Easy preparation of cobalt oxide/copper oxide composites for gas sensing application

This paper describes the preparation of Co3O4/CuO composites with vary CuO contents (Co3O4/CuO = 1.0wt%/0.50-1.0wt%) using a simple sol-gel process. According to SEM analysis, the composite samples exhibit a round-like morphology. XRD analysis revealed the formation of CuxCoyOz mixed oxide nanostructures. The composite materials were tested as thick films in conductometric devices for ammonia gas sensing at the optimal temperature of 150 °C. The response of Co3O4/CuO (1.0wt%/1.0wt%) composite was found much higher compared to pure Co3O4 and CuO NPs, suggesting that a synergic interaction occurs between the two metal oxide components in improving ammonia gas sensing capability. According to the findings reported, the design of Co3O4/CuO composite heterojunctions by the simple sol-gel process adopted might be an effective way to increase gas sensing toward ammonia gas at mild temperature.