Tailoring growth process of heteroatom-doped hematite homojunction electrodes for photoelectrochemical catalysis of water oxidation reaction

Abstract

Enhancing electrical conductivity is necessary to widen application of hematite (α-Fe2O3) as efficient photocatalyst for water oxidation. Doping heteroatoms and developing p-n junction are effective ways for improving carrier density and charge transfer. Heteroatoms of Ti and Mn are doped in hematite to establish p-n homojunction using hydrothermal and annealing processes for catalyzing water oxidation in this work. Ti-doping amount in Ti-doped hematite layer (Ti:Fe2O3) and hydrothermal duration for developing Mn-doped hematite layer (Mn:Fe2O3) are studied to optimize photoelectrochemical performance of hematite homojunction electrode. Optimized Mn:Fe2O3/Ti:Fe2O3 electrode prepared using 9 μl Ti precursor in hydrothermal solution and 45 min as hydrothermal time for constructing Mn:Fe2O3 shows highest photocurrent density of 2.09 mA/cm2 at 1.60 VRHE, owing to small charge-transfer resistance and high carrier density. This study illustrates importance of designing separated layers for establishing homojunction and provides useful indications for picturing recipe for creating efficient photoanode for catalyzing water oxidation.