Lignin-assisted electronic modulation on NiSe/FeO_x heterointerface for boosting electrocatalytic oxygen evolution...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• The oxygen evolution reaction (OER) is crucial for water splitting but is kinetically hindered.
• Developing efficient and stable non-precious metal catalysts is essential for cost-effective hydrogen production.
• Existing catalysts often suffer from poor durability and low activity.

Purpose of the Study:

• To synthesize and characterize a novel NiSe-FeOₓ heterojunction encapsulated in lignin-derived carbon (NiSe-FeOₓ@LC).
• To evaluate the electrocatalytic performance of NiSe-FeOₓ@LC for the oxygen evolution reaction (OER).
• To elucidate the mechanism behind the enhanced OER activity and stability.

Main Methods:

• Hydrothermal self-assembly and in-situ pyrolysis for catalyst synthesis.
• Electrochemical testing (overpotential, Tafel slope, long-term stability) to assess OER performance.
• Density Functional Theory (DFT) calculations to understand electronic structure and reaction mechanisms.

Main Results:

• NiSe-FeOₓ@LC demonstrated superior OER activity with a low overpotential (265 mV at 50 mA·cm⁻²) and an excellent Tafel slope (83 mV·dec⁻¹).
• The catalyst exhibited remarkable long-term stability, indicating resistance to leaching and agglomeration.
• DFT calculations confirmed that FeOₓ doping optimized the NiSe-FeOₓ interface, enhancing d-band orbital hybridization and facilitating electron transfer.

Conclusions:

• The lignin-derived carbon encapsulation effectively protects the active NiSe-FeOₓ components, ensuring catalyst durability.
• The synergistic interaction between NiSe and FeOₓ within the carbon matrix significantly boosts OER performance.
• This work highlights the potential of lignin-derived carbon-encapsulated metallic catalysts for efficient electrocatalytic water splitting.