Fe-Co LDH/MoP heterostructure with Fe and Co as intercalants for oxygen evolution electrocatalysis.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Oxygen evolution reaction (OER) is a bottleneck in water splitting due to sluggish kinetics.
• Layered double hydroxides (LDHs), like Fe-doped Co-based hydroxides (Fe-Co(OH)2), show promise as affordable OER catalysts.
• Enhancing active site exposure and electrical conductivity is key to improving LDH catalyst performance.

Purpose of the Study:

• To develop a novel Fe-Co(OH)2/MoP heterostructure for enhanced OER electrocatalysis.
• To improve active site exposure and electrical conductivity of Fe-Co(OH)2 catalysts.
• To investigate the mechanism behind the enhanced OER activity.

Main Methods:

• A "MoO3 intercalation-phosphorization" protocol was used to synthesize the Fe-Co(OH)2/MoP heterostructure.
• Atomic dispersion of Fe and Co in the MoO3 van der Waals gap as precursors.
• Electrocatalytic activity for OER was evaluated using techniques like overpotential and Tafel slope measurements.
• Experimental and theoretical studies were conducted to understand the catalytic mechanism.

Main Results:

• The Fe-Co(OH)2/MoP heterostructure exhibited remarkable electrocatalytic activity for OER.
• Achieved overpotential of 240 mV at 10 mA cm-2 and a Tafel slope of 39.6 mV dec-1.
• Fe doping induced superexchange interaction, facilitating Co(III) active species formation.

Conclusions:

• The novel Fe-Co(OH)2/MoP heterostructure significantly enhances OER performance.
• The "MoO3 intercalation-phosphorization" method effectively improves catalyst design.
• Understanding the electronic interactions provides insights for designing advanced electrocatalysts.