Study On The Controllable Preparation And Photoelectrochemical Properties Of Ordered Composite Structure Based On Three-dimensional ATO Inverse Opal

With the continuous development of modern society,the use of fossil fuels will inevitably caused environmental pollution and resource shortages.Therefore,it is imperative to develop green,economical,and superior new energy to substitute the fossil fuels.Hydrogen energy is one of the best choices of the new energy,which benefits from the widespread sources,low risk factor and pollution-free within secondary combustion.Among various methods of producing hydrogen,Photoelectro-chemical(PEC)water splitting is the most promising and environmental-friendly program,of which water and sunlight serves as the sources lead to no hazardous production were made.However,the efficiency of PEC water splitting is limited by the properties of photoelectrodes,such as light absorption performance,carrier recombin-ation rate,and hole migration kinetics at the interface,so it has not been able to achieve large-scale applications at present.The reasonable design for the composition and morphology of the photoanode is an important way to improve the performance of PEC water splitting.Sb-doped Sn O₂(ATO)with inverse opal(IO)structure(3D ATO)is an ordered macroporous structure.its periodic macroporous skeleton significantly adds the acreage of the specific surface area,and it adds the interaction of incident light and the electrode to facilitate light absorption.In this work,a photoanode is designed with 3D ATO as a conductive framework,and its PEC performance is systematically studied.The specific research content is as follows:(1)Using three-dimensional(3D)colloidal crystals as a structural template,3D ATO was prepared by the sol-gel method,which was used as a 3D macroporous conductive skeleton.Secondly TiO₂ nanorods were loaded onto the 3D ATO skeleton by hydrothermal method hydrothermal method.Then,by converting the surface of the as-prepared TiO₂nanorods into SrTiO₃ by hydrothermal method,3D ATO/TiO₂@SrTiO₃ core-shell heterojunction structure were obtained.The effect of the reaction time of TiO₂ to SrTiO₃ conversion on the composition and morphology of the photoanode was characterized by FESEM,TEM,XRD and XPS.It was found that with the increase of the conversion time,the TiO₂ nanorods gradually transformed into granular SrTiO₃.The effect of 3D ordered macroporous structure and SrTiO₃ loading on the PEC performance of TiO₂ photoanode was characterized by LSV,it curve,EIS and PL,etc.It was found that the formation of TiO₂/SrTiO₃ heterojunction can effectively improve the Charge separation and transfer on the surface of TiO₂.At the same time,the introduction of a 3D ordered macroporous structure can increase the specific surface area of the photoanode and increase the interaction between the material and the light,thereby improving the PEC performance of the photoanode.The3D ATO/TiO₂@SrTiO₃ core-shell heterogeneous obtained after partial conversion of TiO₂ to SrTiO₃ has a photocurrent of 1.17 m A/cm² at a bias voltage of 1.23 V vs.RHE,which is about 1.5 times that of 3D ATO/TiO₂,and 3.6 times of ATO/TiO₂.(2)On the basis of the previous work,hydrothermal method was used to obtain titanium(Ti)doped iron oxide nanorods(Fe₂O₃(Ti))on the 3D ATO skeleton,thereby fabricating a 3D ordered microporous ATO/Fe₂O₃(Ti)composite structure.FESEM,TEM,XRD and XPS were used to characterize the effect of Ti⁴⁺ion doping concentration on the morphology of 3D ATO/Fe₂O₃(Ti)composite structure.It was found that Ti4+doping would affect the nucleation growth of Fe OOH,which in turn affected length of Fe₂O₃ nanorods.The effects of the 3D ordered macroporous structure and Ti⁴⁺ion doping concentration on the PEC performance of 3D ATO/Fe₂O₃(Ti)were characterized by LSV,it curve,EIS and PL.It was found that the doping of Ti⁴⁺effectively improved the conductivity of Fe₂O₃.Reducing the recombination of carriers,thereby significantly improving its photoelectrochemical performance.In addition,the introduction of a 3D ordered macroporous structure can increase the specific surface area of the photoanode and increase the interaction between the material and the light,thereby improving the PEC performance of the photoanode.The photocurrent of Ti⁴⁺doped 3D ATO/Fe₂O₃ is 1.31m A/cm² at a bias voltage of 1.23 V vs.RHE,which is about 2.1-fold of 3D ATO/Fe₂O₃.