Three Dimensional ATO Inverse Opal Based Hierarchical Nanostructures:Facile Preparation And Photoelectrochemical Performance

Energy crisis and environmental pollution have become two major problems restricting economic development.Photoelectrochemical water splitting is a green method to generate hydrogen through electrolysis of water by sunlight.Some semiconductor materials,such as TiO₂,Fe₂O₃,Bi VO₄ and so on,have been developed as photoanode materials for water splitting.However,these semiconductors may suffer several drawbacks,such as short charge diffusion length,poor electrical conductivity,low absorption coefficient,and so on,which resulted in limited PEC performance.In this paper,three-dimensional?3D?Sb-doped Sn O2?ATO?inverse opal structure was first fabricated as conductive scaffolds,then two semiconductors,Fe₂O₃ and TiO₂ were loaded on 3D ATO inverse opal separately,hence two 3D ATO inverse opal based hierarchical nanostructures was fabricated.The PEC performance of these two composite nanostructures were systematically studied.The main research contents are as follows:?1?Monodispersed polystyrene?PS?microspheres with different diameters was synthesized by soap-free emulsion polymerization method.Then the PS microspheres were self-assembled into 3D colloidal crystals by vertical sedimentation method.The as-self-assembled colloidal crystal exhibit face-centered cubic structure with long range order and little lattice defect.Sol-gel method was then employed to fabricate ATO inverse opal with different Sb doping amounts using as-prepared colloidal crystal as template.?2?3D ATO/Fe₂O₃ composite structure was successfully prepared by hydrothermal method using 3D ATO inverse opal as scaffold.The effects of Sb doping amount,particle size and template thickness on the photoelectrochemical properties of 3D ATO template were investigated.The results showed that:?1?ATO played an important role in the system.Firstly,the three-dimensional macroporous structure improved the utilization of light,and the large specific surface area provided more active sites.Secondly,as a conductive skeleton,3D ATO inverse opal structure was beneficial for the rapid transmission of charge carriers,which improved the photoelectric conversion efficiency.?2?The influence of Sb doping amounts on PEC performance was studied.It is discovered that when the Sb doping amounts?feed molar ratio Sb/?Sn+Sn??was 25%,the photocurrent density of the of 3D ATO/Fe₂O₃ composite structure reached 1.04 m A/cm² at 1.23 V vs RHE.?3?3D ATO/TiO₂ composite structure was successfully prepared by chemical bath deposition using 3D ATO inverse opal as template.The effects of the concentration of the precursor solution and the reaction time on the photoelectrochemical properties were investigated.The results showed that these conditions could affect the length and arrangement of TiO₂ nanorods.When the length of TiO₂ nanorods were proper,the PEC performance of 3D ATO/ TiO₂ composite structure was improved,and the photocurrent density reached 0.78 m A/ cm² at 1.23 V vs.RHE under the best conditions.