Extracting nucleation rates from current–time transients. Comments on three papers by Abyaneh and Fleischmann published in this issue

Electrochemical nucleation presents the theorist with a number of problems. Perhaps the most difficult of these is how to model the appearance rate of crystals as a function of time. Recently, Abyaneh and Fleischmann published several papers in which they modelled the appearance rate of crystals as a first-order kinetic process. Though conceptually simple, I argue in this note that such an approach is seriously flawed. Indeed, it violates the basic physics of heterogeneous nucleation, because it omits consideration of spatial non-uniformities in the specific interfacial free energies of crystal ∣ solid interfaces. As a result, the first-order kinetic model fails to predict nucleation rate dispersion, which is known to occur in nature. A better model is needed.