MXene Quantum Dots for Multifunctional Water Remediation: Bridging Photocatalysis, Electrocatalysis, and Fluorescent Sensing

ABSTRACT Water pollution and the need for sustainable water treatment have become critical global challenges, demanding innovative material solutions. In this review, we systematically analyzed the functional roles of MXene quantum dots (MQDs) in aquatic systems, focusing on their applications in photocatalytic pollutant degradation, water splitting, and fluorescence‐based sensing of metal ions and organic contaminants. MQDs, with zero‐dimensional quantum confinement and abundant edge sites, facilitate efficient interfacial charge separation, rapid electron–hole dynamics, and size‐dependent photoluminescence. Integration of MQDs into Z‐scheme photocatalytic architectures, plasmonic hybrids, and edge‐enriched electrocatalysts enhances carrier utilization, broadens light absorption, and accelerates reaction kinetics. For sensing applications, the intrinsic redox activity of MQDs enables selective electron transfer with target analytes, producing “turn‐on” and “turn‐off” fluorescence responses suitable for complex aqueous environments. Hybridization with complementary quantum materials and conductive scaffolds further improves structural stability, prevents aggregation, and promotes efficient charge transport. Overall, this review highlights the versatility and tunability of MQDs, demonstrating their potential as multifunctional platforms for integrated energy conversion and sustainable water quality monitoring, and represents the first comprehensive review focused on this topic.