MXene-based photocatalysts for organic pollutant degradation: synthesis, functional properties, mechanisms, and kinetic insights.

The rapid proliferation of organic pollutants in aquatic environments has intensified the search for efficient and scalable remediation technologies. MXene-based materials, a growing class of two-dimensional transition metal carbides, nitrides, and carbonitrides, have emerged as highly promising photocatalysts owing to their exceptional electrical conductivity, tunable surface chemistry, high surface area, and broad light absorption. This review comprehensively examines the engineering of MXene-based composites for the photocatalytic degradation of organic pollutants, covering key synthesis strategies, including hydrothermal, solvothermal, in situ, self-assembly, and calcination routes. The structural diversity of MXene families and the physicochemical properties governing their photocatalytic performance, including synergistic composite interactions, photocatalytic properties, optical behavior, and biosafety, are critically discussed. Factors influencing degradation efficiency, including photocatalyst dosage, pollutant concentration, pH, and temperature, are systematically analyzed. The mechanistic pathways of pollutant mineralization and the kinetic behavior of MXene-based systems, both in the presence and absence of oxidants, are evaluated with reference to current literature. Unlike prior reviews that discuss MXenes in broader contexts, this work uniquely integrates mechanistic and kinetic analyses within a unified framework, providing targeted insights for the rational design of photocatalysts. This review concludes with future perspectives aimed at overcoming existing limitations and accelerating the practical deployment of MXene-based photocatalysts for water treatment applications.