3D core-shell WO3@α-Fe2O3 photoanode modified by ultrathin FeOOH layer for enhanced photoelectrochemical performances

Abstract The solar light absorption efficiency as well as the carrier separation and transfer efficiency in the bulk and on the surface of the photoanodes are still the main challenges for efficient photoelectrochemical (PEC) water splitting. Hence, in this work, a 3D core-shell WO3@α-Fe2O3 photoanode modified by ultrathin FeOOH layer was designed and fabricated for the first time to maximize respective merits of 1D WO3 (excellent electron transport pathways), α-Fe2O3 (strong visible light absorption) and FeOOH (a hole transfer) to achieve efficient PEC performances. As a result, the as-fabricated WO3@α-Fe2O3/FeOOH photoanode exhibits a 120 mV negatively shift in onset potential and yields a photocurrent density of 1.12 mA/cm2 at 1.23 V vs. RHE, which is 1.72 and 3.73 times than that of WO3@α-Fe2O3 and WO3 photoanodes, respectively. Moreover, this work may provide an effective strategy of maximizing the advantages of each component in the composite photoelectrode to achieve effective PEC performance.