Oxygen vacancies boosted photoelectrochemical performance of -Fe2O3 photoanode via butane flame annealing

In this study, oxygen vacancies were introduced into the hematite (alpha-Fe2O3) photoanode via a simple and rapid butane flame annealing method. The presence of oxygen vacancies were demonstrated by high-resolution transmission electron microscopy (HRTEM), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS). The photocurrent density of optimum alpha-Fe2O3 electrodes was 0.67 mA cm-2 at 1.23 VRHE, about 2.7 times higher than that of N2 annealed electrode. Our study showed that butane flame annealing process can introduce oxygen vacancies defects in Fe2O3 electrodes, which would improve carrier transfer efficiency, increase electron density, enhance water oxidation activity, and narrow the light optical bandgap. The use of butane flame annealing is a simple and effective strategy to enhance the PEC performance of hematite thin films.