Investigation of sol-gel Synthesized CdO-ZnO Nanocomposite for CO Gas Sensing

A novel CdO-ZnO nanocomposite has been synthesized by a sol-gel pyrrolysis method based on polymeric network of polyvinyl alcohol (PVA). The prepared nanocomposites have been carefully characterized using scanning electron microscopy, X-Ray dispersive energy analysis, ICP-atomic emission spectroscopy and X-Ray diffraction. The obtained results showed that the synthesized nanocomposite at optimum conditions has excellent linear nanoclusters created from nanograins. Each nanograin was made of a CdO core that completely covered by ZnO layers. Each synthesized nanocomposite was used as sensing agent of CO gas. It was found that synthesized CdO-ZnO nanocomposite at 2%wt Zn(NO3)2, 2%wt Cd(NO3)2, 9%wt PVA, mixed solvent of 50:50 ethanol-water at pyrrolysis temperature of 600°C can be used as CO gas sensing agent to exhibit the highest sensitivity for CO at 135°C. The constructed sensor showed a very low detection limit of 2 ppm with the dynamic range of 2 to 500 ppm.