Room temperature surface modification of ultrathin FeOOH cocatalysts on Fe2O3 photoanodes for high photoelectrochemical water splitting

Abstract

An ultrathin FeOOH cocatalyst is deposited on α-Fe2O3 photoanodes in a simple room temperature immersion process for efficient photoelectrochemical (PEC) water splitting. The prepared FeOOH/Fe2O3 photoanode has a photocurrent density of up to 2.4 mA/cm2 at 1.23 V versus reversible hydrogen electrode (RHE), and the photocurrent density is increased by about 160% compared to the bare Fe2O3 of 1.55 mA/cm2. 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 Fe2O3.