Stable electrodes are crucial for the creation of high-performance electrochemical microsensors, as they guarantee reliable long-term operation and enhanced sensitivity. Silver electrodes coated with a thin film of silver chloride (AgCl/Ag) form the basis of analytical electrodes due to the excellent charge transfer characteristics and non-polarization of the AgCl material. Also, there is great interest in the integration of nanoparticles with carbon materials due to their unique properties, though challenges related to their hydrophobicity remain. In this study, we modified the silver substrate to create nanostructured reference electrodes and prepared the carbon substrate for the working electrode to improve its compatibility with nanoparticles. The chemical modification process, performed by means of the chlorination of the metal microelectrodes on silicon wafer, included the following steps: degreasing and chemical roughening of the Ag film; washing, drying, and chlorination of the Ag film at room temperature; washing and chemical and thermal stabilization of the nanostructured AgCl film. The enhancement of the hydrophilic properties of nanocrystalline graphite films was achieved by using an acid treatment on the film. The electrodes were structurally characterized, highlighting the formation of the silver chloride film, the degree of purity, and the structural integrity of the carbon material. Microscopic studies allowed us to observed the morphology and roughness of both the modified carbon material and the film, consisting of spherical particles AgCl/Ag with a thickness of about 300 nm. Contact angle analysis was used to investigate the film-wetting properties of the two types of electrodes.

Acknowledgements: This work was supported by a grant from the Ministry of Research, Innovation and Digitization, CNCS-UEFISCDI, project number PN-IV-P2-2.1-TE-2023-0417, within PNCDI IV, and by the Core Program within the National Research Development and Innovation Plan 2022-2027, project no. 2307.