DFT study of key elementary steps for C2+ alcohol synthesis on bimetallic sites of Cu-Co shell-core structure from syngas

Abstract To reveal the regulating mechanism of Cu-Co bimetallic catalyst for the conversion of syngas, several Cu-Co bimetallic sites are built to investigate their impacts on the key elementary steps involved in the higher alcohols synthesis using the DFT method. Species are categorized into three types to discuss the adsorption behaviors of them, i.e., CH x (x = 0–3), CH x O (x = 1–3), and CH x CO (x = 1–3). The concept of Bond Order (BO) is used to correlate binding energies (BEs). Hydrogenation of CH x O (x = 0–2), CO insertion into CH x (x = 1–3) and CH x O (x = 1–3) decomposition are considered as the key elementary steps in the work and investigated on all metallic (Cu9) and bimetallic surfaces (Cu9@, Cu8@, Cu8@_2, Cu6@). Then, detailed reaction network are investigated on the three different types of bimetallic site, Cu9@, Cu8@ and Cu6@. Catalytic properties of Cu9@, cu8@ and Cu6@ are discussed and compared, and mechanism that bimetallic site control the pathway is illustrated. Furthermore, effects of sublayers are illustrated by comparing the results of two pairs of surface sites, Cu9 and Cu9@, Cu8@ and Cu8@_2, where the surface composition are the same but sublayer compositions are entirely different.