In consideration of the different electron structure-associated physical properties and internal sensing merits of MoS 2 and SnO 2 , this work reports a nanocomposite with unique structure of MoS 2 nanosheets dispersed SnO 2 nanoparticles. The sensing performance of MoS 2 /SnO 2 sensor toward low concentration CO was investigated at room temperature under the UV light illumination. It was found that MoS 2 /SnO 2 sensor shows improved CO gas response (R ~ 4.97 at 40 ppm CO) compared with pure SnO 2 (R ~ 3.27 at 40 ppm CO), which is due to the unique structure and the formation of heterostructure between MoS 2 and SnO 2. Moreover, the fabricated sensor also exhibits fast response and recovery time (43 s/36 s). The sensor provides a potential platform for monitoring CO gas at room temperature. [ABSTRACT FROM AUTHOR]