High-Purity Gold Electrodes from Advent Advance Battery and CO2 Conversion Research
Researchers at the University of Liverpool have made significant progress in understanding what happens at electrode surfaces during electrochemical reactions—work that could lead to better batteries, more efficient CO₂ converters, and improved fuel cells.
The study, published in Faraday Discussions, used high-purity gold materials supplied by Advent Research Materials to create specialised thin-film electrodes that revealed hidden molecular behaviour at electrified interfaces.
Science Made Simple
When developing batteries or systems that convert CO2 into useful chemicals, scientists face a challenge: they can't easily see what's happening at the exact point where the electrode meets the liquid electrolyte. This interface—just a few nanometers thick—controls how well the device works, but it's been difficult to observe directly.
Think of it like trying to understand a busy intersection by only measuring traffic flow before and after—you know cars are getting through, but you don't know if they're queuing, switching lanes, or taking shortcuts.
The Liverpool team used a specialised laser technique called Vibrational Sum Frequency Generation (VSFG) spectroscopy to "watch" individual molecules at this critical interface. They discovered that adding tiny amounts of water or other additives dramatically reorganizes how solvent molecules arrange themselves at the electrode surface—like adding a traffic officer to that intersection completely changes driving patterns.
This matters because the arrangement of these molecules determines which chemical reactions happen, how efficiently they occur, and whether you get the products you want or unwanted side reactions.
The Technical Challenge
Electrochemical devices rely on precise control of the electric double layer (EDL)—the region where charged electrode surfaces interact with ions and molecules in solution. In non-aqueous solvents like acetonitrile, commonly used in lithium batteries and CO2 reduction systems, this structure is poorly understood.
The research team needed to probe this interface under working conditions—with voltage applied and chemical reactions occurring—without disrupting the very phenomena they were studying. Traditional spectroscopic methods struggle at buried solid-liquid interfaces, where signal from bulk solution overwhelms the interface signal.
Advent's Role: Precision Gold for Advanced Spectroscopy
The breakthrough relied on ultra-thin gold electrodes manufactured using 99.95% purity gold from Advent Research Materials. The research team specified Advent gold for two critical components:
1. Thin-Film Working Electrodes Gold from Advent was thermally deposited onto calcium fluoride windows to create ~25 nanometer thick electrodes. This precise thickness is essential—thick enough to conduct electricity and create a proper electrochemical interface, but thin enough to allow infrared laser light to pass through for "backside" spectroscopic measurements.
2. Counter Electrodes High-purity 0.5 mm diameter Advent gold wire served as the counter electrode, completing the electrochemical circuit. The purity specification ensures minimal contamination that could interfere with sensitive surface measurements.
Why Material Purity Matters
In surface-sensitive spectroscopy, trace impurities can dominate signals and produce misleading results. The researchers were detecting molecular vibrations from species present at sub-monolayer coverage—essentially reading chemical signatures from just a few layers of molecules.
Advent's 99.95% gold specification ensures that the electrode surface chemistry is controlled and reproducible. Any contaminants at the gold surface could:
- Alter how solvent molecules arrange themselves
- Introduce spurious spectroscopic signals
- Change the local electric field distribution
- Affect electron transfer kinetics
The team's computational models, validated against their experimental data, confirmed that van der Waals interactions between gold and solvent molecules play a major role in determining interfacial structure—interactions that would be disrupted by surface contamination.
Key Findings With Industrial Relevance
Using their Advent gold electrode system, the Liverpool researchers discovered:
Water content critically affects interface structure: At just 300 ppm water (typical for "dry" acetonitrile), the interface showed weak molecular ordering. Increasing to 2,100 ppm created structured interfacial layers through hydrogen bonding. At 24,000 ppm, highly ordered acetonitrile layers formed further from the electrode surface.
Additives accumulate preferentially: N-methyl-2-pyrrolidone (NMP), an additive known to improve CO₂ reduction performance, accumulated at negatively charged gold surfaces under dry conditions. However, adding water displaced NMP and reorganized the entire interfacial structure.
Tuning electric fields: The team measured how strongly the local electric field changed with applied voltage by tracking cyanide vibrations (from acetonitrile breakdown products). Systems with higher water content showed 2-3× stronger field gradients, explaining why small amounts of water improve reaction rates.
Potential Applications in Energy and Sustainability
This fundamental understanding has direct implications for:
- Lithium battery electrolytes: Controlling interfacial water content could reduce unwanted side reactions that degrade battery performance over repeated charging cycles.
- CO2 electrochemical reduction: Understanding how additives like NMP modify the electrode interface explains why certain electrolyte formulations dramatically improve selectivity for producing valuable chemicals versus unwanted hydrogen gas.
- Electrochemical synthesis: Pharmaceutical and specialty chemical manufacturers could design non-aqueous electrolytes with predictable interfacial structures to improve selectivity in complex synthesis reactions.
Looking Forward: Materials for Next-Generation Electrochemistry
The Liverpool team's methodology—combining thin-film gold electrodes with advanced spectroscopy and computational modeling—creates a roadmap for rational electrolyte design.
Rather than trial-and-error screening of additives, researchers can now predict and verify how specific molecules will organise at electrode surfaces.
Advent Research Materials continues to supply high-purity metals for electrochemistry research across academic and industrial laboratories.s
The availability of consistent, certified gold materials enables researchers to focus on electrochemical phenomena rather than worrying about material variability between experiments.
Research Details
Publication: Hill, N.J.D., O'Brien, C., Donaldson, P.M., et al. "Unravelling the role of additives in the structure of non-aqueous media at the electrode surface under potential control." Faraday Discussions, 2026. DOI: 10.1039/D5FD00118H
Institution: University of Liverpool Stephenson Institute for Renewable Energy; STFC Rutherford Appleton Laboratory
About Advent Research Materials
Advent Research Materials supplies high-purity metals, alloys, and compounds to research institutions and industrial R&D laboratories worldwide. Our ISO 9001 certified quality systems ensure consistent material specifications for demanding applications in electrochemistry, materials science, and advanced characterisation techniques.
Need high-purity gold for electrochemical research? Contact our team to discuss your electrode material requirements: info@advent-rm.com | +44 1865 884 440