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چکیده
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A three-step approach was adopted to fabricate 3D porous Ni-Fe-Mn-Se cubes. First, the Mn-PB precursor was prepared using a simple deposition method. In a subsequent phase, the Ni/Mn-PB nanostructure was synthesized using a fast and easy ion exchange-based process. Finally, the Ni-Fe-Mn-Se cubes were obtained by performing a selenization heat treatment in a nitrogen atmosphere. These cubes were able to show a 249 mV overpotential for the oxygen evolution reaction (OER) at a 10 mA cm2 current density. The outstanding electrocatalytic activity of this nanocomposite is attributed to several features: 1. Synergy of elements and improvement of electronic properties: Through doping with heteroatom element and process of phosphidation, the electronic structure is changed and between the elements occur the synergistic effects, creating abundant structural defects and numerous catalytic centers. This leads to increased conductivity and improved electrochemical behavior, ultimately contributing to attractive electrocatalytic performance. 2. 3D porous and hollow architecture: This design provides a three-dimensional path for the diffusion of electrolyte ions. This feature greatly enhances mass and charge transfer and significantly improves electrocatalytic performance by providing more catalytic sites. 3. Facilitating gas bubble diffusion: The cubic and porous structures are designed to facilitate the diffusion of gas bubbles produced in the reaction. 4. Improving the properties of active materials through phosphiding: The phosphiding process leads to the strengthening of electrocatalytic active materials and increases their conductivity, porosity, and stability.
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