Room Temperature Surface Modification of Ultrathin FeOOH Cocatalysts on Fe2O3 Photoanodes for High Photoelectrochemical Water Splitting

An ultrathin FeOOH cocatalyst is deposited on α -Fe 2 O 3 photoanodes in a simple room temperature immersion process for efficient photoelectrochemical (PEC) water splitting. The prepared FeOOH/Fe 2 O 3 photoanode has a photocurrent density of up to 2.4 mA/cm 2 at 1.23 V versus reversible hydrogen electrode (RHE), and the photocurrent density is increased by about 160% compared to the bare Fe 2 O 3 of 1.55 mA/cm 2 . An obvious cathodic shift of the photocurrent onset potential from 0.661 to 0.582 V was also observed, and excellent stability was maintained with almost no deterioration for 5 h. The enhanced PEC performance is attributed to the decrease of the interfacial resistance between electrode and electrolyte and the increase of the injection efficiency of holes in Fe 2 O 3 .