(Digital Presentation) Flexible Electrochemically Reduced Graphene Oxide Sensors for Lead and Cadmium Detection

Abstract

Electrochemically reduced graphene oxide (ERGO) is an excellent sensor material for toxic heavy metal ion detection due to its unique properties. The ERGO combines the conductivity of pristine graphene with oxygen-containing defects that provide active binding sites for ions such as Pb2+ and Cd2+. Sensors can be fabricated directly via electrochemical reduction from graphene oxide (GO) solution. This GO solution can be prepared in bulk by the Hummers method. The ERGO layer thickness can easily be controlled by changing the process parameters during the electrochemical deposition cycle. It can be easily deposited on substrates with varying degree of conductivity including glassy carbon, indium tin oxide on glass, carbon paper, carbon cloth etc. The carbon cloth substrate is particularly interesting in that it is flexible, three-dimensional, conductive and inexpensive. The combination of carbon cloth and ERGO form a sensitive and disposable solution to the simultaneous electrochemical detection of Pb2+ and Cd2+. By using differential pulse anodic stripping voltammetry, ERGO on glassy carbon can detect down to 50 nM of Pb2+ and 100 nM of Cd2+, and could resolve simultaneous oxidation peaks for both ion species. Furthermore, the ERGO-carbon cloth sensor shows vastly improved current response compared to the glassy carbon substrate due to the cloth’s 3D nature and high surface area combined with ERGO’s affinity for heavy metal ions. Therefore, electrochemically reduced graphene oxide and carbon cloth form a promising material combination for heavy metal sensing in water and food products.