Tailoring Nickel Porous Structure via Dynamic Hydrogen Bubble Template for Efficient Alkaline Hydrogen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Nanoporous nickel (Ni_np) films are promising electrocatalysts for the hydrogen evolution reaction (HER).
• Optimizing synthesis parameters is crucial for enhancing catalytic activity and stability.

Purpose of the Study:

• To synthesize Ni_np films using the dynamic hydrogen bubble template (DHBT) method.
• To investigate the effect of deposition parameters on Ni_np structure, morphology, and HER performance.
• To explore the role of Ti and Ni substrates in Ni_np synthesis and catalysis.

Main Methods:

• Synthesis of Ni_np films via DHBT on Ti and Ni substrates.
• Systematic variation of deposition current density (0.5-2.0 A cm^-2) and duration (50-300 s).
• Characterization using SEM, electrochemical techniques (HER polarization, chronoamperometry, EIS), and DFT calculations.

Main Results:

• Higher current densities and longer deposition times resulted in homogeneous Ni_np with cauliflower-like morphology.
• Optimal electrodes (2.0 A cm^-2, 300 s) showed low overpotentials (158 mV on Ti, 180 mV on Ni) and 24-hour stability.
• DFT calculations revealed enhanced hydrogen adsorption on Ti substrates due to interstitial oxygen.

Conclusions:

• DHBT is an efficient method for producing high-performance Ni_np electrocatalysts.
• Deposition parameters and substrate choice significantly impact HER catalytic activity and stability.
• Developed Ni_np catalysts show potential for sustainable hydrogen production.