Gradient Surface Gallium-Doped Hematite Photoelectrode for Enhanced Photoelectrochemical Water Oxidation

Zeyuan Wang; Linxiao Wu; Jinshui Cheng; Hao Chen; Jingshan Luo

doi:10.1021/acs.nanolett.4c04909

Gradient Surface Gallium-Doped Hematite Photoelectrode for Enhanced Photoelectrochemical Water Oxidation

Nano Lett. 2025 Jan 15;25(2):707-714. doi: 10.1021/acs.nanolett.4c04909. Epub 2024 Dec 30.

Authors

Zeyuan Wang¹, Linxiao Wu¹, Jinshui Cheng¹, Hao Chen¹, Jingshan Luo¹

Affiliation

¹ Institute of Photoelectronic Thin Film Devices and Technology, State Key Laboratory of Photovoltaic Materials and Cells, Tianjin Key Laboratory of Efficient Solar Energy Utilization, Ministry of Education Engineering Research Center of Thin Film Photoelectronic Technology, Nankai University, 300350 Tianjin, China.

PMID: 39810731
DOI: 10.1021/acs.nanolett.4c04909

Abstract

Hematite is a promising material for photoelectrochemical (PEC) water oxidation, but its photocurrent is limited by bulk charge recombination and poor oxidation kinetics. In this study, we report a high-performance Fe₂O₃ photoanode achieved through gradient surface gallium doping, utilizing a Ga₂O₃ overlayer on FeOOH precursors via atomic layer deposition (ALD) and co-annealing for Ga diffusion. The Ga-doped layer passivates surface states and modifies the band structure, creating a built-in electric field that enhances the charge separation efficiency. Following the electrodeposition of CoFeO_x as a cocatalyst, the resulting CoFe-Ga:Fe₂O₃ photoanode exhibited a notable negative shift in onset potential by approximately 100 mV, a high photocurrent density of 2.6 mA cm^-2 at 1.23 V versus RHE, and excellent long-term PEC stability over 40 h. This work presents an effective strategy for enhancing the PEC performance of photoelectrodes through advanced surface coatings.

Keywords: Fe2O3 photoanode; atomic layer deposition; gradient doping; photoelectrochemical water oxidation.