3D-printed Ag/AgCl pseudo-reference electrodes

Three-dimensional (3D) printing offers the advantages of customisation, reproducibility and rapid production. In parallel, there is a demand for electrochemical components designed for miniaturisation or customisation of devices. Herein we report a straightforward, fast and simple method to prepare an Ag/AgCl pseudo-reference electrode primarily based on 3D printing using a graphene/polylactic acid filament. The fabrication process involves electrodeposition of silver followed by bleaching to form AgCl on the surface of the electrode. Scanning electron microscopy and energy dispersive X-ray spectroscopy confirm the fabrication process. Open circuit potential measurements against commercial Ag/AgCl reference electrodes reveal a difference of 14 ± 0.3 mV. Nonetheless, the values are stable and reproducible, fulfilling the necessary requirements of a reference electrode. The performance of the 3D-printed pseudo-reference electrode was tested via cyclic voltammetry in two redox systems, [Fe(CN)₆]^{3 − /4 −} and [Ru(NH₃)₆]^2+/3+. Fabrication of stable 3D-printed reference electrodes represents a key step in the production of fully 3D-printable electrochemical systems.