Highly Efficient Hybrid Ni/Nitrogenated Graphene Electrocatalysts for Hydrogen Evolution Reaction

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing efficient electrocatalysts for hydrogen evolution reaction (HER) is crucial for renewable energy technologies.
• Nickel-based materials are promising for HER but often require modification to enhance activity and stability.
• Nitrogen-doped carbon materials offer unique electronic properties beneficial for catalysis.

Purpose of the Study:

• To synthesize and characterize two novel nickel/nitrogenated graphene hybrid electrodes (Ni-NrGO).
• To evaluate the catalytic activity and stability of these electrodes for HER in alkaline media.
• To compare the performance of Ni-NrGO electrodes with conventional nickel electrodes.

Main Methods:

• Synthesis of nitrogenated reduced graphene oxide (NrGO) via hydrothermal method and nitrogenated graphene oxide (NGO) via APTES functionalization.
• Preparation of Ni-NrGO hybrid electrodes by incorporating NrGO and NGO into a nickel Watts plating bath.
• Electrochemical characterization using cyclic voltammetry and electrochemical impedance spectroscopy in KOH solution.

Main Results:

• The Ni-NrGO catalysts exhibited significantly higher HER activity compared to conventional nickel electrodes.
• Electrodes containing APTES-functionalized NGO (Ni-NrGO) achieved a 130% higher hydrogen current density.
• Both hybrid catalysts demonstrated low deactivation rates, indicating enhanced stability and longer operational midlife.
• High exchange current densities were recorded: 8.53 × 10⁻⁴ mA cm⁻² for Ni-NrGO and 2.53 × 10⁻⁵ mA cm⁻² for Ni-NrGO.

Conclusions:

• Nitrogenated graphene structures, particularly when functionalized with APTES, effectively enhance the HER performance of nickel electrodes.
• The developed Ni-NrGO hybrid electrodes represent a promising advancement for efficient hydrogen production in alkaline electrolytes.
• The improved activity and stability suggest these materials are suitable for practical electrochemical applications.