1T/2H-MoS2 engineered by in-situ ethylene glycol intercalation for improved toluene sensing response at room temperature

Synergically engineering defect and interlayer in SnS2 for enhanced room-temperature NO2 sensing

Defect and interlayer engineering are considered as two promising strategies to alter the electronic structures of sensing materials for improved gas sensing properties. Herein, ethylene glycol intercalated Al-doped SnS₂ (EG-Al-SnS₂) featuring Al doping, sulfur (S) vacancies, and an expanded interlayer spacing was prepared and developed as an active NO₂ sensing material. Compared to the pristine SnS₂ with failure in detecting NO₂ at room temperature, the developed EG-Al-SnS₂ exhibited a better conductivity, which was beneficial for realizing the room-temperature NO₂ sensing. As a result, a high sensing response of 410% toward 2 ppm NO₂ was achieved at room temperature by using the 3% EG-Al-SnS₂ as the sensing material. Such outstanding sensing performance was attributed to the enhanced electronic interaction of NO₂ on the surface of SnS₂ induced by the synergistic effect of Al doping, S vacancies, and the expanded interlayer spacing, which is directly revealed by the in-suit measurement based on near-ambient pressure X-ray photoelectronic spectroscopy (NAP-XPS). Furthermore, to identify the role of Al doping, S vacancies, and the expanded interlayer spacing in enhancing the NO₂ sensing properties, a series of comparative experiments and theoretical calculations were performed.

Advanced Strategies to Improve Performances of Molybdenum-Based Gas Sensors

Molybdenum-based materials have been intensively investigated for high-performance gas sensor applications. Particularly, molybdenum oxides and dichalcogenides nanostructures have been widely examined due to their tunable structural and physicochemical properties that meet sensor requirements. These materials have good durability, are naturally abundant, low cost, and have facile preparation, allowing scalable fabrication to fulfill the growing demand of susceptible sensor devices. Significant advances have been made in recent decades to design and fabricate various molybdenum oxides- and dichalcogenides-based sensing materials, though it is still challenging to achieve high performances. Therefore, many experimental and theoretical investigations have been devoted to exploring suitable approaches which can significantly enhance their gas sensing properties. This review comprehensively examines recent advanced strategies to improve the nanostructured molybdenum-based material performance for detecting harmful pollutants, dangerous gases, or even exhaled breath monitoring. The summary and future challenges to advance their gas sensing performances will also be presented.