Micro-Nano-Structured Fe2O3:Ti/ZnFe2O4 Heterojunction Films for Water Oxidation

Iron(III) oxide photoelectrodes show promise in water oxidation applications. In this study, micro-nano-structured hematite films are synthesized, and Ti ions are doped to improve photoelectric conversion efficiency. The photocurrent increases for enhanced electrical conductivity. Further enhanced photocurrent is achieved for Fe2O3:Ti/ZnFe2O4 heterojunction electrodes. Cyclic voltammograms combined with optical absorbance examinations demonstrate that the conduction and valence band edges of ZnFe2O4 shift from those of Ti doped Fe2O3 to the negative direction, which facilitates the efficient separation of electron-hole pairs at the Fe2O3:Ti/ZnFe2O4 interface. These findings demonstrate that, by doping hematite and by engineering the interface between the hematite and the electrolyte, charge separation can be effectively promoted and photocurrent density can be dramatically increased.