Density Functional Theory Studies of the Structure Sensitivity of Ethanol Oxidation on Palladium Surfaces

In this work, the adsorption behaviors and oxidation mechanisms of ethanol on palladium surfaces, including the closed-packed Pd(111), the stepped Pd(110), and the open Pd(100), are investigated using density functional theory (DFT). By exploring the electronic properties of different single palladium surfaces, the adsorption behaviors, and the first step dehydrogenation of ethanol, it is found that Pd(100) is the best surface for the dissociation of ethanol molecules. The reaction network of ethanol oxidation on the Pd(100) surface is then investigated to illustrate the complete reaction paths. The results demonstrate for the first time that the activity and selectivity of ethanol oxidation on palladium are highly structure-sensitive. In addition, the effect of OH species on the reaction paths is also studied. The results show that the adsorbed OH species assists in lowering the barrier energy of the CH2CHOH species oxidizing to the acetic acid species.