Ce/Gd Co-doping in NiFe LDH engineered oxygen vacancies for enhanced oxygen evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Nickel-iron layered double hydroxide (NiFe-LDH) is a promising electrocatalyst for the oxygen evolution reaction (OER).
• Enhancing the activity and stability of NiFe-LDH remains a key challenge for efficient water splitting.
• Oxygen vacancies are known to improve catalytic performance.

Purpose of the Study:

• To investigate the effect of co-doping with cerium (Ce) and gadolinium (Gd) on NiFe-LDH.
• To explore the role of oxygen vacancies and dopant segregation in OER performance.
• To evaluate the catalytic activity and long-term stability of the modified NiFe-LDH.

Main Methods:

• Co-doping of NiFe-LDH with Ce and Gd.
• Electrochemical characterization, including overpotential measurements at a current density of 10 mA cm⁻².
• Long-term stability testing of the catalyst.

Main Results:

• Co-doping successfully created abundant oxygen vacancies in the NiFe-LDH structure.
• Ce segregated into CeO₂ nano-islands, while Gd remained uniformly dispersed during OER.
• The Ce,Gd-NiFe LDH exhibited a 30 mV lower overpotential compared to pristine NiFe-LDH (228 mV) and maintained stable operation for over 140 hours.

Conclusions:

• The synergistic effect of Ce and Gd co-doping, coupled with the formation of oxygen vacancies and controlled dopant segregation, significantly enhances OER performance.
• Ce,Gd-NiFe LDH demonstrates superior activity and remarkable long-term stability, making it a highly promising electrocatalyst for OER.
• This study provides insights into rational catalyst design for improved electrochemical energy conversion.