Enhanced Electro-catalytic Activity of Nitrogen-doped Reduced Graphene Oxide Supported PdCu Nanoparticles for Formic Acid Electro-oxidation

Successful commercialization of direct formic acid fuel cells (DFAFCs) is restricted because of its apparent instability in acidic medium and high cost of typically noble metal based anode catalyst. To adequately address these key issues, in this work, a series of palladium-copper alloy catalyst supported on nitrogen-doped reduced graphene oxide (N-rGO) were synthesized via wet chemical reduction process. Several microscopic and spectroscopic techniques were employed to determine the crystal pattern, particle size, composition and morphology of the synthesized material. Electro-catalytic performance of the synthesized catalysts was carefully verified with respect to formic acid oxidation. All N-doped reduced graphene oxide (N-rGO) supported catalyst show enhanced catalytic activity in comparison to commercial Pd/C catalyst. Electrochemical study reveals precisely that Pd75Cu25/N-rGO catalysts have highest electro catalytic activity 1738 mA mg(pd)(-1) among all synthesized catalyst which is 3.67 times higher than commercial Pd/C catalyst. Pd75Cu25/N-rGO catalyst show lowest Tafel slope (119 mV dec(-1)) and excellent stability after 250 potential cycles. These extensive studies signify that N-rGO support material can remarkably improve the catalytic activity and stability of the catalysts which may be due to outstanding electron transfer capability and synergy between PdCu metallic and N-rGO support. This work helps further design of alloy nanoparticles on N-rGO support as a highly active and stable catalyst for application in the fuel cell. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.