Phase-pure pentlandite Ni_4.3Co_4.7S₈ binary sulfide as an efficient bifunctional electrocatalyst for oxygen evolution...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical water splitting is crucial for clean energy production.
• Developing efficient, low-cost electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is essential.
• Non-noble metal catalysts are highly sought after to reduce the cost of water splitting.

Purpose of the Study:

• To synthesize a phase-pure pentlandite Ni4.3Co4.7S8 bifunctional electrocatalyst.
• To investigate its performance for both OER and HER in alkaline media.
• To understand the structure-property relationships governing its catalytic activity.

Main Methods:

• Hydrothermal synthesis using commercial nickel foam.
• Physicochemical characterizations (e.g., XRD, SEM, TEM).
• Electrochemical measurements (e.g., cyclic voltammetry, chronoamperometry).
• Density functional theory (DFT) computations.

Main Results:

• Phase-pure pentlandite Ni4.3Co4.7S8 was successfully synthesized.
• The catalyst exhibits a high-indexed (022) surface with a biomimetic hydrogenase-like structure.
• Ni4.3Co4.7S8 shows superior OER activity compared to RuO2 and comparable HER activity to Pt/C.
• DFT calculations reveal synergistic effects between Ni and Co, enhancing electronic properties and catalytic activity.

Conclusions:

• The synthesized Ni4.3Co4.7S8 is a highly efficient non-noble bifunctional electrocatalyst for water splitting.
• The study presents a novel strategy for synthesizing phase-pure pentlandite nickel cobalt binary sulfides.
• This material holds significant potential for low-cost electrochemical water splitting applications.