Adsorption of Ethanol and Intermediates on Co(0001): A DFT-Based Investigation

This work aims to investigate the adsorption of ethanol and its key intermediates such as ethoxy, acetaldehyde, CH₃CO, CH₂ and CH₃, on the metallic cobalt surface Co(0001) using Quantum Density Functional Theory (q-DFT) for the etanol steam reforming. The study focuses on how different adsorption geometries and bonding configurations influence the stability and reactivity of surface species relevant to this reaction. By modeling ethanol, ethoxy, and CH_x fragments on various adsorption sites (top, bridge, hcp, and fcc), the project seeks to identify preferred binding modes and assess their impact on the initial steps of ethanol decomposition. Although detailed numerical results are still in progress, this research establishes the computational framework and methodology necessary to quantify adsorption energies and reaction pathways in future work. Initial q-DFT calculations were performed using the VASP code with the GGA-PBE functional and PAW pseudopotentials. Adsorption tests were carried out for ethanol, ethoxy, CO, CO₂, and CH_x fragments on the top, bridge, hcp, and fcc sites. The preliminary adsorption energies indicate stronger interactions for fragments compared to molecular ethanol, particularly for ethoxy and CHₓ species, confirming the expected stabilization upon dehydrogenation. Challenges were encountered during surface construction, relaxation, and sensitivity of adsorption energy to vacuum size and initial configuration. Our ongoing work plan is to refine the adsorption geometries, apply dispersion corrections (DFT-D3), and employ the NEB method to determine transition states and energy barriers. The goal is to build a complete reaction pathway for ethanol decomposition on Co(0001) and evaluate how adsorption mode influences catalytic selectivity toward CO, CO₂, CH₄, or H₂ formation.