Preparation And Catalytic Desulfurization Performance Of MOFs Wrapped Metallophthalocyanine

With the rapid development of science and technology,environmental pollution and climate problems caused by fossil energy combustion have become the focus of global attention.The new environmental-friendly desulfurization technologies will decrease the environmental pollution and climate problems of high CO₂ emissions from motor vehicles.Moreover,desulfurization technology contributes to realizing the strategic goal"Emission peak and Carbon neutrality".Photocatalytic oxidation desulfurization technology is widely concerned in the fuel desulfurization field due to the advantages of mild conditions and low cost.Noteworthily,the selection of catalysts is the key to oxidative desulfurization technology.Metal phthalocyanines are widely used in photocatalytic technology because of their visible light response and heme-like oxygen loading function.However,the agglomeration problem of phthalocyanine limits its wide application in the field of deep oxidative desulfurization.To overcome the problems,a series of metal phthalocyanines with different central metal ions and different substituents were designed and synthesized.The metal phthalocyanines were further loaded on the surface of metal-organic framework materials（MOFs）with different structures using a solvothermal method.MOFs restrain the agglomeration of metal phthalocyanines and improve photocatalytic desulfurization performance.A biomimetic catalytic system was performed to evaluate the photocatalytic desulfurization performance taking thiophene as the target degradation species and oxygen molecules as the oxidant.The main works are summarized as follows.（1）A series of metal phthalocyanines MPc R₄(R=H,COOH;M=Mn²⁺,Fe²⁺,Co²⁺,Ni²⁺,Cu²⁺,Zn²⁺)with different structures were synthesized by solid-phase melting method.The structure was characterized by elemental analysis,FT-IR and UV-Vis.A biomimetic catalytic system composed of metallophthalocyanines and molecular O₂ were performed to study the degradation of thiophene under natural light and room temperature.The results showed that the desulfurization efficiency of metal phthalocyanines all reached more than 80%after 3 h.The desulfurization rate of carboxyl substituted metal phthalocyanines was better than that of unsubstituted metal phthalocyanines.Specially,the highest desulfurization rate of Cu Tc Pc could reach 92.45%.The results revealed that the conjugate structures and the center metal ion of metallophthalocyanines played critical roles in oxidative desulfurization performance.（2）Metal-organic framework materials（MOFs=ZIF-8（Zn）,MIL-53（Fe）,MIL-53（Al）,MIL-100（Fe）,MIL-100（Cr））with different structures and properties were prepared by the solvothermal method,and their structures were characterized by SEM,XRD,FT-IR,and XPS.The results showed that MOFs were prepared successfully.The adsorption and removal performance of the five MOFs was investigated,taking rhodamine B as the target organic pollutant at room temperature.The results showed that the MIL-53（Al）materials have excellent adsorption activity and the maximum removal rate of rhodamine B reached more than95%.（3）The metal phthalocyanines were loaded on the surface of MIL-53（Al）by the solvothermal method to prepare the metalphthalocyanine/MIL-53（Al）catalysts.The structure and surface morphology were analyzed by SEM,XRD,FT-IR,UV-Vis,XPS and other techniques.A biomimetic catalytic system composed of MTc Pc/MIL-53（Al）and molecular O₂was performed to study the degradation of thiophene under natural light and room temperature.The results showed that the removal rate of thiophene was significantly improved after loading the metal phthalocyanine on the surface of MIL-53（Al）.Considering the MTc Pc/MIL-53（Al）catalysts,the removal rate of thiophene reached more than 97.91%.Among them,the Mn Tc Pc/MIL-53（Al）catalysts have excellent adsorption activity,and the maximum removal rate of thiophene reached 100%after 3 h.Additionally,mechanistic studies revealed that the MOFs/*O₂-MPc R₄⁺species were the central active intermediates in the photocatalytic oxidative desulfurization reaction.The cycling stability experiments showed that the removal rate of thiophene reached 93.01%after 5 cycles.The results indicated that the Mn Tc Pc/MIL-53（Al）catalysts have high cycling stability.