Mixed Valence Copper Oxide (CuOx) as Active Catalyst for Glucose Electrochemical Sensor

Detecting glucose levels in food & beverages and body fluids is crucial for health management and disease diagnosis. Developing a highly efficient and durable catalyst is essential for glucose electrochemical sensor. Herein, we reported copper oxides with tuned structure as catalyst for glucose electro-oxidation by simple hydrothermal method. Formaldehyde, trisodium citrate, and ascorbic acid were adopted as reductant for the synthesis of copper oxides. The surface structure and glucose electro-oxidation activity of as-synthesized copper oxides were carefully studied. The surface valence of copper was greatly influenced by the reductant, and the enhanced Cu⁺ content in the surface was believed to account for the improved activity toward glucose electro-oxidation. When using formaldehyde as reductant, the resulted CuO_x-FA exhibited the best activity toward glucose electro-oxidation with the detection limit as low as 0.1 µM and showed a wide linear detection range of 0.1 µM ∼ 1 mM. The CuO_x-FA also showed fast response, good anti-interference ability, and excellent durability, which makes it a promising catalyst for glucose electrochemical sensor.