In2S3/F-Fe2O3 type-II heterojunction bonded by interfacial S-O for enhanced charge separation and transport in photoelectrochemical water oxidation

The application of hematite(alpha-Fe2O3)-based photoanodes in photoelectrochemical (PEC) water oxidation has been hampered by disgusting charge recombination and difficult carrier migration. Herein, we modified indium sulfide (In2S3) nanoparticles on the surface of fluorine-doped alpha-Fe2O3 (F-Fe2O3) nanorods. The In2S3/F-Fe2O3 heterostructure bonded by S-O chemical bond shows a superior photocurrent density of 2.21 mA cm(-2) at 1.23 V versus reversible hydrogen electrode (around 3.45 times higher than that of pristine alpha-Fe2O3). In-depth investigations show that In2S3/F-Fe2O3 has significantly increased donor density and decreased charge transfer resistance. Simultaneously, In2S3 decorated with S-O bond could reduce the surface defect states. Further studies of energy band location reveal the formation of type-II heterojunction between In2S3 and F-Fe2O3. The unique heterostructure provides a powerful driving force for charge separation and transport, resulting in satisfactory bulk phase and surface separation efficiency. This work provides ideas for the design and study of multicomponent photoanodes.

Automated summary

The study utilized indium sulfide nanoparticles to modify the surface of fluorine-doped alpha-Fe2O3 nanorods, forming an In2S3/F-Fe2O3 heterostructure. This heterostructure showed increased photocurrent density, reduced charge transfer resistance, decreased surface defect states, and improved charge separation and transport efficiency through the formation of a type-II heterojunction.