Study of photoelectrochemical corrosion of lead oxide in alkaline solutionby the rotating ring-disk electrode technique

Photoelectrochemical corrosion of n-type alpha-PbO electrodes in aqueous Fe (CN)(6)(3-/4-) and I-/I-3(-) electrolytes using the rotating ring-disk elec trode technique has been investigated. The alpha-PbO thin film is found to be more stable in I-/I-3(-) (48%) than in Fe(CN)(6)(3-/4-) electrolyte (10% ). Preferential adsorption of iodide ions decreases the photocorrosion reac tion of holes with alpha-PbO. Addition of CsI (0.4 mM) to the I-/I-3(-) ele ctrolyte decreases the photocorrosion from 48% to less than 10%. Cs+ ions p erhaps nullify the effect of negatively charged surface states of alpha-PbO , thus minimizing the trapping of holes at the surface of alpha-PbO and hen ce decrease the possibility of photocorrosion of lead oxide with holes.