A novel electrochemical sensor based on HER overpotential of Ag-Cu bimetallic catalyst

Conventional electrochemical (EC) sensors usually rely on modifying redox substances to generate signal, which may lead to the requirement of complex modification processes and abnormal signal fluctuation. In addition, many redox substances would cause potential risks to the environment. To solve these issues, a novel environmentally friendly electrochemical sensor based on hydrogen evolution reaction (HER) was established, and the overpotential of Ag-Cu bimetallic HER catalyst was used as signal to avoid using redox substances. As a proof of concept, a model tumor marker, matrix metalloproteinase-3, was detected by this sensor with a wide linearity ranging from 0.001 to 100 ng mL−1 and a low limit of detection of 2.02 fg mL−1. These results illustrated great sensing performances. This method provided a new direction in designing novel eco-friendly EC sensors and application of HER catalysts.