Nonenzymatic glucose‐reactive electrodes fabricated from facilely‐precipitated cobalt hydroxide, commercial graphene nanopowder and ionic liquid binder.

Fine Co(OH)2 powder was prepared by simple precipitation from aqueous solutions of cobalt sulfate and sodium hydroxide without using sophisticated reagents and/or approaches. The fine powder was homogeneously mixed with protonated betaine bis((trifluoromethyl)sulfonyl)amide ionic liquid ([Hbet][TFSA] IL), an amide-type hydrophobic protic IL, and then dispersed in ethanol with graphene nanopowder for being spin-coated upon screen-printed carbon electrode (SPCE) to prepare the glucose-reactive electrode. Activation of the electrode was essential to expose the glucose-oxidation activity, and the experimental evidences indicated that Co3O4 converted from Co(OH)2 during the activation process was the active species in charge of glucose oxidation. The electrode showed a wide linear dynamic range for glucose from 1 to 1757 µM with a high sensitivity of 632 µA cm− 2 mM− 1 and a detection limit of 1 µM in the electrolyte containing 0.5 M NaOH and 0.1 M NaCl. The electrode showed no response to common interferants, including alcohols, in the concentration the same as to glucose. However, ascorbic acid in the same concentration level showed severe interference but negligible in the physiological level. This study shows that Co(OH)2 prepared by facile precipitation is qualified of being an efficient electrocatalyst precursor for glucose oxidation, and IL is a good binder for immobilizing the electrocatalyst. [ABSTRACT FROM AUTHOR]