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.

Ultrawide Hydrazine Concentration Monitoring Sensor Comprising Ir−Ni Nanoparticles Decorated with Multi‐Walled Carbon Nanotubes in On‐Site Alkaline Fuel Cell Operation

“…Furthermore, the storage stability of the modified electrodes, which is critical for monitoring fuel concentration in alkaline media, was evaluated in a 1 M KOH solution containing 1 M hydrazine at a potential of −0.08 V for 500 s every day for seven days [see Figure 6b(i)] [46] . The sensor retained 85.18 % of its initial current response after seven days, indicating that it could be reused for up to six days.…”

“…The well‐dispersed mixture was sprayed with an airbrush onto the MGL 190 (AvCarb) anode support and 29 BC (Sigracet) cathode support until the Pt loading reached 1 mg cm −2 . The anion exchange membrane used was the same as that used in our previous studies [46,49] . The size of a membrane electrode assembly (MEA) of 25 cm 2 (5 x 5 cm) was fabricated by hot‐pressing for 5 min at 60 °C.…”

“…Furthermore, the storage stability of the modified electrodes, which is critical for monitoring fuel concentration in alkaline media, was evaluated in a 1 M KOH solution containing 1 M hydrazine at a potential of À 0.08 V for 500 s every day for seven days [see Figure 6b(i)]. [46] The sensor retained 85.18 % of its initial current response after seven days, indicating that it could be reused for up to six days. In addition, reproducibility was determined using the CA data for six electrodes with the same configuration in 1 M KOH solution containing 1 M hydrazine, and a relative standard deviation (RSD) of 2. indicating superb repeatability, was obtained after seven successive measurements using the same IrÀ NiÀ MWCNT/SPCE sensor in a 1 M hydrazine solution.…”

Performance Improvement of Gold Electrode towards Methanol Electrooxidation in Akaline Medium: Enhanced Current Density Achieved with Poly(aniline-co-2-hydroxyaniline) Coating at Low Overpotential

“…When considering an alkaline medium for methanol oxidation, one of the challenging tasks is the choice of the catalyst. It has been reported that electrooxidation of methanol in alkaline media attains structure sensitivity [10], which has made a way for utilizing precious metals [12], other than platinum and platinum-modified catalysts, like Ni, Pd, Ag, Cu@NiCo, and some kinds of perovskite oxide catalysts [13][14][15][16][17]. Some recent report shows efficient iron based catalyst [18] and palladium based catalyst mixed with rhodium, which showed higher faradic current densities for methanol electrooxidation than Pt and Pt-based catalysts in alkaline fuel cells [19].…”

Co Nanoparticle-Encapsulated Nitrogen-Doped Carbon Nanotubes as an Efficient and Robust Catalyst for Electro-Oxidation of Hydrazine

“…Therefore, it is vital to fabricate highly active, viable, and low-cost anode catalysts with a low overpotential for the demonstration of direct hydrazine fuel cells for different applications. In recent times, supported non-noble metal catalysts have been effectively prepared, and have progressively replaced the customary fuel cell catalysts that contain noble (precious) metals and their corresponding metal alloys in the electrooxidation reaction of hydrazine [29][30][31][32][33][34][35][36]. For instance, Duan and co-workers established a novel type of bendable electrode that was constructed using Cu nanocubes that were inserted into graphene paper via a simple electro-deposition process.…”