Investigation on morphologies and supporter of cerium dioxide nanostructure on oxime based electrochemical sensors for organophosphorus detection

Pralidoxime (PAM) chloride has been taken as be an effective electrochemical probe to detect organophosphorus pesticides (OPs). In our previous work, CeO2 nanoparticles were proved to be able to significantly improve the sensitivity of the as-fabricated electrochemical sensor. In this paper, PAM-based sensors with different morphologies and supporters of nano-structured CeO2 were investigated. Firstly, CeO2 particles, CeO2 cubes and CeO2 rods were prepared and characterized. The results show that the CeO2 rods exhibits the best electrochemical performance because of its larger specific surface and better electrocatalytic activity. Secondly, multiwalled carbon nanotubes (MWCNTs), carbon powder (CP) and Carbon aerogel (CA) were adopted as supporter to disperse CeO2 rods. The results show that CA with large specific surface area and excellent adsorption property makes the fabricated sensor exhibit the best performance. Under the optimized conditions, the sensor has a chlorpyrifos detecting limit of 3.4 x 10-12 M in the range from 5 x 10-11 M to 1 x 10-7 M. Besides, the sensor also shows good repeatability, stability and reliability in the detection of chlorpyrifos.