Interface‐Engineered MXene/g‐C 3 N 4 Heterostructures for Energy and Environmental Applications

ABSTRACT Two‐dimensional MXene/g‐C 3 N 4 heterostructures have recently emerged as a versatile platform for energy conversion and environmental remediation. Benefiting from the tunable conductivity of MXene and tailorable structure of g‐C 3 N 4 , these hybrids offer rich opportunities for engineering interfacial band alignment, built‐in electric fields, and reaction microenvironments. This review outlines the significant contribution of work–function matching, surface termination, and defect chemistry in mediating interfacial charge generation, separation, and transfer in MXene/g‐C 3 N 4 composites. We summarize recent progress in the applications of MXene/g‐C 3 N 4 heterostructures for photocatalytic reactions, including H 2 evolution, CO 2 reduction, H 2 O 2 production, N 2 fixation, and pollutant degradation, highlighting the critical role of MXene in dictating carrier dynamics and reaction pathways. The contribution of MXene/g‐C 3 N 4 heterostructures to persulfate/peroxymonosulfate (PDS/PMS) activation, supercapacitors, lithium‐based batteries, and emerging multifunctional applications, including biosensing, gas sensing, and photothermal therapy, is further discussed, emphasizing the potential of 2D MXene/g‐C 3 N 4 for multifunctional applications. Finally, we elucidate the significance of surface chemistry control, defect engineering, and interfacial design for addressing the key challenges in the development of next‐generation MXene/g‐C 3 N 4 systems, which are essential for translating laboratory demonstrations into robust devices under realistic operating conditions.