SnO2/graphene nanocomposite for effective detection of CO at room temperature

•At present, most CO sensors possess high operation temperature, high power consumption and low stability. We proposed a high-performance CO sensor at room temperature.•The SnO2/graphene nanocomposite exhibits unique morphology with SnO2 nanoparticles dispersing in graphene nanosheets, which exerts a great effect on in improving sensing performance of CO.•The sensor shows improved CO gas response (R≈5.9 at 40 ppm CO) compared with pure SnO2 (R≈3.27 at 40 ppm CO). Moreover, the sensor also exhibits fast response and recovery time (37 s/43 s).