Structure-activity correlation of Ti₂CT₂MXenes for C-H activation

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• MXenes are emerging 2D materials with significant potential in heterogeneous catalysis.
• Their catalytic performance, particularly for reactions like C-H activation, is strongly influenced by surface termination groups and their arrangement.
• A deeper understanding of the structure-activity relationship is crucial for designing highly efficient MXene catalysts.

Purpose of the Study:

• To establish a quantitative descriptor linking the structure and catalytic activity of Ti2CT2 MXenes for C-H activation.
• To investigate the influence of different termination groups (O, OH, F) on this relationship.
• To develop a predictive model for MXene catalytic activity.

Main Methods:

• Computational analysis to determine the hydrogen affinity (EH) of Ti2CT2 MXenes with varying termination groups.
• Correlation analysis between mean hydrogen affinity and the ratio of oxygen terminations (xO).
• Validation of the structure-activity correlation across different C-H bond types (-CH3 and -CH2-).

Main Results:

• A linear correlation was identified between the mean hydrogen affinity and the proportion of oxygen terminations (xO) in Ti2CT2 MXenes.
• Catalytic activity increases as the oxygen content decreases, irrespective of the specific termination species.
• The hydrogen affinity is more sensitive to hydroxyl (OH) terminations than to fluorine (F) terminations.
• The established linear correlation accurately predicts the C-H activation activity for various Ti2CT2 MXene structures.

Conclusions:

• Hydrogen affinity serves as a reliable descriptor for predicting the C-H activation performance of Ti2CT2 MXenes.
• This quantitative relationship simplifies catalyst design by avoiding complex activation energy calculations.
• The findings are expected to accelerate the development and application of MXenes in heterogeneous catalysis.