Solar exfoliated graphene–carbon nanotube hybrid nano composites as efficient catalyst supports for proton exchange membrane fuel cells

Abstract

Ultra thin graphene–multi walled carbon nanotube composites prepared by a solar exfoliation technique have been explored as catalyst supports for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFC). Pt nanoparticles were dispersed on a solar exfoliated graphene-functionalized multi walled carbon nanotube (sG-fMWNT) hybrid nanocomposite, which exhibits higher electrocatalytic activity for ORR than Pt dispersed functionalized solar graphene (f-sG) catalyst support. The single cell PEMFC measurements give maximum power densities of 355 mW cm⁻² and 675 mW cm⁻² with sG and sG-f MWNT respectively. The improved performance in the power density with the sG-f MWNT fuel cell can be ascribed to the synergistic effect of 1D MWNT and 2D graphene in sG-f MWNT as well as its high electrochemical surface area. The inclusion of MWNT bridges the defects for electron transfer besides increasing the basal spacing between graphene sheets. The good performance and possibility of high throughput production of sG-f MWNT makes this material a promising catalyst support for PEMFC.