As shown in the image, we got a high impedance of 170 ohm in a three-electrode cell with Pt wire as counter, glassy carbon as work and Ag/AgCl as reference in 0.1M KHCO3 solution. While if we replace the work electrode with a Pt wire or a piece of Cu foil, the resistance came out 20 ohm, which is more reasonable. We have tried difference GC electrode and we have always such a high resistance. Somebody knows why ? thanks!
Can you simply measure the el. contact resistance of your glassy carbon ?
Note for contact resistance : use, please, a simple Ohmmeter.
I measured the resistance between the glassy carbon and the contact point (RDE). It is 0.4 ohm. It seems the glassy carbon electrode is not so high.
yes, 0.4 ohm is very good. A next step may be to clean the lower part of the surface (of the glassy carbon electrode) in contact wrh the el. solution.
I agree. 0.4ohm is good. Check out the voltage drop between the "cleaned" glassy carbon electrode and the reference electrode. Usually it is the IR drop that causes problems.
Thanks for your suggestions. Actually we just want to use the GC electrode as substrate
As per "Ioannis Samaras" suggestion just clean in properly with alumina powder and dry it in air with out usage of tissue paper.Also add fresh 0.1M KHCO3 solution in Ag/Agcl.
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