Tuning of Co3X4 (X = O, S, Se) by anion substitution for highly electrochemical sensing of glucose

Cobalt (Co) based nanomaterials are widely used to construct glucose enzyme-free electrochemical sensors. However, the correlation between anion species and the electrocatalytic activity of Co based nanomaterials remains unproven. In this paper, Co3X4 with different anions (X = O, S, Se) were synthesized for electrochemical sensing of glucose. Co3X4 was characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDX), powder X-ray diffractometry (XRD), and electrochemical techniques. The results showed that anion substitution had a significant effect on the electrocatalytic properties of Co3X4, and Co3Se4 showed the strongest electrocatalytic activity for the oxidation of glucose. The sensor based on Co3Se4 exhibited excellent performance for glucose analysis with a linear range from 2 mu M to 0.71 mM, a high sensitivity of 1327.6 mu A mM-1 cm-2 and a low detection limit of 0.3 mu M, which demonstrates Co3Se4 as a new nonenzymatic electrocatalyst for glucose sensing.