Modulating Oxygen Evolution Reaction Pathways via (Oxy)Hydroxide-Driven Surface Reconstruction on Ti₃C₂ MXene...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• The oxygen evolution reaction (OER) is crucial for energy conversion technologies.
• Understanding OER pathways, such as adsorbate evolution (AEM) and lattice oxygen mechanism (LOM), is key to catalyst design.
• The oxygen path mechanism (OPM) offers a promising alternative with facile O-O coupling.

Purpose of the Study:

• To introduce an electro-activated reduced Ti3C2 MXene (rTi3C2) system for modulating OER pathways.
• To investigate the role of (oxy)hydroxide species in promoting OER activity.
• To demonstrate the transition from AEM to OPM on engineered MXene surfaces.

Main Methods:

• Operando Raman spectroscopy to observe in situ formation of surface species.
• Electrochemical measurements to assess OER performance (overpotential, current density).
• First-principles calculations to validate catalytic pathways and energy barriers.

Main Results:

• Electro-activation of rTi3C2 leads to the formation of (oxy)hydroxide species (rTi3C2-T).
• The rTi3C2-T system exhibited a 27% reduced OER overpotential and a 67% current density increase.
• Spectroscopic and computational data confirmed a shift towards the OPM pathway with reduced energy barriers.

Conclusions:

• Electrochemical surface engineering of MXenes can effectively promote the OPM pathway.
• The (oxy)hydroxide-rich rTi3C2-T catalyst demonstrates significantly enhanced OER activity.
• This work highlights a strategy for designing advanced OER catalysts through surface modification.