Have you checked that all the constants/ parameters have the proper units?

Also, is your current axis in natural log (ln) or log? Note that ln (x) = 2.3 log (x) so if the axis is in log, the equation should contain 2.3

Hi Isaiah Owusu Gyan, Thank you very much for your quick response. My plots are in ln scale so there is no point of 2.3. I tried all the parameters in SI units. For example, F in C/mol, R in J/mol. K, T in K, J in A/cm2 and E in Volts. If you find anything wrong, pls let me know.

With regards,

Dr. N .K. Reddy

Hi N.K. Reddy, please go through following attached paper. My suggestion is choosing the slope from the plot is very important point otherwise u will not get proper value. While choosing slope u should not required to consider total curve only where steady state is existing those values only u should take. Please refer more papers. I think my suggestion may useful for u otherwise ignore.

Hi, Krishna, extracting the slope is not my problem. My values are comparable with literature data. Unfortunate issues is I am not able to calculate charge transfer coefficient value. For example, in J. Mater. Chem., 2012, 22, 17113–17120 paper, they reported charge transfer coefficient as  0.275 for the slope of 0.137. I don't know how they got 0.275  from 0.137 slop.

If you find any solution pls let me know.

the cathodic and anodic transfer coefficients by the quantities αc = –(RT/F)(dln|jc|/dE) and αa = (RT/F)(dlnja/dE), which are independent of any mechanistic consideration