Optimized Ni(II)-doping in Co(III)-based layered double hydroxides towards electrochemical oxygen evolution catalysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical water-splitting requires efficient oxygen evolution reaction (OER) catalysts for practical applications.
• Layered double hydroxides (LDHs) are promising candidates for OER catalysis due to their tunable structures.

Purpose of the Study:

• To screen and optimize nickel(II)-doping in cobalt(III)-based LDHs for enhanced OER activity and stability.
• To investigate the synergistic effects of Ni-Co interactions on OER performance.

Main Methods:

• Synthesis of Ni(II)-doped Co(III)-based LDHs via oxidative intercalation.
• Electrochemical characterization including OER activity and stability measurements.
• In situ Raman spectroscopy and Fourier-transformed alternating current voltammetry to study reaction mechanisms.

Main Results:

• A volcano-like trend in OER activity was observed with varying Ni(II) doping levels.
• Optimized doping (x=0.20) yielded a catalyst exceeding Ni(II)-Fe(III) LDHs in activity at overpotentials > 375 mV.
• Ni cations were found to promote Co(IV)-oxo intermediate formation, accelerating OER kinetics.

Conclusions:

• Ni-doping in Co-based LDHs is an effective strategy to enhance OER performance.
• Synergistic communication between Ni and Co cations is crucial for the observed volcano-like activity trend.
• The developed catalyst shows significant potential for electrochemical water-splitting.