April 22 - 26, 2024
Seattle, Washington
May 7 - 9, 2024 (Virtual)
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2024 MRS Spring Meeting & Exhibit
EN09.05.10

Bimetallic Interface Control of Cu2O Nanocrystals for Efficient CO2-to-C2+ Chemical Conversion

When and Where

Apr 24, 2024
11:30am - 11:45am
Room 337, Level 3, Summit

Presenter(s)

Co-Author(s)

Seolha Lim1,Woosuck Kwon1,Dae-Hyun Nam1

Daegu Gyeongbuk Institute of Science and Technology1

Abstract

Seolha Lim1,Woosuck Kwon1,Dae-Hyun Nam1

Daegu Gyeongbuk Institute of Science and Technology1
Electrochemical carbon dioxide reduction reaction (CO2RR) is promising in the pursuit of carbon neutrality, as it converts CO2, the primary contributor to global warming, into valuable high-end fuels and chemical feedstocks. Copper (Cu) is the only metal that has an appropriate *CO binding energy for C-C coupling. Cu-based CO2RR electrocatalysts can produce multi-carbon (C2+) chemicals such as ethylene, ethanol, and acetic acid. Nonetheless, they suffer from low selectivity for producing specific products. Particularly, bimetallic systems including Cu with secondary metals such as Au and Ag for their weak *CO bonds, emerge as a promising strategy to enhance the production of C2+ chemicals. However, the focus of Cu-based bimetallic catalysts has primarily been optimizing the ratio of secondary metals, overlooking the significance of interface control for efficient CO2RR.
In this study, we fabricated the facet-controlled Cu2O nanocrystals (NCs) and studied the effect of bimetallic interface design on the CO2RR. Cu2O NCs includes cube with (100) facets, cuboctahedron (cubo) with (100) and (111) facets, and octahedron (octa) with (111) facets. We introduced Ag and Au as secondary metals to facet controlled Cu2O NCs through galvanic replacement. Shape and size distributions of the secondary metal were affected by surface energy and the surface atomic diffusion rate. These factors proved to be pivotal in the fabrication of three distinct catalysts, each characterized by varying Cu-Ag, Cu-Au interfacial compositions. In general, Cu2O cube with low-surface-energy exhibited segregation and agglomeration at the interfaces, whereas Cu2O cubo and octa with high-surface-energy formed well-dispersed interfaces. Bare Cu2O cube exhibited a 40% Faradaic efficiency (FE) for C2+ products and achieved H2 FE of 19% at -0.73 V (vs RHE). Ag-augmented Cu2O cube significantly improved selectivity by reaching 57% FE for C2+ and suppressing H2 with a FE of 13% at -0.78 V (vs RHE). In contrast, the Au-augmented Cu2O cube promoted H2 with 25% FE and C2+ with 33% FE at -0.99 V (vs RHE), resulting in reduced performance. To gain deeper insights into the intermediate behavior of *CO, in-situ Raman spectroscopy was employed, highlighting the critical importance of the metal effect in CO2RR. Remarkably, it was observed that CO derived from Ag had a more pronounced impact on increasing *CO coverage on the Cu surface compared to that of Au. Furthermore, the relatively higher portion of high-frequency band (HFB) *COatop represents efficient C-C coupling. This study sheds light on the bimetallic interface design of Cu-based active sites for efficient C2+ chemical production in CO2RR.

Keywords

morphology | surface reaction

Symposium Organizers

Christopher Barile, University of Nevada, Reno
Nathalie Herlin-Boime, CEA Saclay
Michel Trudeau, Concordia University
Edmund Chun Ming Tse, University Hong Kong

Session Chairs

Michel Trudeau
Edmund Chun Ming Tse

In this Session