Enhanced Free-Radical Generation on MoS<sub>2</sub> /Pt by Light and Water Vapor Co-Activation for Selective CO Detection with High Sensitivity.

Xia, Yi; Guo, Shenghui; Yang, Li; He, Sufang; Zhou, Liexing; Wang, Mingjun; Gao, Jiyun; Hou, Ming et al. · Adv Mater · 2023

basic_science · Level V

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Abstract

Semiconductor-based gas sensors hold great promise for effective carbon monoxide (CO) detection. However, boosting sensor response and selectivity remains a key priority in moist conditions. In this study, a composite material, Pt quantum dots decorated MoS<sub>2</sub> nanosheets (MoS<sub>2</sub> /Pt), is developed as a highly sensitive material for CO detection when facilitated with visible light. The MoS<sub>2</sub> /Pt sensor shows a significantly improved response (87.4%) with impressive response/recovery kinetics (20 s/17 s), long-term stability (60 days), and good selectivity to CO at high humidity (≈60%). It is confirmed both experimentally and theoretically that the MoS<sub>2</sub> /Pt surface lowers the activation energy to convert CO to CO<sub>2</sub> via the free radicals induced by the synergy of photochemical effects and water vapor. As a result, the MoS<sub>2</sub> /Pt surface promotes both CO response and selectivity, providing fundamental clues to improve room-temperature semiconductor-based sensors for gas detection under extreme conditions.