Dear readers, I am conducting cyclic voltammetry experiments and I wanted to eliminate the capacitive current to better distinguish the current peaks and avoid error. So the approach that I took is to measure the CV of the solution without analyte (only solvent + supporting electrolyte), and then subtract it from the CV of the analyte (3mM of S8). The set-up that I am using is Ag/AgCl=Ref; Pt disk 2mm=CE and glassy carbon 2mm = WE. The solutions that I am working with are 0.1M LiClO4 in DMF and 0.1M TBAB in DMF, and all of the experiments are made under argon atmosphere. I share with you some CVs before and after corrections. The main problem that I am facing is the oscillating current of the blank solutions that results in "weird" corrected CVs.
Please look at the following below links which may help you in your analysis:
https://www.palmsenscorrosion.com/knowledgebase/capacitive-current/
https://www2.chemistry.msu.edu/courses/cem419/cem372cyclicvoltammetry.pdf
https://pubs.acs.org/doi/pdf/10.1021/acs.jchemed.7b00361
Thanks
Dear Isam Eldin Hussein Elgailani , I read the documents that you have suggested (already read the last paper in the past), it provides basic introduction for cyclic voltammetry. I am familiar with the theory (thanks to the famous book of Electrochemical Methods: Fundamentals and Applications by A. J. Bard and L. R. Faulkner). What I am looking for is some practical tips/advices that allow me to obtain well shaped voltammograms (after removal of the capacitive current).
Thanks for help.
If you use the voltammetric analyser allready will substract the blank current from the analyte votammogram
Dear Amer Al-Taee , I am using Zahner-XPOT potentiostat with a monitoring software called "PPinspector" which doesn't practically do anything... I need to realize a lot of corrections by myself, so please if you can suggest a software able to remove blank current automatically cite it here. Thanks.
It looks as if your problem is not the capacitive currents, which in reality on smooth (polished, if it is your case) flat electrodes are insignificant at these quite small scan rates. Nevertheless, your background curves at different V reveal Faradaic processes tied obviously with some impurities in the blank solutions. Important problem here from my old experience is when you add your electroactive substance the background currents can be partially suppressed (not always) by adsorption of this substance on the electrode surface. This suppression, however, depends on nature and concentration of all members of the solution (including solvent and background electrolyte). Therefore, when you subtract the background currents from your CVs with the analyte you can subtract more current than necessary and you can get strange results e.g. reverse currents etc. It follows from here that to improve quality of your CVs you have a few possibilities. For example, first – clean your solvent and background electrolyte salts or buy these ones of better quality; second – increase area of your working electrode; third - change Pt by glasscarbon; do not subtract; fourth - may be something else, it depends. I recommend you to read my old paper on effect of typical impurities of water in DMF on electrochemistry on Pt cathode, as well as literature cited in.
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