Single-atom coordinated MXenes for organic pollutant detoxification: Mechanistic insights, challenges, and future directions

Abstract

Organic pollutants, including plastics, pharmaceuticals, aromatic compounds, pesticides, and industrial solvents, pose a serious threat to soil quality, aquatic ecosystems, and human health. Single-atom-coordinated MXenes (SAs@MXenes) have emerged as promising platforms for detoxifying organic pollutants because of their tunable surface chemistry, high catalytic activity, and atomic-level precision. Anchoring isolated metal atoms on the MXene surface maximizes atom utilization and modulates the electronic structure, thereby improving charge separation, adsorption affinity, and redox reactivity. However, comprehensive reviews of this emerging class of SAs@MXenes catalysts for organic pollutant detoxification remain limited. This review summarizes diverse synthesis strategies for achieving stable single-atom dispersion, including defect engineering to anchor single atoms at vacancy sites, heteroatom coordination chemistry, axial coordination, the modulation of local electronic structure through ligand control, and UV-mediated synthesis that enables photochemical precision in atom placement. In addition, advanced characterization techniques are used to confirm atomic dispersion, oxidation states, and structural evolution, while electron paramagnetic resonance (EPR) spectroscopy provides insight into the reactive intermediates responsible for detoxification. Furthermore, SAs@MXenes function as both efficient catalysts and a robust adsorbents for the degradation and capture of organic contaminants. Computational approaches, including density functional theory (DFT), machine learning (ML), and molecular dynamics (MD) simulations, are emphasized to elucidate catalytic mechanisms, accelerate catalytic design, and clarify molecular-level interactions. Collectively, these strategies support the rational development of single-atom–coordinated MXenes for sustainable environmental detoxification, and their future perspectives are also presented.