Electrocatalytic Reduction of Oxygen at Perovskite (BSCF)-MWCNT Composite Electrodes

Farhanini Yusoff,Azizan Aziz,Norita Mohamed,Sulaiman Ab Ghani

doi:10.4236/msa.2014.54025

Abstract

A composite paste electrode based on Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF)—initially synthesized by solgel method—and multiwall carbon nanotube (MWCNT) as a cathode in fuel cells is developed. The composite pastes are prepared by the direct mixing of BSCF:MWCNT at 90:10, 80:20 and 70:30 (% w/W). These electrodes are then characterized by the x-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm, electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The XRD and SEM confirm the inclusion and the uniform dispersal of the MWCNT within BSCF, respectively. The nitrogen adsorption isotherm study shows that the porosity of the composite paste electrode has been improved by two-fold from the BSCF electrode. The EIS and CV demonstrate that the higher ratios of MWCNT in the composites are critical in improving the electronic conductivity as well as the kinetics. It is also noticeable that the electrode has increased the catalysis of oxygen in 0.1 M KOH (pH 12.0). Cyclic voltammetric studies on the oxygen reduction reaction (ORR) suggest that the incorporation of MWCNT is vital in improving the electrode (cathode) properties of a fuel cell.

Highlights

The oxygen reduction reaction (ORR) is important in variety of electrochemical processes including corrosion inhibition and metal-air batteries, the application of the ORR in fuel cells is of particular interestHow to cite this paper: Yusoff, F., et al (2014) Electrocatalytic Reduction of Oxygen at Perovskite (BSCF)-multiwall carbon nanotube (MWCNT) Composite Electrodes
The electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) demonstrate that the higher ratios of MWCNT in the composites are critical in improving the electronic conductivity as well as the kinetics
The structural characteristics of the as-prepared BSCF-MWCNT composite have been examined via x-ray diffraction (XRD) (Figure 1)

Summary

Introduction

The oxygen reduction reaction (ORR) is important in variety of electrochemical processes including corrosion inhibition and metal-air batteries, the application of the ORR in fuel cells is of particular interestHow to cite this paper: Yusoff, F., et al (2014) Electrocatalytic Reduction of Oxygen at Perovskite (BSCF)-MWCNT Composite Electrodes. The oxygen reduction reaction (ORR) is important in variety of electrochemical processes including corrosion inhibition and metal-air batteries, the application of the ORR in fuel cells is of particular interest. The electrode process may involve either 2 or 4 electrons depending on the electrode material used [11]-[14]. This reaction, requires the use of platinum as the catalyst, which contributes to the high cost of these fuel cells. By improving its electronic properties, the perovskite materials can be used as catalyst for low temperature fuel cell and metal air-batteries [19] [20]

Methods

Results

Conclusion