The nanostructured Au-doped cobalt oxyhydroxide based carbon monoxide sensor for fire detection at its earlier stages

摘要

Two nanostructures of cobalt oxyhydroxide (CoOOH) and Au-loaded CoOOH with amount of Au (0.05, 0.5 and 1 mass(percent)), respectively, were investigated for gas sensing properties to combustion by-product pollutants, which are typical for early stages of fire. The nanostructured p-type semiconductor films have shown good sensitivity to carbon monoxide (CO) in the temperature range 50-110 deg C with the maximum sensitivity to CO at 80 deg C. As the amount of Au-load increased to 0.5 mass(percent), the improvement in both CO sensitivity and response/recovery rates has been established. The additional increase of the Au-load up to 1 mass(percent) degraded the CO sensing properties of the device. Cross-sensitivity investigation of the sensor to various gases co-existing at the earlier stages of fire revealed that CO sensitivity of nanostructured Au-loaded CoOOH is the highest among other gases. The morphologies of the prepared Au-doped CoOOH samples have been studied by x-ray diffraction (XRD), energy-dispersive x-ray diffraction (EDX) and scanning electron microscopy (SEM) techniques. The promoting effects of Au loads were discussed. The results of this work may be applicable for further development of carbon monoxide sensors for fire detection at its earlier stages.