From surface terminations to functional nanoarchitectures: a chemistry-first framework for stabilizing and programming MXenes
MXenes combine metallic conductivity, solution processability, and chemically addressable surfaces, but the reactive interfaces that enable functionalization also accelerate oxidation, restacking, and property drift. This Mini Review develops a chemistry-first framework in which surface terminations, defects, adsorbates, and interlayer species are treated collectively as a coupled state variable rather than as independent descriptors. We link etching and delamination chemistry to termination populations and discuss the effects of water and oxygen on spatially heterogeneous degradation. We then examine how molecular ligands, polymers, inorganic phases, and mesoscale assembly modulate interfacial reactions and transport pathways. We organize recent studies according to a causal sequence: chemical intervention, nanoscale structural consequence, transport response, functional output, and failure mode. This sequence helps explain why nominally similar Ti3C2Tx materials can exhibit divergent electrochemical, catalytic, sensing, mechanical, and electromagnetic behavior. We argue that further progress depends less on identifying isolated applications than on controlling and reporting the evolving interfacial state across synthesis, storage, processing, and operation. We propose testable design rules for termination-aware synthesis, kinetic stabilization, interface-selective assembly, and operando validation. This framework positions MXenes as programmable reactive nanoarchitectures and identifies reproducibility, scalable fluorine-lean chemistry, and state-resolved characterization as priorities for nanoscience.