Universal Synthesis of Core–Shell-Structured Ordered Mesoporous Transition Metal Dichalcogenides/Metal Oxides Heterostructures with Active Edge Sites

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDs) are widely used in interfacial reactions and electronic devices due to their tunable bandgap and high efficiency of carrier transport. However, the lack of fully exposed active sites in bulk samples or stacked nanosheets leads to limited performances. In this work, a general method is developed to construct ordered mesoporous TMDs/metal oxides (OM-TMDs/MOs) heterostructures, including WS₂/WO₃, WSe₂/WO₃, WTe₂/WO₃, MoS₂/MoO₃, and V₃S₄/V₂O₃, through one-step thermal sulfurization (selenidation/tellurization) of self-assembled amphiphilic block copolymer/polyoxometalates clusters nanocomposites with ordered mesostructures. The OM-TMDs/MOs possess highly OM structures with high specific surface area, large pore size, and rich active edge sites in the frameworks of heterostructures. The chemiresistive gas sensor based on OM-WS₂/WO₃ shows excellent NO₂-sensing performances at room temperature, with high sensitivity, ultrahigh selectivity ($S_{{\text{NO}}_2}$/S_gas > 20), and fast response speed (6 s). Theoretical study reveals that the strong adsorption capacity of WS₂/WO₃ heterostructure and edge sites of WS₂ for NO₂ molecules and the high charge transfer between them contribute to high selectivity and sensitivity of the sensor. This universal method provides novel strategy for synthesis of OM TMDs-based nanomaterials, showing great potential in various applications such as electronic devices, catalysis, energy storage, and conversions.