Kinetic Study of the Oxygen Reduction Reaction on Conductive Polymer Electrodes Decorated with ZIF-8 as an O2 Pre-concentrator

FEDERICO C. D. LÓPEZ; MATÍAS RAFTI; WALDEMAR A. MARMISOLLÉ; OMAR AZZARONI; KLAUSS KERN; DORIS GRUMELLI

Belgrado

Congreso; 71th Annual meeting of the International Society of Electrochemistry; 2020

International Society of Electrochemistry

The oxygen reduction reaction (ORR) is one of the most studied in electrochemistry due to its participationin energy conversion devices. Its slow kinetics leads to the inevitable use of catalysts. Within this context, considerable attention was dedicated to electrocatalysis at conducting polymers (CPs) electrodes, its high conductivity and chemical stability makes them very suitable for electrocatalysis purposes [1]. An example of them is CP poly(3-aminobenzylamine-co-aniline) (PABA), copolymer of aniline (ANI), an ORR catalyst, and 3-aminobenzylamine (ABA), which allows the catalysis to occur at neutral pH. One way forincreasing the efficiency of these catalysts is the pre-concentration of the O2 reagent on the surface of the electrode. To achieve that, organometallic networks (MOF) are used as a novel three-dimensional microporous architecture. In particular, the MOF ZIF-8 (Zeolitic Imidazolate Frame), obtained via the polymeric reaction between Zn(NO3).6H2O and 2-methyl-imidazole, is widely employed as an O2 preconcentrator at the electrocatalytic interface.On the other hand, aniline polymer (PANI) is known to reduce O2 through the formation of H2O2 in a twoelectron process [2] but nothing is specifically known about the O2 reduction mechanism in PABA.Meanwhile, the path of the O2 molecule through the pores of the ZIF-8 is more turbulent than in solution, being able to modify the kinetics of the conductive polymer. In this work we will present the development of an electrode composed of the PABA film decorated with ZIF-8 crystals and results from rotating disk electrode (RDE) experiments, performed in order to model the kinetics of the system