Engineering Mo₂TiC₂T_x MXene Electrocatalyst via Metal-Ion Intercalation Toward Efficient Hydrogen Evolution Reaction

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Scalable green hydrogen production relies on efficient, stable, and low-cost nonprecious metal electrocatalysts for the hydrogen evolution reaction (HER).
• MXene materials offer potential as catalyst supports due to their unique properties, but require tailored modifications to enhance HER performance.

Purpose of the Study:

• To design and fabricate high-performance MXene-based HER catalysts using a metal ion intercalation strategy.
• To investigate the effect of different metal ion intercalants (Co2+, Mn2+, Ni2+) on the structure and HER activity of Mo2TiC2Tx.
• To elucidate the mechanism behind the enhanced catalytic activity observed in Ni2+-intercalated Mo2TiC2Tx.

Main Methods:

• Fabrication of MXene-based catalysts via metal ion intercalation (Co2+, Mn2+, Ni2+) into Mo2TiC2Tx.
• Systematic electrochemical characterization of the synthesized catalysts for HER performance in 0.5 M H2SO4.
• In-depth investigation of the electronic structure and bonding in Ni2+-Mo2TiC2Tx using advanced analytical techniques.

Main Results:

• Intercalation of Co2+, Mn2+, and Ni2+ ions induced interlayer expansion in Mo2TiC2Tx, exposing active sites.
• Ni2+ intercalation formed Ni-O-Mo bonds, creating strong electronic interactions and enhancing charge transfer.
• The optimal 1 mM Ni2+-Mo2TiC2Tx catalyst exhibited an overpotential of 93 mV at 10 mA cm-2 for HER and maintained stability for over 700 hours.

Conclusions:

• Metal ion intercalation is an effective strategy for designing high-performance MXene-based HER catalysts.
• The synergistic control of interlayer spacing and electronic structure, particularly through Ni2+ incorporation, significantly boosts catalytic activity and durability.
• This work presents a promising pathway for developing advanced electrocatalysts for sustainable hydrogen production.