Work

Assessing the Correct Electrochemical Surface Area of Gold Electrocatalysts by Copper Underpotential Deposition

Year: 2026

Type: article

Abstract: Knowing the electrochemical surface area (ECSA) is crucial to fully understand an electrocatalytic system and correctly contextualize the behavior of a catalyst. We show that the surface oxidation method poses several problems for the ECSA determination, while the copper underpotential deposition method (Cu-UPD) allows reproducible and non-destructive determination of the ECSA of gold-based catalysts. To quantify the copper underpotential deposition charge, we combine single-crystalline Au(111) and Au(110) gold samples with surface-sensitive scanning tunneling microscopy and X-ray photoelectron spectroscopy characterization, providing a precise and independent calibration procedure to link the oxidation of one deposited Cu atom in Cl–-containing electrolyte to a passed charge of 1.01 ± 0.04 electrons per Cu atom for Au(111) and 0.98 ± 0.15 e–/Cu for Au(110). Relating to the gold surface area, the copper oxidation charges amount to 137 ± 6 μC/cmAu(111)2 and 134 ± 20 μC/cmAu(110)2. Reliable results are obtained by using an electrochemical cell that allows for air-free transfer to and from the vacuum-based preparation and characterization methods. Due to the low applied potentials, the Cu-UPD method does not alter the structure of the original gold surface itself.

Source: ACS electrochemistry.

DOI: 10.1021/acselectrochem.6c00053

Authors: Paul M. Leidinger, Jeppe V. Lauritsen

Institution: Aarhus University

Language: English

Topic: Electrocatalysts for Energy Conversion

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

Open Access status: green

Funders: Deutsche Forschungsgemeinschaft, Danmarks Grundforskningsfond

Award: G1307354898