Electrochemical Stability of p ‐ GaInP2 in Aqueous Electrolytes Toward Photoelectrochemical Water Splitting

With an eye toward developing a photoelectrochemical system for water splitting using , the electrochemical stability of was studied in 10 M KOH, , and a phosphate buffer of pH 7. It was found that in the dark, the electrode is susceptible to corrosion in all investigated solutions. Upon illumination, the anodic corrosion current increases. Under cathodic polarization in 10 M KOH, the electrode shows saturated photocurrent density, however the photocurrent slowly decreases with time due to the precipitation of an indium‐enriched oxide. In , the anodic process can be inhibited under relatively low cathodic potentials, and stable photocurrents can be obtained. In neutral solution, is covered by a semi‐insulating oxide film and the observed photocurrent densities are much lower than those in 10 M KOH and .