Preparation Of Sulfide/BiOBr Hybrid Materials And Their Photocatalytic Performance

Photocatalysis technique is regarded as an important method to solve the energy crisis and environmental problem.As a kind of new photocatalytic materials,BiOBr materials has attracted more and more attention in recent years.The band gap of BiOBr?².7 eV?ensures the absorption of visible light,and the[Bi₂O₂]²⁺layered structure improves the separation of photoelectrons and holes.However,the photocatalytic ability of pure BiOBr cannot afford the further application,the band gap of BiOBr can be adjusted to be more suitable for photocatalysis?1.5 eV?,and the recombination of photoelectrons and holes is high.In this thesis,heterojunction structure has been constructed between sulfides?SnIn₄S₈,NiS and ZnIn₂S₄?and BiOBr using two-step hydrothermal method.The rearranged band structure will improve the light absorption,the sulfides with good conductivity will help to improve the charge transfer and the heterojunction structure will contribute to the improvement of carrier separation efficiency.Finally,photocatalytic activity will be enhanced.The main research contents are as following:?1?Synthesis of SnIn₄S₈/BiOBr hybrid nanomaterials and their photocatalytic performance.SnIn₄S₈/BiOBr hybrid materials has been successfully synthesized through a two-step hydrothermal method.The influence of SnIn₄S₈ on phase,morphology,spectrum response,interfacial impedance,photoluminance,transient photocurrent and photocatalytic performance has been studied.The results showed that SnIn₄S₈ markedly enhanced the photocatalytic activity of BiOBr.The sample with 0.2 at.%SnIn₄S₈ exhibited the best photocatalytic ability,the degradation ratio of RhB reached 99.84%within 40 min,while it was only 72.04%for pure BiOBr.The best photocatalytic activity was 5.35 times higher than pure BiOBr,which was mainly because of the improvement of photoelectrons separation and charge transfer.?2?Synthesis of NiS/BiOBr hybrid nanomaterials and their photocatalytic performance.NiS/BiOBr hybrid materials has been synthesized through a two-step hydrothermal method.The influence of NiS on morphology,phase,spectrum response,interfacial impedance,photoluminance,transient photocurrent and photocatalytic performance has been studied in detail.The results showed that NiS markedly enhanced the photocatalytic activity of BiOBr.The sample with 0.2 at.%NiS exhibited the best photocatalytic ability,the degradation ration of RhB reached 99.5%within 50 min,while it was only 84.0%for pure BiOBr.The best photocatalytic ability of hybrid sample was 2.5 times higher than pure BiOBr,which is mainly due to the decrease of carrier recombination rate.?3?Synthesis of ZnIn₂S₄/BiOBr hybrid nanomaterials and their and photocatalytic performance.ZnIn₂S₄/BiOBr hybrid materials has been synthesized through a two-step hydrothermal method.The influence of ZnIn₂S₄ on morphology,phase,spectrum response and photocatalytic performance has been studied.ZnIn₂S₄markedly enhanced the photocatalytic ability of BiOBr.The sample with 0.2 at.%NiS exhibited the best photocatalytic ability,the degradation ratio of RhB reached98.21%within 60 min,while it was only 69.12%for pure BiOBr.The best photocatalytic ability was 4.75 times higher than pure BiOBr.