A freestanding all-solid-state polymeric membrane Cu-selective electrode based on three-dimensional graphene sponge.

A novel freestanding all-solid-state polymeric membrane Cu-selective electrode (Cu-ISE) is proposed based on three-dimensional graphene sponge (3D GS). The 3D GS electrode has been characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and contact angle measurements. Experiments show that 3D GS possesses a large electrical double layer capacitance, good conductivity, and high hydrophobicity. Based on these superior properties, 3D GS has been applied as both electrode substrate and solid contact for construction of a freestanding all-solid-state polymeric membrane Cu-ISE. The 3D GS-based Cu-ISE shows a good Nernstian response ranging from 1.0 × 10 to 7.9 × 10 M with a low detection limit of 2.5 × 10 M. Moreover, the proposed Cu-ISE exhibits a stable potential response with a reduced water layer at the sensing membrane/3D GS interface and is not affected by interferences from light, O and CO.