2-propanol oxidation at the Co3O4 (001)/H2O Interface: the role of Temperature, Surface Composition and Electrochemical Environment

Ab initio molecular dynamics simulations of a single hydrated 2-propanol molecule were performed to study the role of temperature, surface structure and electrochemical environment for the oxidation of 2-propanol to acetone at the Co₃O₄ (001)/H₂O interface on the A-terminated and B-terminated surfaces. In both cases, no C-H bond cleavage is observed at room temperature. However, under oxidative conditions, which are modeled here by partial dehydrogenation of the mixed hydroxyl/water adsorbate layer, dehydrogenation of the alcoholic OH group is observed on both surface terminations. As a result, adsorbed 2-propanolate is formed. The reaction on the less hydroxylated B- terminated surface further proceeds with C-H bond cleavage at the 2-carbon atom. The oxidation product acetone remains adsorbed on the Co³⁺ site during the simulation period of approximately 20 ps. Both deprotonation steps are aided by the presence of the adsorbed hydroxyl groups in the vicinity of the adsorbed alcohol molecule, because both hydrogen atoms from the reac- tand molecule are transferred as protons to form adsorbed water molecules. Different from the case of the partially dehydrogenated environment, raising the system temperature from 300 to 450 K, which can be considered a simple model for high temperature thermal catalysis, does not lead to oxidation via C-H dehydrogenation of the 2-propanol molecule.