Hierarchical utilization of raw Ti₃C₂T_x MXene for fast preparation of various Ti₃C₂T_x MXene derivatives

Due to easy re-stacking, low yield of few-layered MXenes (f-MXenes), the applications of MXenes are mainly restricted in multi-layered MXenes (m-MXenes) state. Although f-MXenes can be prepared from m-MXenes, after exfoliation process, a mass of sediments which are still essentially compact MXenes are usually directly discarded, leading to low utilization of raw m-MXenes. Herein, a classified preparation strategy is adopted to exploit the raw m-MXenes and traditional MXenes sediments, taking multi-layered Ti₃C₂T_x MXene as an example. Via rational delamination and subsequent treatment to Ti₃C₂T_x sediments, we succeed in achieving classified and large-scale preparation of various Ti₃C₂T_x MXene derivatives, including few-layered Ti₃C₂T_x (f-Ti₃C₂T_x) powders, f-Ti₃C₂T_x films, and Ti₃C₂T_x MXene-derived nanowires with heterostructure of potassium titanate and Ti₃C₂T_x. We demonstrate the necessity of “step-by-step delamination” towards traditional Ti₃C₂T_x sediments to improve the yield of f-Ti₃C₂T_x from 15% to 72%; the feasibility of “solution-phase flocculation (SPF)” to fundamentally solve the re-stacking phenomenon, and oxidation degradation issues of f-Ti₃C₂T_x during storage; as well as the convenience of SPF to deal with time-consuming issues of fabricating Ti₃C₂T_x films. What’s more, alkali-heat treatment of final Ti₃C₂T_x sediments turns waste into treasure of Ti₃C₂T_x-derived nanowires, leading to 100% utilization of raw Ti₃C₂T_x. The content of one-dimensional (1D) nanowires in the hybrids can be adjusted by controlling alkalization time. The 3D architecture heterostructure composed of 1D nanowires and 2D nanosheets exhibits gorgeous application potential. This work can expand preparation and application of various MXenes derivatives, promoting process of various MXenes.