Pseudocapacitive Ni-Co-Fe Hydroxides/N-Doped Carbon Nanoplates-Based Electrocatalyst for Efficient Oxygen Evolution.

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Oxygen evolution reaction (OER) electrocatalyst activity is linked to pseudocapacitance at potentials below the standard OER potential.
• Enhanced pseudocapacitance can significantly boost OER performance.

Purpose of the Study:

• To synthesize a highly pseudocapacitive electrocatalyst for improved OER.
• To investigate the relationship between pseudocapacitance and OER activity in transition metal hydroxides.

Main Methods:

• Facile one-pot solvothermal synthesis of Ni-Fe-Co hydroxides/N-doped carbon nanoplates (NiCoFe-NC).
• Electrochemical characterization including cyclic voltammetry and chronoamperometry.
• Material analysis using X-ray photoelectron spectroscopy and surface area measurements.

Main Results:

• NiCoFe-NC exhibited high specific capacitance (1849 F g^-1) and energy density (31.5 Wh kg^-1).
• The catalyst demonstrated excellent OER activity, comparable to RuO₂, with low overpotential (160 mV) and Tafel slope (31 mV dec^-1).
• The OER performance remained stable for 24 hours.

Conclusions:

• The superior OER activity is attributed to the 2D layered structure of Ni-Co hydroxides, synergistic Fe(III) interactions, and enhanced hydrophilicity from N-doped carbon.
• This work presents a general strategy for designing high-performance metal (hydr)oxide-based OER electrocatalysts.