Mixed Valence Copper Oxide (CuO<i>_x</i>) as Active Catalyst for Glucose Electrochemical Sensor

Abstract Detecting glucose levels in food &amp; 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.