Abstract
The oxygen reduction reaction (ORR) is the most important reaction in life processes and in energy transformation. The following work presents the design of a new electrode which is composed by deposited cobalt octaethylporphyrin onto glassy carbon and graphene, where both carbonaceous materials have been electrochemically oxidized prior to the porphyrin deposition. The novel generated system is stable and has an electrocatalytic effect towards the oxygen reduction reaction, as a result of the significant overpotential shift in comparison to the unmodified electrode and to the electrodes used as target. Kinetic studies corroborate that the system is capable of reducing molecular oxygen via four electrons, with a Tafel slope value of 60 mV per decade. The systems were morphologically characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) Electrochemical impedance spectroscopy studies showed that the electrode previously oxidized and modified with cobalt porphyrin is the system that possesses lower resistance to charge transfer and higher capacitance.
Highlights
The oxygen reduction reaction (ORR) is determinant for the operation of devices associated with the conversion and storage of energy, such as fuel cells and metal–air batteries, among others [1,2,3,4,5].In this sense, the development of electrocatalysts for ORR becomes crucial both for the use and commercialization of these technologies [6]
In order to studyStudies the systems in terms of morphology, scanning electron microscopy (SEM) studies were conducted for the glassy carbon (GC), 2.1
In order to study the systems in terms of morphology, SEM studies were conducted for the GC, corresponding to these studies
Summary
The oxygen reduction reaction (ORR) is determinant for the operation of devices associated with the conversion and storage of energy, such as fuel cells and metal–air batteries, among others [1,2,3,4,5].In this sense, the development of electrocatalysts for ORR becomes crucial both for the use and commercialization of these technologies [6]. The oxygen reduction reaction (ORR) is determinant for the operation of devices associated with the conversion and storage of energy, such as fuel cells and metal–air batteries, among others [1,2,3,4,5]. The feasibility of generating low-cost electrocatalysts to reduce molecular oxygen at low overpotentials has been demonstrated This has proved that carbon-based materials, such as activated carbon (carbon black), carbon nanotubes, carbon nanofibers, and graphene, among others, play an important role in overcoming challenges concerning technology, energy, and practical applications.
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