Although ZnO nanostructures gas sensors have been widely used in practice, the high working temperature10,11 and complex structures12 is undesirable for wearable electronic devices. In order to apply to wearable electronic devices, the gas sensor needs flexible, transparent, and working at room temperature, which are not available for traditional gas sensors. Therefore, developing the new generation of flexible, transparent and room temperature working gas sensor is a quite attractive and challenge task.