Photoadmittance of two step charge transfer processes on semiconductor electrodes. Example of hydrogen evolution reaction

The photoadmittance of a two-step charge transfer sequence with chemisorbed intermediate on semiconductor electrodes has been treated, taking explicitly into account the nonlinear adsorption kinetics. A prominent example of this reaction type is the hydrogen evolution reaction. A significantly different partial charge transfer of m -type in the consecutive steps of the hydrogen reaction has been evaluated, in three independent ways. A numerical simulation of the two-step photoadmittance provides estimates of rate coefficients and adsorption parameters. Admittance phenomena in dark reactions are briefly considered.