The Roles of Various Fe-Cu Bimetallic Nanoclusters in Controlling the C2 Selectivity for CO Reduction Reaction - A DFT Study

Abstract

The unique microstructure of 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 by 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. The FenCu13-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 CORR. Compared to the isolated nanoclusters, 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.