Working Paper
Authors
- Karla Banjac
Ecole Polytechnique Fédérale de Lausanne (EPFL) ,
- Thanh Hai Phan École Polytechnique Fédérale de Lausanne ,
- Fernando P. Cometto École Polytechnique Fédérale de Lausanne ,
- Patrick Alexa ,
- Yunchang Liang École Polytechnique Fédérale de Lausanne ,
- Rico Gutzler Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg ,
- Magalí Lingenfelder École Polytechnique Fédérale de Lausanne
Abstract
The electrochemical reduction of CO2 (CO2RR) into multicarbon compounds is a promising pathway towards renewable chemicals. Structure-product selectivity studies highlight that copper (100) facets favour C2+ product formation. However, the atomic processes leading to the formation of (100)-rich Cu cubes remains elusive. Herein, we use Cu and graphene-protected Cu surfaces to reveal the differences in structure and composition of common Cu-based electrocatalysts, from nano to micrometer scales. We show that stripping/electrodeposition cycles lead to thermodynamically controlled growth of Cu2O micro/nanocubes, while multi-layered Cu nanocuboids form universally during CO2RR upon polarization-driven re-organization of Cu0 atoms. A synergy of electrochemical
characterization by scanning tunnelling microscopy (EC-STM), operando EC-Raman and quasi-operando X-Ray Photoemission spectroscopy (XPS) allows us to shed light on the role of oxygen on the dynamic interfacial processes of Cu, and to demonstrate that chloride is not needed for the stabilization of cubic Cu nanostructures.
Content

Supplementary material

Operando surface chemistry of micro- and nanocubic copper catalysts for electrochemical CO2 reduction: SI
Supplementary Information: additional SEM, AFM, and STM images, Raman and XPS data, methods.