Enhanced Photoelectrochemical Water Oxidation by Fabrication of p-LaFeO3/n-Fe2O3 Heterojunction on Hematite Nanorods

The LaFeO3 film exhibits interesting p-type behavior and stable photocatalytic hydrogen production in aqueous solution,: and we combine it with alpha-Fe2O3 nanorods to form a p-LaFeO3/n-Fe2O3 heterojunction to improve the photoeletrochemical (PEC) water oxidation performance of hematite. An atomic layerdeposition (ALD) technique is adopted to deposit La2O3 controllably on beta-FeOOH nahorods, and the p-LaFeO3/n-Fe2O3 heterojunction is achieved by post thermal treatment, which is evidenced by the XRD, XPS, and HRTEM images. Due to the Well-matched band levels Of LaFeO3 and alpha-Fe2O3, the onset potential for photocurrent is negatively shifted by similar to 50 mV. Meanwhile, the photocurrent density is promoted from 0.37 to 0.58 mA/cm(2) at 1.23 V versus RHE owing to the accelerated charge separation within the space depletion layer induced by the build-in potential. Furthermore, the heterojunction is further modified by CoOx cocatalyst to improve the surface water oxidation kinetics, and the photocurrent density is promoted to 1.12 mA/cm(2) at 1.23 V versus RHE. As a result, the incident photon-to-current conversion efficiency is further promoted to 25.13% at 400 nm, Our work demonstrates ALD with a prominent advantage in fabrication of the heterojunction with controllable film thickness, which plays an important role in the PEC water splitting application.