I have tried H2 UPD and Cu UPD to no avail. The voltammograms do not show the required peaks on the desorption side to calculate the ECSA. The signal is quite weak to discern over the double layer capacitance. Increasing the scan rate to 300mV/s did not yield good results either.
The Pt loadings are quite low (between 0.1 to 0.005 mg/cm2) and cannot be changed. Also my target is to calculate the ECSA for the electrodes in this condition itself, i.e., on the carbon paper and not on glassy carbon.
Reeshab Goenka I think it is performed on the adsorption side peak. Under Potential Hydrogen reduction (Hupd) is assumed as monolayer deposition of Hydrogen on the platinum surface. By integrating the charge of hydrogen reduction peak, the ECSA is usually calculated. Remember that you also have to subtract the contribution of double layer. What is the potential window did you use?
Madhavan Kasinathan You are right. I did the HUPD from 50mV to 1.2V vs RHE but I did not get the signature voltammogram of Pt that we usually get when we deposit the catalyst ink on a glassy carbon electrode. I am not seeing the hydrogen desorption peaks which we usually use to calculate the ECSA. There is just a single hydrogen adsorption peak and when the voltage reversal occurs, the current remains negative. See attached file.
The working electrode is carbon paper coated with 10% PtC of the given loading with a Pt wire counter. The tests are done with SCE and then normalized on the basis of RHE.
Similar results are obtained for Cu UPD.
Be aware that most [modern] potentiostats are digital and so if you want to capture electron transfer from adsorbed species (or double layer capacitance) you need to make sure that the system you are using either has a surface mode, or a linear (analog) scan--either of those works. The default settings for CV on most digital potentiostats will not capture the current you are interested in.
Jacob Ketter I got the Pt signature voltammogram when I switched my Pt wire counter electrode to be the working electrode. So I guess the settings on my potentiostat was proper.
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