MXenes as multifunctional catalysts in Fenton-like reactions for water purification: Mechanisms, applications, and...

The persistent contamination of water resources by refractory organic pollutants necessitates the development of efficient advanced oxidation processes (AOPs). Fenton-like reactions, which generate highly reactive species for pollutant degradation, are particularly promising. MXenes, an emerging class of two-dimensional transition metal carbides/nitrides, have recently demonstrated exceptional potential as catalysts in these processes due to their large surface area, superior electrical conductivity, rich surface chemistry, and abundance of exposed active sites. This review provides a comprehensive and critical overview of the latest advancements in applying MXenes and MXene-based composites in Fenton-like reactions, centering on the activation of hydrogen peroxide (H₂O₂) and persulfate (PS). We begin by elucidating the fundamental properties and synthesis strategies of MXenes. The core of the review meticulously examines the mechanisms of H₂O₂ and PS activation by intrinsic MXenes, and various composites (e.g., with metals, metal oxides, and carbon materials), highlighting their efficacy in degrading a wide spectrum of organic contaminants. Furthermore, we analyze the multifaceted roles that MXenes play, such as serving as active centers, electron donors, and superior supports. The environmental impact and stability challenges of MXenes are also critically discussed. Finally, we present forward-looking perspectives on the key challenges and future research directions, such as deepening mechanistic understanding, enhancing stability, and assessing long-term environmental impact. This review aims to inspire further innovation in the rational design of high-performance MXene-based catalysts for sustainable water treatment.