Direct formation of (Co, Mn)3O4 nanowires/Ni composite foam for electrochemical detection

• The 3D (Co, Mn)3O4 nanowires/Ni composite foam was successfully synthesized through a facile method.
• The composite foam was directly applied as the electrode for heavy metal sensor.
• The (Co, Mn)3O4 nanowires/Ni composite foam electrode exhibited high cycling stability and long-term durability.

The three dimensional (Co, Mn)3O4 nanowire array grown on Ni foam (3D (Co, Mn)3O4 nanowires/Ni composite foam) were successfully synthesized through a one-step hydrothermal approach and then directly applied as the electrode for heavy metal sensor. The structure of (Co, Mn)3O4 nanowires/Ni composite foam was characterized by the X-ray power diffraction (XRD), Scanning electronic microscopy (SEM) and Raman spectrum. Additionally, serving as a Hg(II) sensor, the (Co, Mn)3O4 nanowires/Ni composite foam electrode exhibited remarkable electrocatalytic activity towards Hg(II) oxidation with high limit of detection and sensitivity of 0.013 μM and 6.91 μA/μM, respectively. Furthermore, the (Co, Mn)3O4 nanowires/Ni composite foam electrode for sensor exhibited high cycling stability and long-term durability. These results are attributed to the unique features of the (Co, Mn)3O4 nanowires/Ni composite foam electrode, which enables the surface of (Co, Mn)3O4 nanowires grown on Ni foam to become highly accessible to the metal ion and provides more void volume for the reaction with metal ion. This work suggests that there is great potential in employing the 3D (Co, Mn)3O4/Ni composite foam as heavy metal ions sensors.