TY - JOUR
T1 - Multi-spectroscopic study of electrochemically-formed oxide-derived gold electrodes
AU - Bibi, Sara Boscolo
AU - El-Zohry, Ahmed M.
AU - Davies, Bernadette
AU - Grigorev, Vladimir
AU - Goodwin, Christopher M.
AU - Lömker, Patrick
AU - Holm, Alexander
AU - Ali-Löytty, Harri
AU - Garcia-Martinez, Fernando
AU - Schlueter, Christoph
AU - Soldemo, Markus
AU - Koroidov, Sergey
AU - Hansson, Tony
N1 - Publisher Copyright:
© 2024 The Royal Society of Chemistry.
PY - 2023/12/12
Y1 - 2023/12/12
N2 - Oxide-derived metals are produced by reducing an oxide precursor. These materials, including gold, have shown improved catalytic performance over many native metals. The origin of this improvement for gold is not yet understood. In this study, operando non-resonant sum frequency generation (SFG) and ex situ high-pressure X-ray photoelectron spectroscopy (HP-XPS) have been employed to investigate electrochemically-formed oxide-derived gold (OD-Au) from polycrystalline gold surfaces. A range of different oxidizing conditions were used to form OD-Au in acidic aqueous medium (H3PO4, pH = 1). Our electrochemical data after OD-Au is generated suggest that the surface is metallic gold, however SFG signal variations indicate the presence of subsurface gold oxide remnants between the metallic gold surface layer and bulk gold. The HP-XPS results suggest that this subsurface gold oxide could be in the form of Au2O3 or Au(OH)3. Furthermore, the SFG measurements show that with reducing electrochemical treatments the original gold metallic state can be restored, meaning the subsurface gold oxide is released. This work demonstrates that remnants of gold oxide persist beneath the topmost gold layer when the OD-Au is created, potentially facilitating the understanding of the improved catalytic properties of OD-Au.
AB - Oxide-derived metals are produced by reducing an oxide precursor. These materials, including gold, have shown improved catalytic performance over many native metals. The origin of this improvement for gold is not yet understood. In this study, operando non-resonant sum frequency generation (SFG) and ex situ high-pressure X-ray photoelectron spectroscopy (HP-XPS) have been employed to investigate electrochemically-formed oxide-derived gold (OD-Au) from polycrystalline gold surfaces. A range of different oxidizing conditions were used to form OD-Au in acidic aqueous medium (H3PO4, pH = 1). Our electrochemical data after OD-Au is generated suggest that the surface is metallic gold, however SFG signal variations indicate the presence of subsurface gold oxide remnants between the metallic gold surface layer and bulk gold. The HP-XPS results suggest that this subsurface gold oxide could be in the form of Au2O3 or Au(OH)3. Furthermore, the SFG measurements show that with reducing electrochemical treatments the original gold metallic state can be restored, meaning the subsurface gold oxide is released. This work demonstrates that remnants of gold oxide persist beneath the topmost gold layer when the OD-Au is created, potentially facilitating the understanding of the improved catalytic properties of OD-Au.
UR - https://www.scopus.com/pages/publications/85181438734
U2 - 10.1039/d3cp04009g
DO - 10.1039/d3cp04009g
M3 - Article
AN - SCOPUS:85181438734
SN - 1463-9076
VL - 26
SP - 2332
EP - 2340
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
IS - 3
ER -