Engineering Co3O4 with Co defects for highly sensitive nonenzymatic detection of glucose

Abstract

Defect engineering was considered as an effective strategy to regulate electrocatalytic activities of transition metal oxides. However, there are seldom reports about metal defects in electrochemical sensing. In this work, Co-defected Co3O4 was synthesized via thermal treatment of glycerolatocobalt (CoGly) precursor for constructing a novel electrochemical nonenzymatic glucose sensor. The obtained nanomaterials were characterized by transmission electron microscopy (TEM), powder X-ray diffractometry (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. The presence of Co defects regulated electronic structure of Co3O4, which not only speeds up electron transfer rate but also exposes more high-valent Co sites, thus improving electrocatalytic activities. Under optimized conditions, Co-defected Co3O4 electrode exhibited excellent performance for glucose analysis with a wide linear range of 0.2 µM to 0.5 mM, a low detection limit of 0.16 µM. Importantly, an ultrahigh sensitivity of 2595.7 µA·mM−1·cm−2 was also obtained, which was about 10 times higher than that of conventional Co3O4. Therefore, engineering Co3O4 with Co defects is an effective strategy to tailor electrocatalytic activity, which sheds light on the potential applications of metal defects in the field of electrochemical nonenzymatic sensing.