Self-Assembled Co <sub>3</sub> O <sub>4</sub> /GO Composites for Excellent Electrochemical Detection of Heavy-Metal Ions
Yachao Hao, Chong Zhang, Wentao Wang, Jing Wang, Shuhang Chen, Hongyan Xu, Serge Zhuiykov
Abstract
Recently, electrochemical sensors have been applied for the detection of heavy metal ions. The modifier on the electrochemical electrode is the key factor for enhanced performance. Modification by combining metal oxide nanomaterials with good adsorption property and graphene oxide (GO) with good conductivity can construct a useful sensing interface to detect heavy metal ions. Here, the effects of structures and morphologies of Co 3 O 4 /GO composite modifiers on the electrochemical detection performance were studied. The results show that Co 3 O 4 /GO composite with holey nano-sheets of pure Co 3 O 4 on lamella GO substrate had the best electrochemical performance for their large active sites and enhanced ion and charge transports. The limits of detection of the electrochemical sensors based on developed Co 3 O 4 /GO composite to Cd 2+ and Pb 2+ were calculated as 57 and 29.4 nM, respectively, which are lower than the guideline values recommended by the World Health Organization for drinking water. Furthermore, the designed sensor also showed excellent stability, selectivity, and acceptable reproducibility and reliablity. The results indicate that Co 3 O 4 /GO composite with holey layer structures as a promising electrode modifier could be potentially applied in the electrochemical detection of heavy metal ions on-site.