Redox-Durable Co-Ni-Fe Layered Double Hydroxide Anode for Stable Oxygen Evolution under Industrially Relevant Cycling

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing robust electrocatalysts for the oxygen evolution reaction (OER) is critical for efficient hydrogen production via electrolysis powered by renewable energy.
• Industrially relevant conditions, particularly intermittent operation (start-up/shutdown cycles), pose significant challenges to catalyst durability.

Purpose of the Study:

• To investigate the degradation mechanisms of NiFe-, CoFe-, and CoNiFe-layered double hydroxide (LDH) electrocatalysts under repeated on-off cycling conditions.
• To identify the structural and chemical factors contributing to catalyst stability and degradation during intermittent operation.

Main Methods:

• Operando Raman spectroscopy
• Operando X-ray absorption spectroscopy (XAS)
• Electrochemical analysis

Main Results:

• NiFe-LDH showed severe degradation due to decreased conductivity, suppressed Ni oxidation, and amorphization under intermittent operation.
• CoFe-LDH exhibited the poorest performance and significant Fe dissolution during cycling.
• CoNiFe-LDH demonstrated exceptional durability, attributed to its stable framework and synergistic electronic interactions between Co and Ni, which facilitated Ni oxidation and maintained redox ability.

Conclusions:

• CoNiFe-LDH exhibits superior durability for oxygen evolution reaction (OER) under industrially relevant intermittent operating conditions (600 mA cm⁻², 60 °C).
• The structural integrity and redox robustness of CoNiFe-LDH make it a highly promising electrocatalyst for durable alkaline electrolyzers in mass hydrogen production.