Electrochemical Surface Area Quantification, CO2 Reduction Performance, and Stability Studies of Unsupported Three-Dimensional Au Aerogels versus Carbon-Supported Au Nanoparticles

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Piyush Chauhan - , Paul Scherrer Institute (Author)
  • Karl Hiekel - , Chair of Physical Chemistry, TUD Dresden University of Technology (Author)
  • Justus S. Diercks - , Paul Scherrer Institute (Author)
  • Juan Herranz - , Paul Scherrer Institute (Author)
  • Viktoriia A. Saveleva - , Paul Scherrer Institute (Author)
  • Pavel Khavlyuk - , Chair of Physical Chemistry, TUD Dresden University of Technology (Author)
  • Alexander Eychmüller - , Chair of Physical Chemistry, TUD Dresden University of Technology (Author)
  • Thomas J. Schmidt - , Paul Scherrer Institute, ETH Zurich (Author)

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 languageEnglish
Pages (from-to)278-292
Number of pages15
JournalACS Materials Au
Volume2
Issue number3
Publication statusPublished - 11 May 2022
Peer-reviewedYes

Keywords

Keywords

  • copper underpotential deposition, electrocatalyst, hydrogen evolution reaction, identical-location transmission electron microscopy, particle size effect