More on the Importance of a Rate-Determining Step

This chapter is about electrocatalysis, in practice, how to make an electrochemical reaction go faster (thus reducing costs, etc.). 

Many electrode reactions are consecutive in nature and if one has a consecutive reaction—and it contains only a few steps—it is indeed a common experience that one of the successive reactions has a much greater influence on the rate than the others. In extreme cases, the one reaction in a sequence of, say, four, has a 99% control over the rates of the other reactions in the series. 

we are going to present several pathways to electrocatalysis, and one can see that, if this one reaction, the rate-determining one, is clearly the one to attempt to speed up and is the one that would make the entire reaction go faster. The other reaction steps will fit in. If we can make the r.d.s. go faster, the whole reaction will go faster, and that is the electrocatalysis we want. 

But to be able to make the r.d.s. go faster, one needs to know much about the structure of the surface and how the atoms in the r.d.s. are bonded to the surface of the electrode catalyst. It may be a special feature of the surface, which is particularly catalytic, and perhaps this can be adjusted so that the r.d.s. is speeded up. 

Of course, this is a crude sketch, a bare description of electrocatalysis in simple cases, but it does stress that to know which step is rate determining is more than half way to determining how to catalyze the overall reaction.  

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