رومينا مهدوي

With the rapid growth of the global population, the limited availability of fossil fuel resources, an‎d the associated environmental pollution, researchers have sought suitable alternatives. Nowadays, hydrogen production through electrochemical water splitting has attracted significant attention due to its reliance on renewable resources an‎d environmental compatibility. Therefore, the design of highly efficient electrocatalysts for the hydrogen evolution reaction (HER) has gained particular importance. In the present thesis, the electrocatalyst Ni-P@Ni-Cu/NF was designed in three stages. In the first stage, a Ni-Cu layer was deposited on a nickel foam substrate via the electrochemical deposition method. In the second stage, selec‎tive electrochemical dealloying was applied to remove copper from the Ni-Cu alloy, leaving nickel nanotubes on the nickel foam substrate. Subsequently, in the third stage, a Ni-P layer was electrodeposited onto the nickel nanotubes using cyclic voltammetry. Optimization was performed by varying the number of cycles an‎d the scan rate. Electrochemical tests were carried out to eva‎luate the electrocatalytic activity of the optimized Ni-P@Ni-Cu/NF electrode for the HER in a 1M NaOH electrolyte. The results revealed that the optimized electrode, prepared at 30 cycles an‎d scan rate of 20 mV.s-1 , exhibited the highest catalytic activity, with overpotentials of –97 mV an‎d –239 mV at current densities of 10 an‎d 100 mA·cm⁻² (vs. RHE), respectively. Furthermore, it demonstrated excellent stability for at least 12 hours. Surface engineering an‎d the formation of nickel nanotubes significantly enhanced the catalytic performance compared to the Ni-P/NF electrode. Owing to its excellent performance, facile preparation, an‎d the absence of precious metals, the proposed electrode can be considered a highly promising can‎didate for hydrogen evolution via electrochemical water splitting. Keywords: Nickel nanotubes, Water splitting, Hydrogen evolution reaction, Electrodeposition, Electrochemical dealloying.

نانولوله‌هاي نيكل، شكافت الكتروشيميايي آب، واكنش تكامل هيدروژن، رسوب‌دهي الكتروشيميايي، آلياژزدايي الكتروشيميايي

Nickel nanotubes, Water splitting, Hydrogen evolution reaction, Electrodeposition, Electrochemical dealloying.

Romina Mahdavi

Dr. Ali Ghaffarinejad