Molybdenum-induced interfacial electron pump stabilizes γ-NiOOH for efficient electrooxidation conversion of methanol...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The intrinsic instability of the active γ-NiOOH phase limits nickel-based electrocatalyst performance in the methanol oxidation reaction (MOR).
• Developing stable and efficient electrocatalysts is crucial for advancing energy conversion technologies.

Purpose of the Study:

• To stabilize the γ-NiOOH lattice and enhance MOR efficiency using a molybdenum (Mo)-induced interfacial electron pump strategy.
• To investigate the electronic modulation effects of Mo on Ni sites for improved catalytic activity.

Main Methods:

• A two-step strategy involving electrolysis and solvothermal reaction was employed to synthesize NiMo/graphene (NiMo/G) composites.
• The NiMo/G composites feature Ni-O-Mo interfaces designed to act as electron sinks, stabilizing the active γ-NiOOH phase.

Main Results:

• The Mo-induced electron pump strategy effectively stabilized the γ-NiOOH lattice, lowering the formation barrier by ~150 mV.
• Optimized adsorption energetics for intermediates reduced the energy barrier of the rate-determining step from 0.68 to 0.46 eV.
• The NiMo/G catalyst exhibited high area activity (320.6 ± 5.2 mA cm⁻²) and mass activity (15,638.9 ± 254.1 mA mgNi⁻¹).

Conclusions:

• Interfacial electron pump engineering is a powerful strategy for stabilizing high-valent active phases in electrocatalysis.
• This approach offers a general method for designing advanced electrocatalysts for energy conversion and storage.
• The developed NiMo/G catalyst demonstrates significant potential for efficient methanol oxidation reactions.