Synthesis and antioxidant properties of Ti2N-MXenes with electron transfer and hydrogen donating mechanisms

Abstract

Reactive oxygen radicals are by-products of oxygen metabolism and are essential in physiological processes, but their excessive accumulation can lead to oxidative stress and damage. Two-dimensional transition metal carbides, carbon-nitrides and nitrides (MXenes), especially nitride-based MXenes with high electrical conductivity and biocompatibility, show potential for antioxidant applications. However, the synthesis of nitrogen-based MXenes has technical challenges, such as the high formation energy and low M–N bond cohesion energy. In this work, Ti₂N-MXenes, which have a two-dimensional structure with a complete Ti–N framework and rich N-containing functional groups, were successfully synthesized via a simple HF-KF immersing process. The synthesized nanosheets show outstanding scavenging efficiency against strong oxidants (KMnO₄), DPPH· radicals, and ROS (including superoxide and hydroxyl radicals). Furthermore, by analyzing the structural transformation and electron transfer during the interaction of MXenes with DPPH·, it was found that the efficient radical scavenging ability stems from the inherent electron-richness, hydrogen-donating and electron-transferring capabilities. This innovative synthesis method and the remarkable antioxidant activity of Ti₂N-MXenes offer a promising prospect for the application of nitride-based MXenes in various fields, such as biomedicine, environmental protection and material science.

Graphical Abstract