Molecular Beam Epitaxially Grown Catalysts for FY25 Blue Carbon–Direct Air Capture Program

Author(s):

David R. Baker, Vijay S. Parameshwaran, and Caroline M. Hill

Abstract:

The selectivity of products from the carbon dioxide reduction reaction (CO2RR) is highly diverse because of similar reaction potentials for a variety of products. Crystal facets of electrocatalysts have had implied impact on CO2RR selectivity but definitive causation is hampered by the heterogeneous surface states inherent to nanoparticle geometries. Molecular beam epitaxy (MBE) allows for copper (Cu) electrocatalyst growth to be controlled in a single-crystal format. This effort explores multiple crystal orientations of Cu and Cu alloys grown as single-crystal films with MBE and monitoring the reaction products. Substrates are single-crystal silicon wafers to aid in controlling the growth direction and were sent to a partner for CO2RR product analysis in an H-cell configuration. Additionally, the same deposition recipes are used to grow on fibrous gas diffusion electrodes and are tested in a zero-gap cell to explore initial scale-up effects, specifically tracking the production of ethylene.