Ternary Co‐Assembly Synthesis of Mesoporous Transition Metal Dichalcogenides/Oxides Heterostructures for Synergistically Enhanced Room‐Temperature Chemiresistive Sensors

Constructing transition metal dichalcogenides/oxides (TMDs/TMOs) heterostructures is an effective strategy to enhance their functional properties through band coupling and carrier migration. Furthermore, introducing a mesoporous architecture into TMDs/TMOs can significantly improve their porosity and specific surface area, thereby boosting their performance in chemical sensing, energy storage/conversion, and catalysis. However, it remains a significant challenge to realize a direct and facile synthesis of mesoporous TMDs/TMOs (mTMDs/TMOs) heterostructures with tunable compositions and abundant heterogeneous interfaces. In this work, a one-pot ternary co-assembly approach is presented to synthesize mTMDs/TMOs heterostructures. This approach utilizes amphiphilic block copolymer PEO-b-PS as a structure-directing agent and ammonium thiometallates ((NH₄)₂MoS₄/(NH₄)₂WS₄) with polyoxometalate (POMs) clusters as dual inorganic precursors. Through solvent evaporation-induced self-assembly (EISA) followed by thermal treatment, mesoporous WS₂/WO₃, WS₂/MoO₃, MoS₂/WO₃, and MoS₂/MoO₃ with precisely tunable TMDs/TMOs ratios, highly crystalline frameworks, and rich heterointerfaces, are successfully fabricated. As a proof of concept, chemiresistive gas sensors based on mesoporous WS₂/WO₃ heterostructures demonstrate exceptional room-temperature NO₂ sensing performance, surpassing that of their single-component counterparts (mesoporous WS₂ or WO₃). Such enhancement arises from the synergistic effects of the heterostructure and mesoporous structures that yield abundant gas adsorption sites and efficient molecular diffusion within the interconnected mesopores (2-50 nm).