₁₁Cu₂/CNT not only reduces the activation energy for CO⋯CHO bond formation and the reaction energy for COCHO intermediate formation but also exhibits more stable thermodynamic properties for ethanol generation.