Ru–Ni nanoparticles electrodeposited on rGO/Ni foam as a binder-free, stable and high-performance anode catalyst for direct hydrazine fuel cell

Abstract

Bimetallic Ru–Ni nanoparticles was synthesized on the reduced graphene oxide decorated Ni
foam (Ru–Ni/rGO/NF) by electroplating method to be utilized as the anode electrocatalyst for
direct hydrazine-hydrogen peroxide fuel cells (DHzHPFCs). The synthesized electrocatalysts were
characterized by X-ray diffraction, Field emission scanning electron microscopy, Fourier trans-
form infrared spectroscopy, and Raman spectroscopy. The electrochemical properties of catalysts
towards hydrazine oxidation reaction in an alkaline medium were evaluated by cyclic voltam-
metry, chronoamperometry, and electrochemical impedance spectroscopy. In the case of
Ru1–Ni3/rGO/NF electrocatalyst, Ru1–Ni3 provided active sites due to low activation energy
(22.24 kJ mol 1) for hydrazine oxidation reaction and reduced graphene oxide facilitated charge
transfer by increasing electroactive surface area (EASA = 677.5 cm2) with the small charge
transfer resistance (0.1 Ω cm2). The CV curves showed that hydrazine oxidation on the synthe-
sized electrocatalysts was a first-order reaction in low concentrations of N2H4 and the number of
exchanged electrons was 3.0. In the single cell of the of direct hydrazine-hydrogen peroxide fuel
cell, the maximum power density value of Ru1–Ni3/rGO/NF electrocatalyst was 206 mW cm 2
and the open circuit voltage was 1.73 V at 55 ◦C. These results proved that the Ru1–Ni3/rGO/NF
is a promising candidate for using as the free-binder anode electrocatalyst in the future appli-
cation of direct hydrazine-hydrogen peroxide fuel cells due to its excellent structural stability,
ease of synthesis, low cost, and high catalytic performance.