Highly Active NiO-Ni(OH)₂ -Cr₂ O₃ /Ni Hydrogen Evolution Electrocatalyst through Synergistic Reaction Kinetics

Area of Science:

• Electrochemistry
• Materials Science
• Renewable Energy

Background:

• High activity catalysts are crucial for efficient hydrogen evolution reaction (HER) in converting renewable electricity to hydrogen fuel.
• Developing noble metal-free catalysts is essential for the economic viability of water electrolysis.
• Current research focuses on identifying alternative materials with catalytic activity comparable to platinum.

Purpose of the Study:

• To report a novel non-precious metal oxide/metal catalyst for HER.
• To evaluate the catalytic activity and performance of the developed electrocatalyst.
• To elucidate the synergistic mechanisms underlying the catalyst's enhanced performance.

Main Methods:

• Synthesis and characterization of a multi-component catalyst comprising NiO, Ni(OH)2, Cr2O3, and Ni metal.
• Electrochemical testing in 1.0 m NaOH electrolyte to measure overpotentials at various current densities.
• Density functional theory (DFT) calculations to investigate reaction mechanisms and surface interactions.

Main Results:

• The NiO, Ni(OH)2, Cr2O3, and Ni metal catalyst exhibited low overpotentials (27, 103, 153 mV at 10, 100, 200 mA cm-2).
• The catalyst's activity significantly surpassed that of individual components (NiOx/Ni or Cr2O3), indicating synergistic effects.
• DFT calculations revealed lowered dissociation energy barriers and optimized H* adsorption free energy on the Ni surface.

Conclusions:

• The synergistic interaction between multiple oxides and metal components enhances both H-OH bond dissociation and H* to H2 evolution.
• This novel catalyst composition demonstrates high activity for HER, comparable to platinum-based catalysts.
• The findings present a promising strategy for designing efficient, noble metal-free electrocatalysts for hydrogen production.