Work function regulation of surface-engineered Ti₂CT₂ MXenes for efficient electrochemical nitrogen reduction...

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Electrochemical nitrogen fixation to ammonia offers a sustainable alternative under mild conditions.
• Developing efficient electrocatalysts and understanding their mechanisms are crucial for practical applications.

Purpose of the Study:

• Investigate the catalytic mechanism of defective Ti2CT2 MXenes for nitrogen reduction reaction (NRR).
• Explore the synergetic effect of terminal vacancies and transition metal active centers.
• Understand how surface functional groups influence electron transfer and catalytic activity.

Main Methods:

• Employed first-principles calculations to study defective Ti2CT2 MXenes with various functional groups (O, F, H, OH).
• Analyzed the electronic properties and work function regulation.
• Investigated the nitrogen adsorption and activation mechanism.

Main Results:

• Electron transfer in 2D transition metal carbides is tunable via surface functional groups.
• Work function regulation effectively optimizes intermediate binding strength.
• Ti2CO2 with an oxygen vacancy shows promise, activating N2 via a distal mechanism through in-gap states.
• Observed orbital splitting and hybridization, illustrating nitrogen activation through an "acceptance-donation" interaction.

Conclusions:

• The synergetic effect of vacancies and transition metal atoms is key to efficient NRR.
• Work function tuning offers a novel strategy for designing NRR electrocatalysts.
• Defective Ti2CO2 MXenes present a promising avenue for sustainable ammonia synthesis.