Abstract
NiCo-MOF-74 crystallized directly on the surface of porous NiO (p-NiO) film using a solvothermal method is proposed as an effective electrocatalyst for the anode in direct urea fuel cells. A nickel-to-cobalt ratio of 4:1 was found to show optimum catalytic activity toward urea oxidation with significant current enhancement in comparison to other electrodes, including Ni foil and p-NiO. At optimized conditions in an electrolyte solution of 3.0 M KOH and 1.0 M urea, a current density of around 110 mA cm-2 with a maximum power density of 4131 μW cm-2 can be produced. This is ascribed to the increase of the active surface area over conventional nickel-based anodes, providing an abundance of active sites for urea oxidation. Excellent stability and reproducibility over 15 h application in a direct urea fuel cell was obtained with cell voltage of ∼0.6 V. Powder X-ray diffraction shows the crystalline MOF film remains intact after chronoamperometry tests, and after fuel cell application, illustrating applicability in real devices.
Original language | English |
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Pages (from-to) | 2497-2507 |
Number of pages | 11 |
Journal | ACS Applied Energy Materials |
Volume | 6 |
Issue number | 4 |
DOIs | |
Publication status | Published - 27 Feb 2023 |
Keywords
- fuel cell
- MOF-74
- nickel-cobalt
- porous nickel oxide (NiO)
- urea oxidation