Electrolysis

Gamry Instruments has a large variety of potentiostats/galvanostats for the testing of electrolyzers. All of our potentiostats/galvanostats are capable of performing electrochemical impedance spectroscopy, a very well known technique for analyzing systems during operation. Additionally, all of our potentiostats/galvanostats are isolated from Earth ground, making measurements on grounded cells (like electrolyzers!) very easy.

Our standard lineup includes instruments capable of outputting 600 mA, 1 A, 3 A, and 5 A. Reference 3000 combined with the Reference 30k Booster then lets you apply and measure up to +/-30 A of current at +20/-2.5 V. Finally, if 30 A is not enough, the LPI1010 Load/Power Supply Interface allows us to expand to even higher currents when necessary. Our LPI1010 combines the signal generation and accurate measuring capabilities of an Interface 1010E with an electronic load (or power supply) to work at higher currents (>30A).

Have more than one cell operating? Gamry makes testing of these systems easy too! Our Reference 3000 with Auxiliary Electrometer gives you an additional eight measurement channels for measuring each individual cell in a stack (up to eight). So now you can measure up to eight cells simultaneously in a single experiment.

Electrolysis is a process that involves the use of a potentiostat or galvanostat to push electrical current through an electrochemical cell to drive a non-spontaneous electrochemical reaction. The electrochemical cell contains an electrolyte (i.e. solvent that with ions) that participates in the electrochemical reaction. One or more of these components may undergo electrolysis.

Electrolysis can involve two or three electrodes. The two-electrode process involves an anode and a cathode, where oxidation and reduction take place, respectively. While simpler in principle, the two-electrode setup sacrifices accuracy and control. A three-electrode process involves an anode, cathode, and reference electrode. The addition of a reference electrode allows for an accurate determination of the working electrode potential, thus giving more control over the process.
The production of hydrogen gas (H2) from water is a very good example of electrolysis. In the overall reaction, two molecules of water produce two molecules of H2 and one molecule of O2 as show below:

2 H₂O(l) → 2 H₂(g) + O₂(g)

Remember, this is the overall reaction though. Individually, there are half-reactions occurring at the anode and cathode. These are:

Anode: 2 H₂O(l) → O₂(g) + 4 H+(aq) + 4 e-
Cathode: 4 H₂O(l) + 4 e- → 2 H₂(g) + 4 OH-(aq)

As the world moves to add alternative sources of energy, hydrogen can play an important role in a more sustainable energy economy. Another method to produce hydrogen can come from the electrolysis of ammonia.

Ammonia electrolysis works by splitting ammonia (NH₃) into H₂ and nitrogen gas (N2). The overall reaction can be written as:

2 NH_¬3(l)→ 3 H₂(g) + N₂(g)

Ammonia is a low-cost and readily available feedstock, making ammonia electrolysis a viable, low-cost method for transport and production of hydrogen. Finally, this process can also be powered by renewable energy sources such as solar or wind power.

One final example of an electrolytic process that isn’t as commercially viable as of yet but could have an incredibly large impact on reducing greenhouse gas emissions is the electrolysis of carbon dioxide (CO₂). New catalyst materials are being developed to improve the selectivity and activity of the electrode reactions, while novel reactor designs and operating conditions are being explored to enhance the performance and durability of the electrolysis cells. While the practical applications of CO₂ electrolysis are still in the early stages of development, it has the potential to play an important role in the transition to a more sustainable energy economy.

Many Gamry systems can meet the needs of a fuel cell researcher. The Interface 1010E, with currents up to 1 A, is a great system for studying materials or smaller setups.  The Interface 5000E is a great single cell system that can provide up to 5A @ 6 V.  The Interface 5000E can also measure both half cells simultaneously in a three-electrode system. Our Reference 3000/3000AE along with the Reference 30K Booster for extra current is an ideal solution for fuel cells that operate up to 30 A total current, and up to 20 V in the stack.  It is capable of running both DC and AC testing. Both the Interface line and Reference line of instruments can be configured into bipotentiostat setups for running RRDE experiments.  

The LPI1010 (combined with an Interface 1010E) lets you go to even higher currents for measuring large electrolysis cells. We have several different electronic load and power supply manufacturers who can interface with our LPI1010. Give us a call to find out more.