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 ((NH 4 ) 2 MoS 4 /(NH 4 ) 2 WS 4 ) with polyoxometalate (POMs) clusters as dual inorganic precursors. Through solvent evaporation‐induced self‐assembly (EISA) followed by thermal treatment, mesoporous WS 2 /WO 3 , WS 2 /MoO 3 , MoS 2 /WO 3 , and MoS 2 /MoO 3 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 WS 2 /WO 3 heterostructures demonstrate exceptional room‐temperature NO 2 sensing performance, surpassing that of their single‐component counterparts (mesoporous WS 2 or WO 3 ). 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).