The importance of properly correcting the electric double layer effect in unravelling the intrinsic kinetics of electrode reactions

Understanding the effects of the electric double layer (EDL) on electrode kinetics is of great importance for improving the performance of electrochemical devices. In this work, by using the HER at Au(111) in x M HClO4 ​+ ​(1−x) M NaClO4 or NaOH as a model reaction, the intrinsic kinetic parameters for HER has been unveiled based on the modified Poisson-Nernst-Planck equations and the Frumkin-Butler-Volmer theory. Our analysis reveals that i) the EDL effects induced changes in proton concentration cH+RP and electric potential ϕRP at the reaction plane are the main reason for the difference of HER current in the cases with x M HClO4 and x M HClO4 ​+ ​(1−x) M NaClO4; ii) the EDL effects are the main origin for the difference in HER current between acidic and alkaline solutions at the Au(111). Our work demonstrates that microkinetic simulation with properly considering the EDL effects is important for unravelling intrinsic reaction kinetics of electrocatalytic reactions.