I have done LSV for my Fe and Co based complexes in 1M KOH solution and by using Ag/AgCl reference electrode. Many people say calomel or Hg/HgO electrode should be used. But only Ag/AgCl is available in our lab. How to justify that Ag/AgCl can be used for hydrogen evolution studies in KOH solution?
Hello Madhumitha Rajakumar
I would suggest Hg/HgO (mercury / mercurous oxide) if possible, otherwise SCE should be OK for short periods.
An alternative is to use a salt bridge. The frits may start to clog, so it would need regular inspection and/or cleaning. Also, always try and rinse the electrodes in water as quickly as possible once the test is finished.
Best regards,
Marie B.
As Marie Berthuel points out, a Hg/HgO reference electrode (RE) is the best option.
The problem you have is that KOH will also slowly etch the glass.
Regardless of what you decide to do, it is always good practice to isolate a separate RE that is not subjected to experiments in order to compare other REs with. You can easily check the condition of a "used" RE by placing it in an electrolyte solution with the "new" RE and measuring the potential with a voltmeter. Ideally the difference should be just a few mV.
Jules
2Ag+ + NaOH = Ag2O (precipitate) + 2Na+ + H2O
The precipitate of Ag2O will clog the frit.
Use a salt bridge, as Marie Berthuel said.
Thank you for all your suggestions. I will work it out with other electrodes as you said.
I faced the same problem working in alkaline redox flow battery in which my electrolyte is 1M KOH. Long terms experiment are not suitable with Ag/AgCl reference electrodes since the frit get dissolved by the KOH solution.
I am now using Hg/HgO (1M NaOH) that I purchased from Bio-Logic for 300 euros. Depending your catalyts concentration, you might add a double glass junction to the Hg/HgO reference electrode in order to avoid contamination.
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