I believe the reasoning for this change from Pt to GC was based on the cathodic reactions taking place in your system. In a standard system, this would be hydrogen evolution (for which Pt is indeed better). The (additional) reactions taking place in your particular system may be made more desirable by the use of GC instead of Pt, but without the full details of your experimental system (and catalysts, which are likely confidential know how at this point) I cannot offer a more confident answer.

The following two works (although focusing on the use of solar energy) include some discussion of cathodic processes in OER:

A. J. Bard, M. A. Fox, Acc. Chem. Res. 1995, 28, 141.

N. S. Lewis, D. G. Nocera, Proc. Natl. Acad. Sci. 2006, 103, 15729

Hi Renjie Wei,

I agree with Tomasz Jarosz. In fact, the use of Pt as CE is better than that of GC because Pt, as you know, is a noble metal and therefore has a large stability range even if you sweep the potential to very negative values.

Yes, you are right. When we are operating OER using Pt as counter electrode, the Pt wire will not dissolve. Because during OER process, the CE (Pt wire) is cathode, and the reaction on the surface of Pt is HER. Pt will not dissolve at this potential, and thus will not be deposited on WE again.

Actually, it is better to use Pt rather than graphite rod as CE during OER process. Here is a reference which I believe can answer the reviewer's question.

Measurement Techniques for the Study of Thin Film Heterogeneous

Water Oxidation Electrocatalysts. Chem. Mater. 2017, 29, 120−140

DOI: 10.1021/acs.chemmater.6b02796

Good luck.

Dear Wei,

I fully agree with what you said - when HER is supposed to be the counter reaction, nothing beats Pt in terms of activity and stability. Carbon based materials are extremely unstable for anodic reactions because they will generate large amounts of CO2 and perhaps water-soluble oxygenated carbon species, but they are probably okay to use cathodically as counter electrode. Still I see no reason why one would choose a carbon electrode over Pt in this case, besides cost considerations.

There is a very, very minor risk of cathodic corrosion under negative potentials when using Pt (see DOI: 10.1038/ncomms12653) - however this will only happen in strong base at extreme overpotentials (>0.4 V) relative to HER. As long as your Pt counter has a high enough surface area you'll never reach this. Above all, cathodic corrosion should not generate water soluble species, only insoluble Pt nanoparticles.

Thanks Jan Vos to your answer.

May be the reason to replace Carbon for Pt is that you might get better range of voltage with respect to the reference electrode. I think the manufacturer of the carbon electrode made sure that the their carbon electrode is stable in both alkaline and acidic range.

For anodic OER

2H2O ⟶ 4e− + 4H+ + O2

HER will be at the counter electrode. both electrode can be used.

Dear Renjie Wei,

that proposal (for carbon rod instead Pt as CE, in OER process) was for a set of 2 (or 3) electrodes cell's configuration ?

Also, what is the (hypothetical) argument(s) behind that proposition ?

Sorry for my late reply, all. I am outside these days and did not take my PC and as well as cannot access the database. Thx a lot for your answers, in my experience, three-electrodes setup, WE is Co3O4 (OER catalysts), CE is Pt wire, RE is SCE. Later, I will read your recommended papers and reply you. I still believe that for HER catalysts test, should use Carbon rod as CE. For OER electrocatalysts, Pt is much better than CR, even though some journal editors ask me to use Carbon as CE. Thx again.

@M. R. Reda, Dear Mr. Reda, thx for your answer,the potential ranges from 0.25 to 0.55 (VS. SCE), I think the potential is not too high. And at least l, Pt is more stable than Carbon rod in the alkaline solution (pH=13.56).

It seems that the whole story is:

1. Reviewers or editor ask you to provide the data with Carbon Counter Electrode.

2. You don't want to do it.

My answer is:

Do what reviewer ask you to do, regardless it makes sense or not.