Synthesis,Characterization And Catalytic Performance Of A Novel Three-dimensional Hierarchically Porous Zirconium Phosphonate ZrDP

Zirconium phosphonates are a kind of porous materials synthesized by replacing inorganic phosphates with organic phosphonates on the basis of zirconium phosphates.Compared with zirconium phosphates,zirconium phosphonates have more flexibility in the design and structural control of their molecules due to the diversity of organic phosphonates.In recent years,zirconium phosphonate materials have significant application value in the field of catalysis due to their highly designable functionality and structural stability.Both of them can be used as catalysts and catalyst supports,and have shown good prospects for application.In this thesis,a novel multilevel porous organic zirconium phosphonate material（named ZrDP）was synthesized using multi-nitrogen heterocyclic phosphonates.It was found that ZrDP had a large specific surface area and pore volume,and the strong coordinating nitrogen heterocyclic base in its structure made it the potential to be an excellent catalyst support.Using ZrDP as the main material,this thesis achieved coordination loading of transition metal ions(Cu²⁺,Fe³⁺,Co²⁺)with ZrDP,and prepared a series of catalysts（Cu@ZrDP,Fe@ZrDP,Co@ZrDP）,which were used in the selective oxidation of benzyl alcohol reaction.ZIS/ZDP composite catalyst was prepared with ZrDP as the carrier of the semiconductor Zn In₂S₄and used in the photocatalytic degradation of organic dyes.The specific content is as follows:1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylene phosphonic acid（DOTMP）was synthesized and used as a raw material with zirconium oxychloride to synthesize a novel three-dimensional phosphonate zirconium（ZrDP）with multilevel porous by hydrothermal method.Scanning electron microscopy showed that ZrDP was an irregular spherical structure composed of many small leaflets,with many pores of approximately 0.64 nm and 1.68nm in diameter on the leaflets,and the stacking of the leaflets produced mesopores and macropores of about 30-50 nm.By impregnating the transition metal ions into the nitrogen heterocycles,composite catalysts（Cu@ZrDP,Fe@ZrDP,Co@ZrDP）were prepared.Among them,Cu@ZrDP showed higher catalytic activity due to more metal active sites loaded on the carrier,with a conversion rate of benzyl alcohol of 67.7%and a yield of benzaldehyde of 61.1%after 8 hours of reaction with air as the oxidant,and maintained good catalytic performance after five cycles.In this reaction,ZrDP not only served as a carrier to disperse and fix the catalytic active site,but also exhibited some catalytic activity,playing an auxiliary catalytic role.In addition,the author used ZrDP as the carrier,In³⁺and Zn²⁺were loaded,and then using thioacetamide as the sulfur source,the ZIS/ZDP composite catalyst was prepared by in-situ growth method.The degradation performance of the composite catalyst under visible light in Rhodamine B（Rh B）solution was system-atically studied.It was found that the composite catalyst ZIS/ZDP-2 showed good performance in the photocatalytic degradation of Rh B,with a degradation rate of Rh B of 99.01%.After four cycles,the catalytic degradation rate of Rh B remained at 98.69%.The ZIS/ZDP-2 composite catalyst also showed good degradation performance for methylene blue and malachite green cationic dyes.