Study On The Photocatalysis Of Organic-inorganic Hybrid Lead Halide Perovskite For The Selective Oxidation Of Cyclohexane

Cyclohexanol and cyclohexanone（KA oil）,the partial liquid-phase oxidation products of cyclohexane,are important raw materials for the production of polyamide products.Compared with the preparation of Ka oil by thermal catalysis in industry,photocatalysis is a green,energy-saving and mild emerging technology.Organic-inorganic hybrid lead halide perovskite has the characteristics of high absorption coefficient,adjustable band gap and high electron/hole mobility.It has broad prospects in the field of photocatalysis.The key of this paper is to improve the carrier life and stability of perovskite materials.In this paper,a series of（BA:MA）Pb Br₃ perovskite compounds were prepared by adjusting the molar ratio of methylamine cation（CH₃NH₃⁺,MA⁺）and n-butylamine cation（CH₃CH₂CH₂CH₂NH₃⁺,BA⁺）by solvothermal method.Then,the effects of different crystal structure,micro morphology and optical properties on the visible photocatalytic oxidation of cyclohexane were investigated,and the photocatalytic mechanism was discussed.Physical property analysis and catalytic study show that when the molar ratio of MA⁺and BA⁺is 5:4,（BA:MA）Pb Br₃ has appropriate redox position（conduction band value is-1.01 e V,valence band value is 1.31 e V）and high electron hole separation efficiency,which is conducive to photocatalytic reaction.In order to further improve the photocatalytic cyclohexane oxidation conversion of（BA:MA）Pb Br₃ material,a series of（BA:MA）Pb Br₃/P25-x complexes were obtained by compounding it with different amounts of titanium dioxide（P25）.The effects of the introduction of P25 on the phase structure,optical properties,carrier separation and photocatalytic performance of（BA:MA）Pb Br₃ were investigated.Among them,the cyclohexane conversion of（BA:MA）Pb Br₃/P25-100 reached 0.74%.This is attributed to the highest visible light absorption and lower electron-hole recombination efficiency of（BA:MA）Pb Br₃/P25-100 with heterojunction structure.Finally,in order to improve the stability of perovskite materials,the ternary（BA:MA）Pb Br₃/CN/P25-x composite was successfully prepared by introducing g-C₃N₄（CN）.Its high crystallinity and N-Br bond interaction not only improve the charge separation and transport efficiency,but also reduce defects and effectively improve the catalytic activity and stability of（BA:MA）Pb Br₃/g-C₃N₄/P25-x.This study is the first to explore the application of hybrid perovskite materials as photocatalysts in photocatalytic cyclohexane oxidation,which has important basic research significance and practical application value.