A new method to produce graphite decorated by electrodeposited metal: The case of silver electrodeposition process inside a graphite paste electrode

The results reported in this paper deal with the investigation of the silver electrodeposition process inside a modified graphite paste (MGP). Thus, a new method to produce graphite decorated with electrodeposited metal was proposed that could be used in modified electrodes with renewable surface by polishing. The electrodeposition process was made inside of the MGP (graphite, AgNO3, NaCl and mineral oil) inserted in the tip of a polypropylene syringe with copper wire electrical contact (working electrode, MGPE). Voltammetric study with the MGPE in NaCl aqueous solution indicated that the silver reduction occurred by two different processes at potentials more negative than 0.000 V and −0.150 V and exhibited one anodic peak for silver oxidation. These cathodic processes were dependents of the AgNO3 concentration and NaCl added. It was concluded that the silver reduction occurs mainly in the nearest layer of the MGP/NaCl solution interface, decreasing in direction to the MGP interior. Scanning electron microscopy (SEM) photographs indicated that the silver electrodeposition occurred on some graphite flakes with a homogeneous silver layer, showing also additional morphological features depending on the electrodeposition condition. Transmission electron microscopy (TEM) image showed nanometric electrodeposited silver. X-ray diffraction (XRD) analysis showed diffraction lines for polycrystalline silver. [Display omitted] •Graphite decorated with electrodeposited silver was prepared.•A new method to produce graphite decorated with electrodeposited metal was proposed.•Silver electrodeposition was made inside a graphite paste electrode.•The electrochemical results show the feasibility of the electrodeposition method.