CuO modified Si nanowires for enzyme-free photoelectrochemical sensing of H2O2

Constructing novel hybrid nanostructure has become an effective strategy to enhance the performance of photoelectrochemical (PEC) biosensors. However, most of the H2O2-sensing photoelectrodes require enzyme modification, which limits the working environment and sensing performance. Herein, the burr-like CuO nanostructures are modified on the entire surfaces of the ordered Si nanowires (SiNWs) by using a combination of magnetron sputtering and hydrothermal growth. The optimized CuO@SiNWs heterojunction with a core-shell structure enables enzyme-free PEC detection of H2O2, achieving a sensitivity of 227.76 μAmM-1cm-2 in the concentration range of 0–588 mM and a detection limit of 7.14 μM (Signal/Noise=3). The excellent sensing performance of the CuO@SiNWs is attributed to the large specific surface area provided by SiNWs and the CuO possess desired H2O2-catalytic activity while providing a great number of active sites. In addition, the CuO@SiNWs demonstrates satisfactory optical absorption. This work demonstrates that enzyme-free and highly sensitive H2O2 detection can be achieved by hybrid nanostructure, providing an alternative route to H2O2 sensing.