Sn-doped 3D ATO inverse opal/hematite hierarchical structures: facile fabrication and efficient photoelectrochemical...

The coupling of hematite with a three-dimensional (3D) conductive inverse opal (IO) skeleton provides an efficient route to enhance the photoelectrochemical (PEC) properties of hematite without changing its chemical composition. In this work, novel 3D antimony-doped SnO₂ (ATO) IO/hematite heterostructures were facilely fabricated, and their PEC properties were thoroughly studied. Analysis of the morphologies and photocurrent densities of the 3D ATO IO//Fe₂O₃ heterostructures reveals that the high conductivity of the ATO skeleton as well as the high specific area and good light harvesting properties of the 3D IO structures greatly enhance their PEC performance. In particular, further morphology tuning by changing the diameters of the ATO IO skeletons could optimize the optical and electrical properties of the as-prepared heterostructures, demonstrating the important influence of morphology engineering on PEC performance. Moreover, after a simple Sn-doping process, the PEC properties of the as-prepared structure could be further enhanced; a photocurrent density of 1.28 mA cm^-2 at 1.23 V vs. RHE was obtained under AM 1.5G illumination.