A potential working electrode based on graphite and montmorillonite for electrochemical applications in both aqueous and molten salt electrolytes

Abstract

The feasibility of a novel graphite–MMT composite electrode for electrochemical processes in aqueous and molten salt electrolytes has been investigated. The graphite–MMT composite electrodes (G-MMTCEs) were fabricated by preparing composites in deionized water, pressing the dry composite under 1.03 × 104 N ram force to obtain cylindrical electrodes (5.00 cm long and 1.00 cm in diameter) and firing the electrodes at around 550 °C for 1 h. The results indicate that the G-MMTCE containing 80% graphite showed the lowest resistivity (8.17 × 10−4 Ωm) and highest flexural strength (5.81 × 106 Nm2). The exponential decrease in resistivity from low to high graphite percentage is clearly observed for a series of G-MMTCEs. The lamella-like graphite structure held together by tiny clay particles accounts for the enhanced electrical and mechanical stability of the G-MMTCEs. It is also found that the fabricated G-MMTCE is very stable in molten salts as well as in aqueous electrolytes with different pH values. The G-MMTCE has advantages as a working electrode over a glassy carbon electrode (GCE) in analyte detection as well as in electropolymerization. A narrow working potential range and enhanced sensitivity are the major advantages of the G-MMTCE over the GCE under identical cell and measurement conditions. Keywords: Graphite, Montmorillonite, Composite electrode, Enhanced thermal stability, Electrochemical applications