Doped Graphene as Non-Metallic Catalyst for Fuel Cells

Adriana Marinoiu,Mircea Raceanu,Mihai Varlam,Amalia Soare,Elena Carcadea,Ioan Stefanescu

doi:10.5755/j01.ms.23.2.16216

Abstract

Aiming a commercial development of proton exchange membrane fuel cells (PEMFC), a low cost, sustainable and high performance electrocatalyst for oxygen reduction reaction (ORR) with capability to replace/reduce rare metals, are high desirable. In this paper, we present a class of doped graphene, namely iodinated graphene with highly ORR electrochemical performances, synthesized by using the electrophilic substitution method. The prepared samples were characterized by different techniques, including Scanning Electron Microscopy SEM, X-ray photoelectron spectroscopy XPS, Raman spectroscopy, surface area measurement by BET method, that revealed the structure and morphology. The most highly iodinated graphene was tested in a single cell by measuring the cyclic voltammetry. The electrochemical performances were evaluated and compared with a typical PEMFC configuration, when a single cathodic peak at 0.2 V with a current density of – 3.67 mA cm-2 for the Pt/C electrode was obtained. The best electrochemical performances in terms of electrochemical active area, was obtained for a new concept of cathode composed from Pt/C – iodine doped graphene, when a well-defined peak centred at 0.23 V with a current density of approx. – 9.1 mA cm-2 was obtained, indicating a high catalytic activity for ORR.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.16216

Highlights

Proton exchange membrane fuel cells (PEMFCs) have attracted a considerable attention as clean and efficient power sources
In this study we will use the previous protocol that we developed for synthesis of graphene base materials [25] in order to prepare iodine doped graphenes (IDG), followed by their testing and validation as base materials for FC electrodes
Iodine-doped graphenes have been successfully obtained by a simple and low cost strategy based on electrophilic substitution

Summary

INTRODUCTION

Proton exchange membrane fuel cells (PEMFCs) have attracted a considerable attention as clean and efficient power sources. There is an important trend to replace the Pt-based oxygen reduction reaction (ORR) electrocatalysts with metal-free electrocatalysts having high catalytic activity and durability in a sustainable effort to diminish the FC production cost and allow this technology to become approachable for commercialization [1 – 4]. Graphenes doped with heteroatom, such as boron (B), halogen (Cl, Br, I), nitrogen (N), phosphorus (P), sulphur (S), and their mixtures, have attracted attentions as metal-free ORR electrocatalysts, based on different electronegativity between the heteroatom dopants [9 – 16]. We hypothesize that the ORR activity could be improved due to electrocatalytic efficiency of iodine doping, facilitated by forming charge transfer complexes of I3- and I5-, which enhance the doping capability and graphene work function [16, 17]. Due to the fact that the experimental information connected to the electrochemical science and technology of ORR for iodinated graphenes is not yet well explained, any achievements regarding these electrocatalytic systems providing good ORR performances could be primary importance

EXPERIMENTAL

RESULTS AND DISCUSSION

CONCLUSIONS