Preparation and Photoelectrochemical Water Oxidation of Hematite Nanobelts Containing Highly Ordered Oxygen Vacancies

Aiming at the performance-limiting characteristics of short hole diffusion length (2-4 nm) and sluggish water oxidation kinetics in hematite (alpha-Fe2O3), we developed hematite nanobelts containing ordered oxygen vacancies by catalyzed oxidation of palladium nanocrystals for efficient photoelectrochemical (PEC) water splitting. Morphologies and structures of as-prepared films were characterized by different methods. Results show that ordered oxygen vacancies was observed in hematite nanobelts with a periodicity of 1.48 nm corresponding to ten times of (11 (2) over bar) interplanar spacing. The PEC performance of the hematite nanobelts exhibits stable photocurrent density of 3.3 mA center dot cm(-2), the corresponding hydrogen evolution rate of 29.46 mu mol center dot cm(-2)center dot h(-1), and an early onset potential of 0.587 V (vs. RHE) without additional oxygen evolution reaction cocatalysts. The enhanced performance can be attributed to the introduced ordered oxygen vacancies which can increase the carrier density, greatly accelerate the surface holes transfer, and act as surface active sites to significantly promote the surface water oxidation reaction.

Automated summary

Researchers developed hematite nanobelts containing ordered oxygen vacancies for efficient photoelectrochemical water splitting. The enhanced performance is attributed to the introduced ordered oxygen vacancies, which can increase the carrier density and accelerate surface holes transfer, acting as active sites to promote the surface water oxidation reaction.