Preparation of NiCo2O4 and NiCo2S4 micro-onions for electrochemical sensing of glucose

Abstract

Glucose is an important indicator of life activity. How to quickly and accurately detect glucose concentration is of great significance in life activities. In this study, the Co3O4 micro-balls with onion structure were first grown by a hydrothermal method (160 °C, 4 h). Second, these Co3O4 micro-onions were transformed into Co4S3 micro-onions particles via a second hydrothermal reaction (90 °C, 6 h). Third, Co4S3 was transformed into NiCo2S4 micro-onions via a third hydrothermal process (160 °C, 4 h). The preparation method of NiCo2O4 is similar as the preparation of Co3O4, which extra adds Ni(NO3)2·6H2O in hydrothermal treatment. Compared with NiCo2O4, we find that this micro-onion structure NiCo2S4 glucose sensor shows a high sensitivity of 1.89 mA mM− 1 cm− 2, a fast response time (less than 1.8 s), a low detection limit [2.226 µM (S/N = 3)], and a wide detection range (0.2–2.4 mM). Moreover, the NiCo2S4 electrode exhibits a high selectivity for glucose in human serum, against ascorbic acid and uric acid.