Experimental and Computational Investigation of the Optical, Electronic, and Electrochemical Properties of Hydrogenated α-Fe₂O₃

With the combination of experimental and computational approaches, the impact of hydrogenation on the optical, electronic and electrochemical properties of Fe₂O₃ for water splitting have been studied. Under high pressure, hydrogen incorporation into the Fe₂O₃ lattice has been achieved, and hydrogen dopants can be released with heat treatment. With H-doping, magnetite Fe₃O₄ has been found to form at the edge of Fe₂O₃ nanoparticles. H-incorporation can narrow the band gap by ∼0.4 eV and slightly reduce the overpotential (by 140 mV) for oxygen evolution reaction, but due to the localization of hydrogen (bonded with oxygen), a slightly lower charge carrier density resulted. Computational studies reveal that all of the above changes are essentially related to the local states brought by H-dopants. This study provides an in-depth understanding of the optical, electronic, and catalytic properties of hydrogenated Fe₂O₃.