Crusty-Structured Cu@NiCo Nanoparticles as Anode Catalysts in Alkaline Fuel Cells

Abstract

The use of non-platinum group metal (non-PGM) catalysts and liquid fuels is a good way to reduce the burden of commercialization and supply in fuel cells. However, it is very difficult to reach the power performance of commercial hydrogen-air fuel cells, 1.0-1.2 W cm(-2), with only non-PGM catalysts. In this study, we synthesize a crustlike Cu@NiCo/C nanocomposite as an anode catalyst for a direct liquid hydrazine fuel cell via facile polyol reduction by injecting a Ni-Co solution into a Cu solution. By systematically investigating their electrocatalytic performance toward hydrazine oxidation in an alkaline solution, an appropriate proportion of three different non-PGM metals is carefully selected. For further investigation, we conduct various electrochemical analyses on Cu@NiCo/C nanoparticles, namely, X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), and Tafel plot analyses, and confirm that the introduction of copper facilitates water adsorption and increases the conductivity of the catalyst. As a result, the application of Cu@NiCo/C as the anode catalyst of the hydrazine fuel cell can achieve a phenomenal power density of 1.08 W cm(-2). Importantly, the crusty structure maintains its shape after harsh single-cell testing. This strategy provides not only further insights into alkaline liquid fuel cells using non-PGM catalysts but also the possibility for replacing hydrogen fuel cells.