Research On Photoanode Of ?-Fe₂O₃ Nanorode Array And Photoelectrochemical Properties

The increasingly serious environmental pollution and energy shortage prompt people to seek a clean energy which can replace the traditional energy.Hydrogen is believed a kind of clean energy source,since its combustion product is water,without pollution to the environment.Hydrogen production by photolysis of water is an important method for hydrogen production,but its efficiency is very low.It is a process jointly determined by thermodynamics and dynamics,so we need to study from these two aspects.Since not all semiconductor materials meet the requirements of photoelectrolysis,we need to find suitable semiconductor materials,especially those that can respond to visible light and have high efficiency of photocatalysis,so as to overcome the problem of low energy conversion efficiency in photoelectrolysis of water to hydrogen production.Hematite has the advantages of suitable band gap width,low cost,non-toxicity and good stability,so it is a good material for photoanode,but it also has the disadvantages of poor conductivity,short diffusion length,slow oxygen evolution kinetics and so on.In this dissertation,we used ?-Fe₂O₃ as the base material,through high temperature annealing,ion doping and construction of heterojunction,the photogenic carrier recombination rate of ?-Fe₂O₃ was inhibited,and its separation efficiency was improved,so as to improve the photocurrent density.The main research contents of this paper are as follows:1)The ?-Fe₂O₃ nanorods was prepared and synthesized by hydrothermal method,and ?-Fe₂O₃ was annealed at high temperature.In addition,the basis of FTO was replaced with Ti piece,and different amounts of Co were doped in ?-Fe₂O₃/Ti to explore the influence of different amounts of Co doping on the photocurrent density of ?-Fe₂O₃.Finally,we tried to deal with the Co and Ni doping of ?-Fe₂O₃/FTO.These treatments increase the photocurrent density of the photoanode.2)Through ?-Fe₂O₃ drops with CQD,we constructed ?-Fe₂O₃/CQD heterojunction photoanode,at the same time constructed Co-Fe₂O₃/CQD heterojunction photoanode by using the Co-Fe₂O₃ and CQD.Under illumination of AM 1.5G?the power density is 100 m W/cm2?,the photocurrent density of ?-Fe₂O₃/CQD increases with the increase of CQD load,within a certain range of CQD load.At 1.23 VRHE,the photocurrent density of ?-Fe₂O₃/CQD is 2.09 m A/cm2,the photocurrent density of Co-Fe₂O₃/CQD is 2.43 m A/cm2.3)The ?-Fe₂O₃/WO3 and WO3/?-Fe₂O₃ heterojunction photoanodes were successfully constructed by hydrothermal synthesis.The results showed that the photocurrent density of the heterojunction photoanodes constructed by us was significantly improved.Under the illumination of AM 1.5G?the power density is 100 m W cm-2?,the photocurrent density of ?-Fe₂O₃/WO3 at 1.23 VRHE was 1.40 m A /cm2,and that of WO3/?-Fe₂O₃ was 1.99 m A/cm².