Fabrication and Characterization of Metal‐Free Composite Electrodes Based on Few‐Layer‐Graphene Nanoplatelets for Oxygen Reduction Reaction Applications

Abstract

The fabrication of advanced graphene‐based electrodes is currently an open research topic because of their potential in a broad range of applications, such as in light‐emitting diodes, field‐effect transistors, solar cells, supercapacitors, batteries, electrochemical energy storage, and sensors, which can be traced back to their remarkable electronic, mechanical, optical, and thermal properties. Herein, the fabrication and characterization of metal‐free few layer graphene‐based composite electrodes for oxygen reduction reaction (ORR) applications is reported. Electrodes’ characterization and performance are assessed using Raman spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. The electrocatalytic activity for ORR is elucidated by determination of the reaction onset potential at different pH values. The best formulation shows cathodic peak current density up to −469 μA cm−2, accompanied by the lowest potential peak separation of 0.17 V and the lowest charge transfer resistance of 1657 Ω cm−2, which is almost five times lower if compared with the composite electrode without graphene. The results suggest that similar nanocomposites electrodes might be potentially exploited in life processes such as biological respiration, and in energy converting systems such as fuel cells or microbial fuel cells.