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

• Published in: Electrochemistry communications 2019-11, Vol.108, p.106562, Article 106562
• Main Authors: Karunadasa, Kohobhange S.P., Manoratne, C.H., Pitawala, H.M.T.G.A., Rajapakse, R.M.G.
• Format: Article
• Language: English
• Subjects: Composite electrode; Electrochemical applications; Enhanced thermal stability; Graphite; Montmorillonite
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2019.106562

[Display omitted] •Graphite–MMT composite electrodes (G-MMTCE) are stable in both molten salts and aqueous electrolytes.•Resistivity of G-MMTCE series decreases exponentially with increasing graphite content.•Flexural strength of G-MMTCE series increases linearly with increasing graphite content.•Lamella-like arrangement of graphite sheets accounts for enhanced electrical and mechanical stability.•G-MMTCE is a potential working electrode for analyte detection and electropolymerization. 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.