Ligand and Strain Synergistic Effect in NiFeP_0.32 LDH for Triggering Efficient Oxygen Evolution Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient electrocatalysts are essential for accelerating the oxygen evolution reaction (OER) kinetics in water splitting for hydrogen production.
• Developing novel catalysts with enhanced activity and stability remains a significant challenge.

Purpose of the Study:

• To synthesize and characterize ultralow phosphorus-doped NiFe LDH (NiFePx LDH) as an efficient electrocatalyst for the oxygen evolution reaction (OER).
• To investigate the impact of phosphorus doping and compressive strain on the catalytic performance of NiFe LDH for OER.

Main Methods:

• Synthesis of ultralow phosphorus-doped NiFe LDH (NiFePx LDH) with controlled phosphorus content and compressive strain.
• Electrocatalytic performance testing for OER, including overpotential measurements.
• Density Functional Theory (DFT) calculations to elucidate the electronic structure and reaction mechanism.

Main Results:

• NiFePx LDH with 0.32 wt.% P and 2.53% compressive strain (NiFe0.32 LDH) exhibited an exceptionally low OER overpotential of 210 mV.
• The synthesized catalyst outperformed commercial IrO2 and other reported P-based OER electrocatalysts.
• DFT calculations confirmed that P doping forms Fe-P bonds, causing lattice distortion and electron depletion at Fe active sites, weakening *O intermediate adsorption.

Conclusions:

• Ultralow phosphorus doping in NiFe LDH, combined with mild compressive strain, significantly enhances OER activity.
• The improved performance is attributed to the unique electronic structure modifications induced by phosphorus, optimizing intermediate adsorption.
• This study offers valuable insights into designing high-performance electrocatalysts for water splitting through precise control of dopant coordination and lattice strain.