High performance electrochemical L-cysteine sensor based on hierarchical 3D straw-bundle-like Mn-La oxides/reduced graphene oxide composite

A novel 3D straw-bundle-like Mn-La oxides/reduced graphene oxide composite (Mn-La oxides/rGO) has been successfully synthesized by a facile thermal evaporation method. The products were investigated by means of scanning electron microscopy (SEM), energy dispersive X-ray spectrum (EDS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical method. The passible growth mechanism was tentatively proposed. The application of the 3D straw-bundle-like Mn-La oxides/rGO as electrode-modified material for electrochemical oxidation of L-cysteine was studied. The prepared Mn-La oxides/rGO modified electrode expressed prominent electrocatalytic ability for the electrochemical oxidation of L-cysteine. Under optimum experimental conditions, the current response of L-cysteine were linear with its concentration in the range of 0.5-832.5 mu M with a low detection limit of 0.1 mu M (S/N = 3). The proposed sensor was used to evaluate its application for the detection of L-cysteine in the real samples.