Study On The Photocatalytic Performance Of TiO₂/MoS₂ Heterojunction Nanomaterials

With the rapid development,energy material is an essential for social development.However,traditional energy is not adapted to modern development.In 1972,Japanese researchers found that semiconductors could produce hydrogen by photocatalytic.And this discovery has been widely concerned then.It has received much attention as a promising photocatalytic semiconductor due to its excellent functionality.Semiconductor photocatalystic,such as TiO₂,exhibit high photocatalytic performance.However,it can only use a little of solar energy for wide band gap.Hence,it is very necessary to adopt some means to improve the photocatalytic efficiency of TiO₂ semiconductors.In this thesis,the heterostructure method to improve the photocatalytic efficiency.The related properties of TiO₂ anatase,monolayer MoS₂ and TiO₂/MoS₂ were calculated theoretically by hybrid functional?HSE06?method.It was found that the band gap of the composite system reduced to 1.38 eV.And the optical properties of the composite system have been improved over that of the pure TiO₂ anatase,which is an expected result.At the same time,we studied the effect of pressure on the properties of TiO₂/MoS₂ heterojunction.The calculation results show that the photocatalytic performance of the material is improved with the increase of pressure.The effects of Cu and N doping on the surface properties of TiO₂ anatase and the heterojunction of TiO₂/MoS₂ were investigated.The calculation results show that?Cu,N?co-doping can effectively improve the photocatalytic hydrogen production performance of the material.In addition,the effects of the spacing of TiO₂ and MoS₂ layers on the properties of the composite system were studied.The results show that the optical properties of the system can get best when the composite material is at a moderate spacing.Based on the composite system,the effect of the numbers of MoS₂layers have been studied on the performance.The results show that a reasonable increase of MoS₂ layers in the appropriate range can improve the optical performance of the conforming system.In this paper,the theoretical calculation of the related properties of TiO₂ rutile,monolayer MoS₂ and TiO₂/MoS₂ is performed by the orbital functional?LDA+U?method.It is calculated that the band gap for the single layer MoS₂ and TiO₂rutile composite system of 1.22 eV.And the optical properties of the composite system are improved compared with the pure TiO₂ rutile.These results confirm that the MoS₂cocatalyst can effectively reduce the TiO₂ band gap and increase its optical performance,and enhance the ability of photocatalytic.