c-In2O3/α-Fe2O3 heterojunction photoanodes for water oxidation

Hematite (α-Fe2O3) is supposed to be one of the most promising photoanode candidates for solar-driven water splitting. However, the photoelectrochemical (PEC) performance of α-Fe2O3 is limited by fast recombination of carriers. In this work, we demonstrate that the recombination of α-Fe2O3 films could be suppressed by forming the heterojunction structure with cubic-In2O3. By utilizing the magnetron sputtering method, the In2O3/α-Fe2O3 films were prepared when the In concentration exceeded its solubility in α-Fe2O3 matrix, which was confirmed by the XRD and TEM analysis. The dependence of charge separation on heterojunction structure was evidenced by Mott–Schottky and EIS analyses. It was found that the enhanced separation of holes and electrons in α-Fe2O3 films contributed to higher PEC performance.