Preparation And Optical Properties Of CeO₂/TiO₂ Heterojunction

Nowadays,the rapid development of human civilization and the sustainable cycle of natural environment have shown an unbalanced situation.The problems of energy and environmental pollution are like two big mountains,which lie on the only way of development.Many problems,such as the development of new energy,the treatment of environmental pollution,the pollution of heavy metals in soil and the shortage of water resources,have become inevitable challenges for human beings.In the process of many scientists trying their best to explore solutions,Ti O₂has the advantages of high activity,low cost,non-toxic,high chemical stability,and its application prospect is optimistic by the majority of researchers.In this paper,anatase Ti O₂was chosen as the research object because of its catalytic ability.The main results and conclusions are as follows:1.Firstly,Ti O₂powder was prepared by hydrothermal method from titanium source.On the basis of this,the CeO₂/TiO₂heterojunction composed of two n-type semiconductor materials Ce O₂and Ti O₂was obtained by adding cerium source.The morphology and structure of the samples were characterized and analyzed by SEM.The results show that:1)compared with water purification,the specific surface area of CeO₂/TiO₂heterojunction produced by ethanol purification is significantly increased,and the distribution is more uniform and smooth;2)In the ratio of 100:3 and 10:3,100:3 can ensure a good specific surface area,while too much cerium will have a negative effect.2.Secondly,on the basis of density functional theory,the CeO₂/TiO₂heterojunction was observed under scanning electron microscope（SEM）,and the molecular design of CeO₂/TiO₂heterojunction was carried out scientifically and reasonably.The theoretical calculation model was built,and the energy band diagram and density of state diagram of the heterojunction were calculated.1)The energy band diagram and the density of state diagram are the same,which can be verified by each other;2)Compared with pure Ti O₂,the band gap of CeO₂/TiO₂heterojunction is significantly smaller than that of pure Ti O₂（theoretical calculation value 3.061 e V）,3)Based on the above,the influence of heterojunction structure on Ti O₂is discussed.3.Furthermore,the optical properties of CeO₂/TiO₂heterostructure are calculated.1)Through the calculation of the spectrum absorption diagram,it is found that the light response range has changed and the red shift has occurred.The CeO₂/TiO₂heterojunction structure can broaden the light absorption range from the ultraviolet region to the visible region,so the optical properties of the material have been effectively improved.2)According to the above,the reason for the improvement of light absorption capacity is discussed:the narrow band gap can effectively reduce the energy needed to excite photons and improve the light absorption capacity.