MXene-based catalysts for water purification in the persulfate-based Fenton-like system

The rapid advancement of industrialization has led to widespread environmental contamination by persistent organic pollutants. These persistent organic pollutants, particularly Emerging Contaminants (ECs), exhibit extended environmental persistence and recalcitrance to degradation, presenting significant ecological and public health challenges. The Fenton-like reaction, a prominent advanced oxidation process (AOPs), has gained significant attention in water treatment research due to its rapid reaction kinetics and effective mineralization capability. MXenes have emerged as highly efficient heterogeneous catalysts for the Fenton-like reaction, owing to their large specific surface area, superior hydrophilicity, structural adaptability, and tunable surface chemistry. This review outlines the fundamental properties and synthesis methodologies of MXenes, with a dedicated focus on the latest research progress in loading transition metals and anchoring single atoms on MXenes. Synthesis methodologies and underlying mechanisms for loading transition metals and anchoring single atoms on MXene are systematically examined. This paper provides a detailed account of how MXene-based catalysts enhance their catalytic performance through strategies such as material structure, electron transfer pathways, and catalytic active sites, as well as the underlying reasons behind these enhancements. Additionally, the paper explores the impact of the persulfate-based AOPs on reaction kinetics under various conditions, while analyzing the corresponding reaction mechanisms. This paper also reviews the catalytic mechanisms for the generation of free radicals and non-free radical species in the persulfate-based Fenton-like system, with particular emphasis on the unique role of MXene-based catalysts in these processes. Finally, the challenges and opportunities faced by MXene-based catalysts in environmental remediation and industrial development were emphasized.