Topotactic Conversion of Copper(I) Phosphide Nanowires for Sensitive Electrochemical Detection of H₂O₂ Release from Living Cells

In this work, we clearly demonstrate for the first time the use of transition-metal phosphides to set up a new cathodic analysis platform for sensitive and selective electrochemical nonenzymatic detection of H₂O₂. With the help of a facile topotactic conversion method, the noble metal-free electrocatalyst of copper(I) phosphide nanowires on three-dimensional porous copper foam (Cu₃P NWs/CF) is fabricated with electrochemical anodized Cu(OH)₂ NWs as precursor. The Cu₃P NWs/CF-based sensor presents excellent electrocatalytic activity for H₂O₂ reduction with a detection limit of 2 nM, the lowest detection limit achieved by noble-metal free electrocatalyst, which guarantees the possibility of sensitive and reliable detection of H₂O₂ release from living tumorigenic cells, thus showing the potential application as a sensitive cancer cell detection probe.