Ir-Induced Local Charge and Electron-Spin Regulation on CoNi LDH Electrocatalyst for Efficient Oxygen Evolution...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Nonprecious metal Cobalt-Nickel layered double hydroxides (CoNi LDHs) are promising oxygen evolution reaction (OER) catalysts due to low overpotential.
• Limitations include low electrical conductivity and strong adsorption of oxygen intermediates, hindering OER kinetics.
• Developing efficient and stable OER electrocatalysts is crucial for electrochemical water splitting.

Purpose of the Study:

• To enhance the OER performance of CoNi LDHs by doping with iridium.
• To investigate the catalytic activity, stability, and underlying mechanism of the ternary CoNiIr ZLDH electrocatalyst.
• To provide insights for designing advanced OER electrodes.

Main Methods:

• Synthesis of ternary CoNiIr ZLDH electrocatalyst derived from ZIF-67.
• Electrochemical characterization of OER performance, including overpotential and stability tests.
• Density functional theory (DFT) calculations to elucidate the catalytic mechanism.

Main Results:

• The CoNiIr ZLDH achieved low overpotentials of 202 mV and 280 mV at current densities of 10 and 100 mA cm⁻², respectively.
• The electrocatalyst demonstrated excellent stability, maintaining performance for nearly 24 hours under harsh OER conditions.
• DFT calculations revealed that iridium doping enhances conductivity and optimizes oxygen species adsorption via spin-orbit coupling.

Conclusions:

• Ternary CoNiIr ZLDH is a highly efficient and stable electrocatalyst for the oxygen evolution reaction.
• Iridium doping effectively overcomes the limitations of binary CoNi LDHs, significantly boosting OER performance.
• The study offers a novel strategy for designing high-performance OER electrocatalysts for water splitting.