Electrochemical Surface Area Quantification, CO2 Reduction Performance, and Stability Studies of Unsupported Three-Dimensional Au Aerogels versus Carbon-Supported Au Nanoparticles
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Contributors
Abstract
The efficient scale-up of CO2-reduction technologies is a pivotal step to facilitate intermittent energy storage and for closing the carbon cycle. However, there is a need to minimize the occurrence of undesirable side reactions like H2 evolution and achieve selective production of value-added CO2-reduction products (CO and HCOO−) at as-high-as-possible current densities. Employing novel electrocatalysts such as unsupported metal aerogels, which possess a highly porous three-dimensional nanostructure, offers a plausible approach to realize this. In this study, we first quantify the electrochemical surface area of an Au aerogel (≈5 nm in web thickness) using the surface oxide-reduction and copper underpotential deposition methods. Subsequently, the aerogel is tested for its CO2-reduction performance in an in-house developed, two-compartment electrochemical cell. For comparison purposes, similar measurements are also performed on polycrystalline Au and a commercial catalyst consisting of Au nanoparticles supported on carbon black (Au/C). The Au aerogel exhibits a faradaic efficiency of ≈97% for CO production at ≈−0.48 VRHE, with a suppression of H2 production compared to Au/C that we ascribe to its larger Au-particle size. Finally, identical-location transmission electron microscopy of both nanomaterials before and after CO2-reduction reveals that, unlike Au/C, the aerogel network retains its nanoarchitecture at the potential of peak CO production.
Details
Original language | English |
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Pages (from-to) | 278-292 |
Number of pages | 15 |
Journal | ACS Materials Au |
Volume | 2 |
Issue number | 3 |
Publication status | Published - 11 May 2022 |
Peer-reviewed | Yes |
Keywords
ASJC Scopus subject areas
Keywords
- copper underpotential deposition, electrocatalyst, hydrogen evolution reaction, identical-location transmission electron microscopy, particle size effect