Ni- and Co-Based\nMOF-Derived Ni<sub><i>x</i></sub>Co<sub>3–<i>x</i></sub>O<sub>4</sub> Materials:\nAs an Efficient Anode for Direct Methanol Fuel Cell Application

Finding inexpensive and efficient anode materials is\ncrucial for\nthe oxidation of methanol in the direct methanol fuel cell (DMFC),\nwhich is the key electrode reaction. Herein, we report metal–organic\nframework (MOF)-derived Co<sub>3</sub>O<sub>4</sub>, NiO, and Ni<sub><i>x</i></sub>Co<sub>3–<i>x</i></sub>O<sub>4</sub> (where <i>x</i> = 1.5, 1, and 0.6) materials deposited\non nickel foam as efficient anode material for methanol oxidation.\nAmong them, NiCo<sub>2</sub>O<sub>4</sub> exhibited the highest methanol\noxidation activity, owing to its lowest charge-transfer resistance\n(0.097 Ω) and high electrochemically active surface area (1950\ncm<sup>2</sup>), resulting in the lowest onset potential of 0.35 V\nvs Hg/HgO. The optimized Ni-to-Co ratio and synergistic effect between\nNi and Co metals enable NiCo<sub>2</sub>O<sub>4</sub> to achieve the\nhighest mass activity of 151 mA mg<sup>–1</sup> and geometric\ncurrent density of 288 mA cm<sup>–2</sup>, demonstrating excellent\ndurability over 14 h at 0.6 V. In addition, to optimize methanol concentration,\nall the electrocatalysts were tested in a range of methanol concentrations,\nshowing 0.5 M methanol as the optimal concentration. This study focuses\non optimizing the metal ratio and methanol concentration to achieve\nthe highest catalytic activity. Additionally, this lays the foundation\nfor developing diverse MOF-derived electrocatalysts and advancing\nDMFCs.