PHOTOADMITTANCE OF 2-STEP CHARGE-TRANSFER PROCESSES ON SEMICONDUCTOR ELECTRODES - EXAMPLE OF HYDROGEN EVOLUTION REACTION

The photoadmittance of a two-step charge transfer sequence with chemis orbed intermediate on semiconductor electrodes has been treated, takin g explicitly into account the nonlinear adsorption kinetics. A promine nt example of this reaction type is the hydrogen evolution reaction. A significantly different partial charge transfer of m-type in the cons ecutive steps of the hydrogen reaction has been evaluated, in three in dependent ways. A numerical simulation of the two-step photoadmittance provides estimates of rate coefficients and adsorption parameters. Ad mittance phenomena in dark reactions are briefly considered.