Overall Water-Splitting Enabled by Bifunctional NiPd/Pd Heterodimer Fabricated via In Situ Etching-Growth Route

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Developing cost-effective bifunctional electrocatalysts is crucial for efficient overall water-splitting.
• Existing catalysts often face challenges in terms of cost, efficiency, and stability.

Purpose of the Study:

• To design and synthesize a novel, low-cost bifunctional electrocatalyst for overall water-splitting.
• To evaluate the catalytic activity and stability of the synthesized material for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).

Main Methods:

• In situ etching-growth synthesis of NiPd/Pd heterodimers.
• Electrochemical characterization including overpotential measurements for HER and OER.
• Performance evaluation in a symmetric NiPd/Pd-2||NiPd/Pd-2 electrolyzer for overall water splitting.
• Post-reaction structural and chemical analysis.

Main Results:

• The optimized NiPd/Pd-2 heterodimer exhibited ultralow overpotentials: 15 mV for HER and 300 mV for OER at 10 mA cm^-2.
• The symmetric NiPd/Pd-2||NiPd/Pd-2 electrolyzer achieved overall water splitting at a low cell voltage of 1.36 V.
• The catalyst maintained its heterodimeric structure and showed enhanced stability in acidic conditions after prolonged operation.
• Stable operation for 24 hours without significant performance decay was demonstrated.

Conclusions:

• The NiPd/Pd heterodimer is a highly efficient and stable bifunctional electrocatalyst for overall water-splitting.
• This catalyst surpasses commercial benchmarks (Pt/C and RuO₂) in performance and efficiency.
• The developed catalyst holds significant potential for practical applications in sustainable energy-conversion devices powered by renewable sources.