Humidity‐Enhanced NO₂ Gas Sensing Using Atomically Sharp Edges in Multilayer MoS₂

Ambient humidity poses a significant challenge in the development of practical room‐temperature NO₂ gas sensors. Herein, atomically precise zigzag edges are employed in multilayer MoS₂, fabricated using electron beam lithography and anisotropic wet etching, to achieve highly sensitive and selective gas‐sensing performance, that is, humidity‐tolerant at elevated temperatures and humidity‐enhanced at room temperature under ultraviolet illumination. Notably, exposure to 2.5 parts per billion (ppb) NO₂ at 70% relative humidity under ultraviolet illumination and at room temperature resulted in a 33‐fold increase in response and a 6‐fold faster recovery compared to 0% relative humidity, leading to response values exceeding 1100%. The optimized samples demonstrate a theoretical detection limit ranging from 4 to 400 parts per trillion (ppt) NO₂. The enhanced NO₂ sensing capabilities of MoS₂ edges have been further confirmed through first‐principles calculations. This study expands the applications of nanostructured MoS₂ and highlights its potential for detecting NO₂ at sub‐ppb levels in complex scenarios, such as high‐humidity conditions.