Highly selective non-enzyme glucose detection based on Co-CoO-Co3O4 nanocomposites prepared via a solution-combustion and subsequent heat-treating route

Co-based compounds, especially cobalt oxides, have been widely employed as the non-enzyme catalysts for the electro-oxidation of glucose. In this work, we designed a solution-combustion and subsequent heat-treating route to successfully prepare Co-CoO-Co 3 O 4 nanocomposites. Co-CoO nanocomposites were first obtained in one step via a simple solution-combustion method, employing CoCl 2 as the Co source, oxygen in air as the oxygen source, and ethanol as the solvent and fuel; and then, the freshly-prepared Co-CoO nanocomposites were annealed in air at 300–600 °C for 2 h. Experiments showed that the annealing temperature strongly affected the component of the final product. Co-CoO-Co 3 O 4 nanocomposites were produced at 300 and 400 °C; CoO-Co 3 O 4 nanocomposites were obtained at 500 °C; and Co 3 O 4 nanoparticles were formed at 600 °C. The above annealed products were labeled as T3, T4, T5 and T6. Electrochemical measurements showed that Co-CoO nanocomposite and its annealed products presented good electrochemical properties and could be employed as catalysts for the non-enzyme electro-oxidation of glucose. Among them, T4 sample (Co-CoO-Co 3 O 4 nanocomposites) possessed the best electrocatalytic activity. The as-prepared T4/GCE sensor showed rapid response time (<1s), high sensitivity (949.3 μA mM −1  cm −2 ), long linear range (0.005–0.6, 0.6–4.3 mM), low detection limit (0.92 μM), and good stability and selectivity.