Chemical Steps of the Dissolution Reaction

It was pointed out many years ago [3, 27] that the anodic dissolution of III-V semiconductors in aqueous media not only consists of electrochemical steps, but must also involve chemical steps in which H2O molecules or OH ions participate. This follows from mere consideration of the overall reaction Eqs. (9) to (14) and, as 

The latter conclusion appeared in turn to be interpretable by adopting the following modified version of the DX dissolution mechanism, including a chemical step and therefore symbohzed by DXC  

The steady-state condition for X2 now becomes with jcj the surface concentration of Xj-OH  

(42) is indeed obtained, with k equal to the following expression  

Remembering that Xj actually represents a positively charged surface intermediate, Eq (46) may be considered to represent the neutralization of this positive charge by reaction with H2O. It is reasonable to assume that further electrochemical reaction will, for electrostatic reasons, rather occur between the neutral entity X)-OH and the positively charged intermediate Xj than between two positive Xj intermediates (note that the stabilization kinetics yield no information on chemical 

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