Platinum–TM (TM = Fe, Co) alloy nanoparticles dispersed nitrogen doped (reduced graphene oxide-multiwalled carbon nanotube) hybrid structure cathode electrocatalysts for high performance PEMFC applications

Abstract

The efforts to push proton exchange membrane fuel cells (PEMFC) for commercial applications are being undertaken globally. In PEMFC, the sluggish kinetics of oxygen reduction reactions (ORR) at the cathode can be improved by the alloying of platinum with 3d-transition metals (TM = Fe, Co, etc.) and with nitrogen doping, and in the present work we have combined both of these aspects. We describe a facile method for the synthesis of a nitrogen doped (reduced graphene oxide (rGO)–multiwalled carbon nanotubes (MWNTs)) hybrid structure (N–(G–MWNTs)) by the uniform coating of a nitrogen containing polymer over the surface of the hybrid structure (positively surface charged rGO–negatively surface charged MWNTs) followed by the pyrolysis of these (rGO–MWNTs) hybrid structure–polymer composites. The N–(G–MWNTs) hybrid structure is used as a catalyst support for the dispersion of platinum (Pt), platinum–iron (Pt₃Fe) and platinum–cobalt (Pt₃Co) alloy nanoparticles. The PEMFC performances of Pt–TM alloy nanoparticle dispersed N–(G–MWNTs) hybrid structure electrocatalysts are 5.0 times higher than that of commercial Pt–C electrocatalysts along with very good stability under acidic environment conditions. This work demonstrates a considerable improvement in performance compared to existing cathode electrocatalysts being used in PEMFC and can be extended to the synthesis of metal, metal oxides or metal alloy nanoparticle decorated nitrogen doped carbon nanostructures for various electrochemical energy applications.