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

Graphical This study reports a simple hydrothermal method for synthesizing copper oxides (CuO x ) with varied Cu + /Cu 2+ ratio. It turns out that the surface Cu + species are highly active sites for glucose electro-oxidation. The glucose electrochemical sensor using as-synthesized CuO x -FA as catalyst exhibits wide detection range with low detection limit and quick response. 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.