Enhanced free radical generation on MoS 2 /Pt by light and water vapor co-activation for selective CO detection with high sensitivity.

Semiconductor-based gas sensors hold great promise for effective CO detection. However, boosting sensor response and selectivity remains a key priority in moist conditions. In this study, w e developed a composite material, Pt quantum dots (QDs) decorated MoS 2 nanosheets (MoS 2 /Pt), as a highly sensitive material for CO detection when facilitated with visible light. The MoS 2 /Pt sensor showed 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 has been confirmed both experimentally and theoretically that the MoS 2 /Pt surface lowers the activation energy to convert CO to CO 2 via the free radicals induced by the synergy of photochemical effects and water vapor. As a result, the MoS 2 /Pt surface promotes both CO response and selectivity, providing fundamental clues to improve room temperature semiconductor-based sensors for gas detection under extreme conditions. This article is protected by copyright. All rights reserved.