Recently I am doing HER experiment by using amorphous MoSx.
I controlled the experiment conditions and found that, some samples have low Tafel Slope(which is good) but low exchange current density and high onset potential than others (which is bad).
Is this possible?
PS: Many authors always report their best sample have lowest Tafel slopes, highest exchange current densities and lowest onset potentials.
Is this trend not necessarily true? Sample with lowest Tafel slope could have lower exchange current density than other samples?
I think that your results are completely logical. The electrochemical performance of your electrodes are related to them composition and structure, where porous distribution is one of the most important factors. I think your low exchange current may be associated with a minor solution access through the porous.
I suggest you to determine your active surface in each sample.
Hi Jordi Carrillo Abad,
Thank you for your answer. The dispersion of catalyst, supporter used will affect all these parameters. Hence, there is no direct correlation of these "positive parameters".
Warmest regards,
SHU HEARN
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