Electrochemical Biosensor Based on Nanoporous Au/CoO Core-Shell Material with Synergistic Catalysis

An ultrathin CoO layer is deposited on the skeleton surfaces of a nanoporous gold (NPG) film by using atomic layer deposition, creating a flexible electrode. Detailed characterization demonstrates the superior performance of the flexible NPG/CoO hybrids for electrochemical catalysis. The NPG/CoO hybrid not only achieves high catalytic activity for glucose oxidation and H2O2 reduction, but also exhibits a linear dependence of the electrical signal on the concentration of glucose and H2O2 molecules in the electrolyte. Meanwhile, the sensitivity for H2O2 reduction can be as high as 62.5Amm(-1)cm(-2) with linear dependence on the concentration in the range of 0.1-92.9mm. The high sensitivity is proposed to result from the synergistic effect of Au and CoO at the interfaces, and the high conductivity of the gold skeleton with a large surface area. The superior electrochemical performance of this hybrid electrode is promising for future potential applications in various transitional-metal-oxide-based electrochemical electrodes.