Ni/NiO coated on multi-walled carbon nanotubes as a promising electrode for methanol electro-oxidation reaction in direct methanol fuel cell

Abstract

In the current work, non-precious Nickel/Nickel oxide (Ni/NiO) and Ni/NiO/multi-walled carbon nanotube (Ni/NiO/MWCNT) composites were synthesized by combustion method for methanol oxidation. The fabricated catalysts were characterized by XRD, EDS, SEM, and TEM. From TEM micrographs, Ni/NiO with the particle size in the range of 20–30 nm was synthesized and uniformly embedded on MWCNTs with a diameter of 10–40 nm. It was found from the EIS results that the Ni/NiO/MWCNT has a lower charge transfer resistance than Ni/NiO, indicating a faster electron transfer from the Ni/NiO/MWCNT to methanol and faster reaction kinetics. The Ni/NiO/MWCNT catalyst showed a maximum peak current density of 15.94 mA cm−2 (49.81 mA mg−1) in peak potential of 0.43 mV (at room temperature) and long-term stability, showing good electrocatalytic activity. Also, DMFC single cell test based Ni/NiO/MWCNT anode catalyst showed a maximum power density of 41.8 mW cm−2, indicating its promising application in DMFC.