After CO2 Electrochemical reduction on 6 samples, i obtained both gaseous and liquid products from GC-MS and NMR respectively. i quantified the liquid products by integrating each peak. for example I quantified the formate by dividing the peak area by 1 (since only 1 proton is resposible for that peak) and then the peak area of DMSO(internal standard) of known concentration was divided by 6 (since 6 protons are responsible for that peak). Then i divided the area per nuclei of the Formate by area per nuclei of the DMSO to get the relative area. with my standard curve of formate, i calculated the concentration from the equation of the standard curve obtained from Microsoft excel.

using FE=C x n x F/Q x100 where C is concentration, n number of electrons transferred for the formation of a product, Q total charge obtained by integrating all the currents i and the corresponding time t. I calculated the FE of both the gaseous and liquid products ensuring that all the units cancel out. However summing up all the FE on each catalyst, i noticed that on some catalysts the TOTAL FE WAS HIGHER THAN 100% (103% up to140%), while others in which less number of liquid products were obtained had TOTAL FE way less than 100% (30% to 55%). I find it difficult to account for the remaining FE. I detected H2,CO,CH4,HCOO- and CH3OH on the first 3 samples and only H2,CO,CH4 and HCOO- were detected on the remaining 3 which give lesser than 100% Total FE.

Please must my Total FE be approx.100%, is there mistake in my liquid product quantification?

I look forward to your contribution to my challenges.

Thank you.

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