Semiconductor Electrodes: XXXVI . Characteristics of , Electrodes in Aqueous Solution

Capacitance and voltammetric measurements were employed to investigate the electrochemical and photoelectrochemical (PEC) behavior of ,, and single crystal electrodes in aqueous solutions containing various redox couples (, , , Fe2+/ Fe3+, , and , where HV is heptyl viologen and MV is methyl viologen). In supporting electrolyte , the conduction bandedges of and , determined from the capacitance measurement, are at −0.14 and −0.44V vs. SCE, respectively, and the valence bandedge of is at 0.93V vs. SCE. A bandgap of 1.4 eV for was determined either from the photocurrent action spectrum or from the capacitance measurement. The specific effects of iodide on the capacitance and voltammetric behavior of layer‐type compounds are compared. The characteristics of several PEC cells are also described.