In-situ surface reconstruction in Pt and P co-treated hematite for enhanced water oxidation

Abstract Self-reconstruction of metal phosphates has been proved to be very effective in improving the OER activity. Herein an in-situ surface reconstruction in Pt and P co-treated hematite photoanode for synergistically enhanced water oxidation is firstly demonstrated to synergistically enhance the water oxidation, which exhibits an improved photocurrent density of 2.61 mA cm-2 at 1.23 V vs. RHE. After the deposition of FeNiOOH cocatalyst, a remarkable performance of 3.79 mA cm-2 at 1.23 V vs. RHE is also achieved. Various measurements reveal that during the P-treatment, the Pt-incorporation can accelerate the reaction between PH3 and Fe2O3, consequently resulting in a more visible FePO4 overlayer on the hematite surface. Then, under working conditions, the FePO4 can be self-reconstructed to an efficient FeOOH cocatalyst to provide more active sites for the faster OER kinetics. Simultaneously, the OER activity is further facilitated by Pt-incorporation, which prominently promotes the charge transport and separation with the increased donor density.