Solid state synthesis of a RuNiO3 perovskite nanomaterial as an electro-catalyst for direct alcohol (ethanol, methanol and ethylene glycol) fuel cell applications

Abstract

Direct alcohol fuel cells (DAFCs) are considered as reliable, clean and sustainable energy conversion technologies. However, most of them are reported using noble metal based electro-catalysts such as platinum (Pt), palladium (Pd) etc. which suffer from low cycling stability due to intermediate CO poisoning during the alcohol oxidation reaction (AOR). Herein, we report the solid-state synthesis of ruthenium nickel oxide (RuNiO₃) modified nickel foam (RNO/NF) as a cost-effective perovskite based electrocatalyst for DAFC applications. The RNO/NF catalyst electrode exhibits a high current density of ∼711.15 mA cm⁻² (0.4 M; ethanol), ∼475.05 mA cm⁻² (0.3 M; methanol) and ∼579.1 mA cm⁻² (0.3 M; ethylene glycol) at a potential of 0.8 V (vs. Hg|HgO). This superior performance of the RNO/NF electrode is ascribed to the presence of the Ni^2+/3+ redox couple at the tetrahedral sites favouring the AOR with the oxidation of CO into CO₂. The electrochemical active surface area of RNO/NF is estimated to be ∼175% greater than that of the bare NF which proves the activity of the electrode. The RNO/NF electrode displays high stability with a capacity retention of 88.79% (ethanol), 82.283% (methanol) and 95.54% (ethylene glycol) for 10 000 s which is higher than that of the commercial platinum-on-carbon (Pt/C) electro-catalyst, proving to be an ideal electrocatalyst for low-cost DAFC applications.