2H-5,10,15,20-tetrakis(3-aminophenyl)porphyrin films: Electrochemical formation and catalyst property testing

Abstract

• Tetra(3-aminophenyl)porphyrin films were formed via superoxide-assisted method; • Ab initio applies for adsorption energy analysis on the catalytic site; • 3-aminophenyl porphyrin based films show promising ORR activity; • Calculations indicate on the same ORR mechanism as experiments. Polymer films based on 2H-5,10,15,20-tetrakis( 3 -aminophenyl)porphyrin have been successfully prepared by superoxide-assisted electrochemical deposition method from dimethyl sulfoxide solutions. Investigation of the deposition process and obtained films demonstrates typical for superoxide-assisted method mechanism of polymer formation, which leads to phenazine type bridges between porphyrin moieties. The density functional theory method has been used to model a polymer chain fragment and an analysis of natural bond orbital has been carried out. According to the calculations, the charge density distribution on the carbon skeleton of the obtained polymer resembles the distribution of charges on carbon materials doped with nitrogen, which are considered as promising catalysts for the oxygen electroreduction. Thus, the energy of adsorption of O 2 and OOH species (intermediates of oxygen electroreduction) on potential catalytic centers of the model polymer fragment has been calculated. The calculation results indicate predominantly two-electron pathway of O 2 reduction. A catalytic activity of poly-2H-5,10,15,20-tetrakis( 3 -aminophenyl)porphyrin films has been shown for the oxygen electroreduction reaction in an aqueous alkaline medium