Electrochemical properties of air electrodes based on MnO2 catalysts supported on binary carbons

An alkaline air electrode with a ball-milled gamma-MnO2 catalyst was prepared and studied. The electrochemical performance of air electrode composed of MnO2 supported on CNT/BP2000 (1: 1) two carbons for oxygen reduction reaction (ORR) was investigated by using the linear polarization method, Tafel analysis, galvanostatic discharge method, and AC impedance spectroscopy. The surface morphologies of CNT and the active layer of the air electrode were also investigated by SEM. Experimental results indicated that air electrodes with MnO2 supported on CNT and BP2000 carbons showed excellent electrochemical properties. A multiple spray technique was used to prepare the air electrode. The amount of loading of catalyst carbon slurry (MnO2 supported on CNT/BP2000 binary carbons) on the active layer varied from 0.60 to 3.63 mg/cm(2). The electrochemical performance of air electrodes with MnO2 catalyst and with two catalysts of KMnO4 and MnO2 was compared and discussed. The air electrode with a low-cost MnO2 catalyst shows a highly potential candidate for application on metal-air battery or micro-fuel cell. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.