title: Tailoring Copper Nanocrystals towards C2 Products in Electrochemical CO2 Reduction.
abstract: Favoring the CO2 reduction reaction (CO2RR) over the hydrogen evolution reaction and controlling the selectivity towards multicarbon products are currently major scientific challenges in sustainable energy research. It is known that the morphology of the catalyst can modulate catalytic activity and selectivity, yet this remains a relatively underexplored area in electrochemical CO2 reduction. Here, we exploit the material tunability afforded by colloidal chemistry to establish unambiguous structure/property relations between Cu nanocrystals and their behavior as electrocatalysts for CO2 reduction. Our study reveals a non-monotonic size-dependence of the selectivity in cube-shaped copper nanocrystals. Among 24 nm, 44 nm and 63 nm cubes tested, the cubes with 44 nm edge length exhibited the highest selectivity towards CO2RR (80 %) and faradaic efficiency for ethylene (41 %). Statistical analysis of the surface atom density suggests the key role played by edge sites in CO2RR.
authors.affiliation: Department of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, 1950, Sion, Switzerland.
authors.forename: Anna
authors.initials: A
authors.lastname: Loiudice
authors.affiliation: Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.|Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Lobaccaro
authors.affiliation: Department of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, 1950, Sion, Switzerland.
authors.forename: Esmail A
authors.initials: EA
authors.lastname: Kamali
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
authors.forename: Timothy
authors.initials: T
authors.lastname: Thao
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA, 94720, USA.
authors.forename: Brandon H
authors.initials: BH
authors.lastname: Huang
authors.affiliation: Joint Center for Artificial Photosynthesis, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.|Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA.
authors.forename: Joel W
authors.initials: JW
authors.lastname: Ager
authors.affiliation: Department of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, 1950, Sion, Switzerland. raffaella.buonsanti@epfl.ch.
authors.forename: Raffaella
authors.identifier: 0000-0002-6592-1869
authors.initials: R
authors.lastname: Buonsanti
keywords: colloidal chemistry; electrochemical CO2 reduction; nanocrystals; nanocubes; selectivity