Hollow Co ₃ O ₄ microspheres assembled with nanocrystals for non‐enzymatic glucose sensor

Abstract

A non‐enzymatic glucose sensor was developed by using the hollow Co 3 O 4 microspheres assembled with nanocrystals as the sensing materials. The hierarchical structured materials were prepared using carbon spheres as sacrificial templates. X‐ray diffraction, scanning electron microscope and transmission electron microscopy were employed to characterise the crystal structure and morphology of the hollow microspheres. The results showed that the as‐prepared cubic crystalline Co 3 O 4 products have a hollow nature, with the shell thicknesses of about 150 nm. The walls of the hollow microspheres were composed of lots of nanocrystals with diameters about 50 nm. The Co 3 O 4 hollow microspheres displayed superior electrochemical activity used as non‐enzymatic glucose sensors. The high linearity between catalytic current density and glucose concentration was obtained in the range of 2 μM–1.48 mM with a sensitivity of 68.77 μA mM −1 cm −2 . More importantly, the interference from the commonly interfering species such as L‐valine, urea, L‐proline, NaCl and L‐lysine can be effectively avoided. The high sensitivity, low detection limit and good selectivity indicated that the hollow Co 3 O 4 microsphere is a promising no‐enzymatic glucose sensor material for practical application.