Hematite nanostructures for high efficient solar water splitting

Abstract

Hematite has emerged as a good photocatalyst for efficient solar water splitting due to its favorable optical band gap (2.1–2.2 eV), extraordinary chemical stability in oxidative environment, abundance, and low cost. According to theoretical prediction, the solar-to-hydrogen efficiency of hematite can be 16.8% and the water splitting photocurrent can be 12.6 mA cm−2. However, the practical performance of hematite for solar water splitting is far from the ideal case which has been limited by several factors such as poor conductivity, short lifetime of the excited-state carrier (10−12s), poor oxygen evolution reaction (OER) kinetics, short hole diffusion length (2–4nm), and improper band position for unassisted water splitting. In our recent work, enormous efforts have been focused on improving the performance of hematite nanostructure photoelectrode. Different methods such as morphology control, elemental doping, and improvement of the charge transport of hematite have been developed to improve the performance of hematite photoelectrode in solar water splitting.