Speakers
Description
Carbon capture and reutilization is a necessity for transitioning towards a sustainable society. Electrocatalytic carbon dioxide reduction reactions (CO2RR) to hydrocarbons at copper cathodes is one promising route, where the selectivity and activity are dictated by a complex interplay of copper oxidation state, structure, and oxygen content at the (sub)surface.[1] Stabilization of these catalytically active species and tuning of the surface microenvironment is critical for catalyst longevity, selectivity, and to improve mechanistic insights. For instance, copper nanoparticles modified with silica thin films have shown increased ethylene production attributed to suppression of hydrogen evolution and stabilization of key CO2RR intermediates.[2] This work demonstrates the use of a crystalline two-dimensional silica network grown under ultra-high vacuum (UHV) conditions to encapsulate pre-oxidized Cu(111) single crystal surfaces, a proposed catalytically active surface motif for CO2RR, and alter CO2RR reactivity.[3] The silica network stabilizes the surface mesoscopic structure and chemical composition for long-term and repeated CO2RR operations relative to unmodified Cu(111) single crystals based on ex situ analyses.[4] In turn, the passivation and formation of nanoconfined reactive sites by the silica network alters the product distribution relative to pristine Cu(111). Our findings demonstrate the ability to modify operation of a model CO2RR electrocatalyst by a two-dimensional overlayer, where further in situ and in operando measurements will help elucidate the dynamics of the surface during CO2RR.
1. Yu, J., Wang, J., Fan, Z. et al. Recent Progresses in Electrochemical Carbon Dioxide Reduction on Copper-Based Catalysts toward Multicarbon Products. Adv. Fun. Mater. 31, 2102151 (2021).
2. Li, J., Sargent, E.H., Sinton, D. et al. Silica-copper catalyst interfaces enable carbon-carbon coupling towards ethylene electrosynthesis Nat. Commun. 12, 2808 (2021).
3. Navarro, J.J., Tosoni, S., Roldan Cuenya, B. et al. Structure of a Silica Thin Film on Oxidized Cu(111): Conservation of the Honeycomb Lattice and Role of the Interlayer. J. Phys. Chem. C 124, 20942-20949 (2020).
4. Nguyen, K.C., Bruce, J.P., Roldan Cuenya, B., et al. The Influence of Mesoscopic Surface Structure on the Electrocatalytic Selectivity of CO2 Reduction with UHV-Prepared Cu(111) Single Crystals. ACS Energy Lett. 9, 644-652 (2024).
