| 초록 |
Volatile organic compounds (VOCs) such as C2H5OH, xylene, and toluene are harmful for human health and hence it is important to detect ppm level of VOCs. Porous Co3O4 spheres were synthesized by ultrasonic spray pyrolysis and their VOC sensing characteristics were investigated. Decomposition of polyethylene glycol (PEG) in the precursor played an important role for the formation of bimodal pores (size: 2-3 nm and ~30 nm) in porous Co3O4, since only monomodal pores (size: 2-3 nm) were remained in dense Co3O4 spheres without PEG in spray solution. The responses of porous Co3O4 spheres to various VOCs, such as 5 ppm C2H5OH, xylene, toluene, benzene, and HCHO at 200°C were significantly higher than those of dense and commercial Co3O4 powders. Enhanced gas response of porous Co3O4 spheres is attributed to high surface area and the effective diffusion of analyte gases through mesopores (~30 nm). |
