سينا زماني

Electrochemical reactions, especially in renewable energy systems like fuel cells an‎d metal-air batteries, play a crucial role. One of the key reactions in these systems is the Oxygen Reduction Reaction (ORR), whose performance is significantly influenced by the type of electrocatalyst used. Due to the high cost of precious metals like platinum, commonly used as electrocatalysts, extensive research has focused on finding more cost-effective an‎d efficient alternatives. The main objective of this research was to enhance efficiency an‎d reduce the overpotential of electrochemical reactions through the development of new electrocatalysts.In this study, the performance of Ni-Fe, Ni-Cu, Ni-Co, Ni-Ni, Ni-Mn bimetallic electrocatalysts an‎d single atom Ni was eva‎luated as substitutes for precious metals using Density Functional Theory (DFT) calculations. The results indicated that the optimal binding energy of each metal atom with four nitrogen atoms performed better as an electrocatalyst compared to binding with three nitrogen atoms. Additionally, according to Density of States (DOS) an‎d Projected Density of States (PDOS) curves, bimetallic electrocatalysts exhibited more free electrons than single atom electrocatalysts.The results related to adsorption energy showed that Co-Ni had high binding energies for *O (4.93 eV) an‎d *OH (-3.07 eV), while Cu-Ni had binding energies closer to those of platinum, with lower energy required for OH- desorption. When comparing various catalysts, Cu-Ni exhibited a lower overpotential of 0.5 volts an‎d a limiting potential of 0.1 V, suggesting that Cu-Ni could be more favorable for ORR compared to other compounds. Based on the free energy change data, it can be concluded that Ni-Cu, Ni-Ni, Ni-Co, Ni-Fe, an‎d Ni-Mn electrocatalysts show the best performance in alkaline environments.Overall, this research demonstrated that bimetallic electrocatalysts can serve as efficient an‎d cost-effective alternatives to precious metals an‎d can play a significant role in developing renewable energy systems. Furthermore, the use of DFT calculations has proven to be an effective tool in optimizing electrocatalyst structures an‎d enhancing their performance.

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Sina Zamani

dr Sosan Roshan Zamir