Pd-MnO2-Fe2O3/C as electrocatalyst for the formic acid electrooxidation

Abstract

Pd-MnO2-Fe2O3/C and Pd/C (for comparison to the former) were synthesized by NaBH4 reduction method and then annealed at 500 degrees C. The catalysts were characterized physically by various techniques including XRD, TEM, EDX, XPS and ICP. The results showed that both MnO2 and Fe2O3 are in the amorphous form while Pd is crystalline for both catalysts. The particle size of Pd nanoparticles in Pd-MnO2-Fe2O3/C and Pd/C catalysts were found to be 11.6 nm and 10.9 nm, respectively. The total metal weight percent in Pd-MnO2-Fe2O3/C was determined as 18% and the metal molar ratios of Pd:Mn:Fe was calculated as 49:20:31. By cyclic voltammetry (CV) and chronoamperometry (CA), the ternary catalyst showed a superior electrocatalytic activity, namely of approximate to 3.4 times higher than Pd/C. The results also indicated that amorphous third parties may play a crucial role to improve the catalyst activity towards formic acid oxidation. All of these results are reported and discussed in details herein. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.