CoP-nanorod-doped Co heterostructured electrode for efficient electrocatalytic hydrogen evolution reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient electrocatalysts is crucial for hydrogen evolution reaction (HER) in sustainable energy technologies.
• Heterogeneous structures and synergistic effects are key to enhancing electrocatalytic activity and stability.

Purpose of the Study:

• To design and synthesize a high-performance cobalt phosphide-doped cobalt metal on nickel foam (CoP/Co/NF) electrocatalytic electrode.
• To investigate the synergistic effects of heterogeneous Co and CoP structures for improved electrocatalysis.
• To evaluate the catalytic activity, stability, and mechanism of the CoP/Co/NF electrode for HER.

Main Methods:

• A two-step synthesis strategy involving electrodeposition and low-temperature phosphorization.
• Characterization of the electrode's hierarchical architecture and electrochemical active surface area (ECSA).
• Electrochemical testing in 1 M KOH electrolyte to assess HER performance, including overpotential and Tafel slope.
• Long-term stability testing and theoretical DFT calculations.

Main Results:

• The CoP/Co/NF electrode exhibited a hierarchical sea-urchin-like architecture with a large ECSA (537.5 cm²).
• Excellent catalytic activity for HER was observed, with optimized overpotentials of 23 mV at 10 mA cm⁻² and 56 mV at 100 mA cm⁻².
• The catalyst demonstrated a low Tafel slope (27.1 mV dec⁻¹) and remarkable stability over 100 hours at 100 mA cm⁻².
• DFT calculations indicated that the CoP/Co interface is electron-rich, facilitating water dissociation and optimizing hydrogen adsorption.

Conclusions:

• The designed CoP/Co/NF electrode shows exceptional performance for the hydrogen evolution reaction.
• The hierarchical heterogeneous structure and synergistic effects between CoP and Co are responsible for the enhanced electrocatalytic activity and stability.
• This material holds significant promise for efficient and durable hydrogen production.