Preparation Of POSS-Based Multifunctional Materials Functionalized With Porphyrins And Research On Photocatalytic Applications

With the explosive development of industry and technology,energy shortage and environmental degradation have become two intractable global problems,and researchers are working to develop new materials to solve these problems in order to mitigate their harmful effects on humans and nature.Porous photocatalysts have received much attention due to their rich specific surface area and pore structure and their potential photocatalytic activity,in which the pores can achieve efficient adsorption and diffusion,enhance light capture,and provide abundant active sites.Porous photocatalysts are promising materials capable of both adsorption and oxidation/reduction of target substances and show great potential for environmental remediation and energy production.In this thesis,firstly,octaethylsesquioxane（OVS）was used as the basic raw material to explore the preparation of hybrid porous polymers using FriedelCrafts reaction and tetraphenylporphyrin for cross-linking;secondly,octaaminopropyl sesquioxane（OAS）was used as the basic raw material to explore the preparation of porphyrins bridged by amide bonds using amide condensation reaction and tetrakis（4carboxyphenyl）porphyrin（HCPP）for cross-linking.These porphyrin-functionalized POSSbased hybrid porous polymers（PCS-CA）were investigated.These porphyrin-functionalized POSS-based porous polymers were also investigated for photocatalytic and adsorption applications.1.Two porphyrin-functionalized POSS-based hybrid porous polymers（PCSH,PCSM）were successfully prepared by Friedel-Crafts reaction using tetraphenylporphyrin（HTPP）and its derivative manganese-based tetraphenylporphyrin（MnTPP）with octavinylsesquioxane（OVS）as the building blocks.FTIR solid-state NMR,and X-ray photoelectron spectroscopy demonstrate the successful preparation of the materials,and BET,SEM,and PXRD prove that PCSH and PCSM are amorphous porous materials.We exploited the high specific surface area of PCSH and PCSM and the good photoelectric properties of porphyrin units to catalyze styrene to styrene oxide,and explored the optimal reaction conditions.Under the optimal reaction conditions,the conversion of styrene was able to reach 99.9%and the yield of styrene oxide reached 86.7%.PCSs have excellent cycling performance and can be catalyzed more than 5 times.In addition,we proposed a possible catalytic mechanism based on the experimental results and previous work reported.2.We chose tetra（4-carboxyphenyl）porphyrin（HCPP）and octamethylsesquioxane（OAS）to generate porphyrin-functionalized POSS-based hybrid porous polymers（PCS-CA）bridged by amide bond condensation,and demonstrated the successful synthesis of porous polymers by FTIR spectroscopy and solid-state NMR.The specific surface area and pore structure of PCSCA were probed by N₂ adsorption-desorption tests,and the morphological characteristics of the porous material were characterized by PXRD and SEM,which proved that the polymer is amorphous,and the TGA results indicated that it has excellent thermal stability.Based on the porous structure and optoelectronic properties of PCS-CA,we investigated the adsorption of heavy metal ions by PCS-CA,and the maximum adsorption amounts of Mn²⁺,Hg²⁺,Cu²⁺ and Pb²⁺ were 188.6 mg g-1,102.5 mg g-1,66.8 mg g^-1 and 41.4 mg g^-1,respectively.The adsorbed Mn²⁺ porous material PCS-CA-Mn has excellent photocatalytic performance,and the degradation efficiency of Congo red and methyl orange dyes reached 99%under solar illumination,and the PCS-CA-Mn has good recyclability for the degradation of dyes and still has excellent photodegradation ability after eight cycles.The excellent photocatalytic ability of PCS-CA-Mn was further demonstrated by photoelectric property tests and a possible catalytic mechanism was proposed.