Measurement of Potentials at Semiconductor and Metal Particles Under Irradiation

3 Measurement of Potentials at Semiconductor and Metal Particles Under Irradiation 

It is also possible to measure the potential of semiconductors under various conditions (electrolyte, solution) and applied potentials with and without irradiation when a semiconductor photocatalyst is employed as an electrode [11], The rest potential measurement of a semiconductor should provide a good estimate of the potentials at equilibrium under dark conditions and steady-state photoirradiation. A lack of equilibration is often observed between metal/semiconductor and the redox potential in the solution this can be ascribed to corrosion of the semiconductor, to formation of a surface film (e.g., oxide), or to inherently slow electron transfer across the interface [67], making the situation more complex. It is thus preferable to directly measure the potentials during the photocatalytic process. 

FIGURE 11.12 (a) Potential-dependent SEIRA spectra of adsorbed CO on Pt particles 

TABLE 11.4 Potential shift by a single electron incident on a Pt hemispherical particle (assnming a constant capacitance of 20 iF cm ) 

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