Although is known to be unstable in presence of iodine, it is shown that this semiconductor can be efficiently stabilized by using highly concentrated acidified iodide aqueous solutions. The effects of proton activity and iodine and iodide concentrations on the electrode stability are investigated by means of rotating ring‐disk experiments, RHEED observations, and chemical analysis of the electrolyte. Impedance measurements show a positive shift of the bandedges of with iodine concentration and illumination level. At a nominal pH of 0, the stabilization ratio is measured close to 100% (80%) for in contact with a solution, respectively. Under illumination, the redox level is found to be favorably located near midgap. Kinetic analysis of the competing hole reactions yields a satisfactory simulation of vs. I− concentration. The hole capture by reduced species is found to be proportional to the concentration of iodide ions, not to their activity, in contrast to expectation. Furthermore, it is shown that chemisorbed Ru3+ cations act as a catalyst for hole transfer and thus improve the stability of in solution.