Setting up gold, silver, or platinum substrates for cyclic voltammetry and EC-STM: contacting, cleaning, electrochemical window, and where each metal falls short.
A working electrode is only as good as its surface. Trace contamination, an uneven metal layer, or the wrong choice of metal for your redox couple shows up directly in your voltammogram, whether that's a shifted peak, a sloped baseline, or a response that won't reproduce between runs. arrandee™ substrates are deposited without an adhesion layer between the metal and the working surface where possible. What you contact and measure is the metal itself, not a buried interface.
How to physically contact a substrate in a cell, what electrochemical window to expect from each of the three metals, how to clean or pretreat before a run, and the handful of mistakes behind most of the "my CV looks wrong" questions we get asked. We assume you already know your electrochemistry; this guide is about the substrate, not the technique.
What to expect before you even start cycling
| Property | Gold (Au) | Silver (Ag) | Platinum (Pt) |
|---|---|---|---|
| Usable window in aqueous electrolyte | Wide, well documented | Narrow, limited by early oxide formation | Widest, especially cathodic side |
| Standard pretreatment | Flame annealing or CV cycling in blank electrolyte | Electrochemical or mild chemical cleaning only | Flame annealing or CV cycling in blank electrolyte |
| Typical role | General-purpose working electrode, SAM studies | Rarely used as a working electrode; mainly plasmonic (SERS/SPR) | Catalysis (ORR, HER), reference/counter |
| Surface oxide behavior | Minimal at moderate potentials | Forms readily, which limits reproducibility | Forms reversibly, used diagnostically (CV "fingerprint") |
| Reuse after cleaning | Good, standard practice | Limited; surface degrades faster | Good, standard practice |
Contacting, geometry, and the mistakes that cost people a week
A quick cross-reference before you order
The default choice for general electrochemistry, SAM-modified electrodes, and studies that need a wide, stable window without platinum's catalytic activity getting in the way.
View Gold SubstratesNot a typical CV working electrode. Its value here is as a plasmonic substrate for SERS-coupled electrochemistry, where the electrochemical signal takes a back seat to the optical enhancement.
View Silver SubstratesThe standard for catalysis-related work such as ORR and HER, where the electrode's own catalytic activity is part of the experiment rather than something to avoid.
View Platinum SubstratesSetup questions we get asked most often
Most groups use a spring-loaded contact clip or a small alligator clip on the exposed metal edge. A custom PTFE cell that presses the sample against an O-ring and contacts the back of the metal layer directly works too. Because the gold, silver, and platinum layers are deposited without an insulating layer on top, any clean metal-to-metal contact point on the coated surface will do the job, provided it stays outside the area you're measuring.
Gold and platinum both give you a wide, well-documented window in aqueous electrolyte; platinum usually extends a bit further on the hydrogen evolution side. Silver is more limited. It oxidizes at less positive potentials, and that narrower window is the main reason it rarely shows up as a working electrode outside plasmonic or specialty applications.
Yes. For gold and platinum, flame annealing or a brief electrochemical cleaning cycle (repeated potential cycling in blank electrolyte) is standard practice for removing adsorbed contaminants before a measurement. Silver is different: its low melting point rules out flame annealing, so labs clean it electrochemically or with a mild chemical treatment instead.
Yes, within limits. Most labs routinely re-anneal and reuse gold and platinum substrates without issue. Check surface quality periodically, for example by running cyclic voltammetry in blank electrolyte and looking for the expected characteristic peaks, and replace the substrate once the response degrades.