Study On The Construct Of Electron Transfer Layer And PEC Water Oxidation Performance Of Ti Doped Hematite Photoanode

With the rapid development of the industry,energy crisis and environmental pollution problem have become the main concern of people.The seeking of new?sustainable energy is an efficient method to resolve the energy and environment problem.Photoelectrochemistry?PEC?water splitting is regarded as an effective method,which can convert and store chemical energy directly from solar energy with the help of electric energy,the most important issue is selecting the suitable photocatalyst in the process.As we all know,the main factors contain light absorbing,the separation of photogenerated charge and the injection of photogenerated charge,which effect the PEC of photoanode.?-Fe₂O₃ photoanode has be regarded as a widely studied photoanode material with suitable bandgap,excellent chemical stability,non-toxic,non-pollution and low cost.But poor electrical conductivity and short lifetime of photogenerated carriers lead to poor photogenerated charge separation efficiency of?-Fe₂O₃,which limits its application in PEC water splitting.In order to improve the separation and transport of photogenerated charge,the electron transfer layer is constructed at the interface between FTO substrate and?-Fe₂O₃ photoanode,which can been regarded as crucial method to improve the separation efficiency of photogenerated charge and inhibit the bulk recombination of?-Fe₂O₃.Thus,it is of great siginificance to study the construction of electron transport layer for the PEC performance of photoanode.This paper mainly takes Ti-Fe₂O₃ as photoanode,In addition to take into account the carrier mobility of electron transfer layer,we emphasize on the band matching prin-ciple when choose the electron transfer layer,the further study the influence of the introduction of electron transfer layer on the photogenerated charge separation and transport behavior of Ti-Fe₂O₃ photoanode.The research contents are mainly divided into the following parts:1.The study on the influence of W-TiO₂ electron transfer layer on photogenerated charge behavior and PEC properties of Ti-Fe₂O₃ photoanode:Due to the Fermi level difference of Ti-Fe₂O₃ photoanode and FTO substrate,a Schotky barrier will be generated at the interface of Ti-Fe₂O₃/FTO,the existence of barrier will hinder the migration of photogenerated electron from Ti-Fe₂O₃ photoanode to FTO substrate.Based band matching principle,we introduce TiO₂ electron transport layer and W-TiO₂electron transport layer between Ti-Fe₂O₃ photoanode and FTO substrate.The results indicate that W-TiO₂,as an electron transfer layer,reduce the Schotky barrier of Ti-Fe₂O₃/FTO interface,promote more photogenerated electron of Ti-Fe₂O₃ photoanode to FTO substrate.Although the photocurrent density of W-TiO₂/Ti-Fe₂O₃ photoanode increased by one times,the onset potential had a negative shift of 140 mV.2.The study on the effect of the introduction of WO₃ electron transfer layer on photogenerated charge behavior and PEC properties of Ti-Fe₂O₃ photoanode:To further improve the PEC performance of Ti-Fe₂O₃ photoanode,we introduce WO₃ electron transfer layer between Ti-Fe₂O₃ photoanode and FTO substrate,which has higher carrier mobility and matches the energy band structure with Ti-Fe₂O₃ photoanode.The results show that the introduction of WO₃ electron transfer layer can effectively reduce the resistance of photogenerated electron from Ti-Fe₂O₃ photoanode to FTO substrate,reduce the bulk recombination of photogenerated charge of Ti-Fe₂O₃ photoanode,improve the photogenerated charge separation efficiency of Ti-Fe₂O₃ photoanode.With the help of electron transfer layer,the photocurrent density of WO₃/Ti-Fe₂O₃ composite photoanode increased about four times at 1.23 V vs.RHE,reached 2.15 mA/cm².