Controlled Electropolymerization of Porphyrin-Based Materials

Abstract

Porphyrin-based materials have unlocalized p-electrons; additionally, they form complexes through coordinating transition metal ions and can assemble as supramolecular structures. Due to these exceptional properties, they have found widespread applications in optoelectronic devices such as solar energy harvesting systems and photonic materials[1]. Porphyrins have also been used as the building blocks of covalent organic frameworks (COFs). An example of these materials is COF 420. Conjugated Porphyrin polymer and porphyrin-based COF have shown promising performances in electrocatalysis, especially toward oxygen reduction reaction (ORR) and in fuel cells and metal-air batteries [2,3]. In this work, we investigated the parameters, influencing the electropolymerization of tetrakis(4-aminophenyl)porphyrin (TAPP) and cobalt- tetrakis(4-aminophenyl)porphyrin (Co-TAPP) in organic media. The results have shown that the morphology and crystallinity of electrodeposited film are strongly dependent on the experimental conditions such as temperature, electropolymerization rate, electrode surface, and the monomer concentration. Rational adjustment of these parameters enabled us to gain control over the growth of the crystalline domains of pTAPP and p(Co-TAPP) films. Stacking of the porphyrin frameworks via p-p interactions, we explored the possibility of bottom-up synthesis of porphyrin-COF dendrites. We observed a structure-to-function relationship between the ordering of the covalent organic polymers and their electrocatalytic activities in reducing oxygen in alkaline media. Lian, Wenhui, et al. "Synthesis and properties of 5, 10, 15, 20-tetra [4-(3, 5-dioctoxybenzamidephenyl] porphyrin and its metal complexes." Journal of the Serbian Chemical Society3 (2012): 335-348.Day, Nicholas U., and Carl C. Wamser. "Poly-tetrakis-5, 10, 15, 20-(4-aminophenyl) porphyrin Films as Two-Electron Oxygen Reduction Photoelectrocatalysts for the Production of H2O2." The Journal of Physical Chemistry C21 (2017): 11076-11082.Walter, Michael G., and Carl C. Wamser. "Synthesis and characterization of electropolymerized nanostructured aminophenylporphyrin films." The Journal of Physical Chemistry C17 (2010): 7563-7574.