Electrocatalysis And Electrochemical Sensing Of Functionalized Metalloporphyrin Porous Material

Porphyrin often exists widely in nature in the form of metal complexes,and it is a functional molecule necessary for animal and plant life.Due to its unique electronic and optical properties,porphyrin has a wide range of applications in biomimetic catalysis and sensing.Porphyrin-based metal-organic porous materials are porous framework materials formed by metal ions and porphyrin organic ligands,which inherit the rigid planar structure and unique physical and chemical properties of porphyrin and the porosity,large specific surface area and tunable pore structure,it further broadens the application range.In this paper,metalloporphyrin aerogel and porphyrin metal-organic framework materials were synthesized by using porphyrin ligands as precursors,and their applications in electrocatalytic oxygen reduction reaction and electrochemical dissolved oxygen sensing were studied in detail,respectively.The development of a new type of porphyrin-based porous material catalyst provides the experimental basis and theoretical basis.The main research contents are as follows:1.Metalloporphyrin aerogel-derived Fe-N-C catalyst for oxygen reduction.Firstly,a porous metalloporphyrin aerogel material,Al-TCPP aerogel was synthesized by hydrothermal method with iron porphyrin ligands and Al（III）ions as nitrogen source and carbon source,and then supercritical CO₂drying method was used to retain the porous structure.Furthermore,through high-temperature carbonization,the active sites are exposed,and the porous Fe-N-C catalyst is obtained.The catalyst can catalyze the oxygen reduction reaction in alkaline electrolyte and exhibits superior catalytic performance than pure Fe-TCPP ligands and Al-TCPP MOF,due to the porous structure of the aerogel,it can expose more catalytic site,which is favorable for mass transfer in catalytic reactions.The electron transfer process is an ideal four-electron reduction process,and the Al-TCPP aerogel catalyst exhibits good stability and methanol tolerance.These results indicate that the porphyrin gel-based catalytic material has potential application prospects,which can be used for the following applications and provides ideas for the design of electrocatalyst materials.2.Dissolved oxygen detection based on ratiometric electrochemical sensing of PCN-222（Fe）supported ferrocene.Ferrocene groups were loaded into porphyrin MOFs PCN-222（Fe）by solvent-assisted ligand incorporation to synthesize nanoscale composite Fc@PCN-222（Fe）with two redox centers.Firstly,the size of PCN-222（Fe）particles was adjusted by changing the addition amount of dichloroacetic acid to obtain nano-scale PCN-222（Fe）,which was further functionalized to obtain Fc@PCN-222（Fe）.The Fc group and Fe-porphyrin were used as an internal reference signal and DO indicator in the Fc@PCN-222（Fe）composite to construct a ratiometric sensing system for the detection of dissolved oxygen in solution.During the detection process,the composite showed high stability and high selectivity.In addition,the preparation process of this ratiometric electrochemical sensing system is simple and has potential application value in the detection of dissolved oxygen.