molybdenum electrode is a common type of metal used as an anode in microbial fuel cell (MFC) for its high oxidation resistance, long life and corrosion-resistance. However, molybdenum is an active oxidant that can produce a large amount of reactive oxygen species and eventually lead to deterioration of the electrode.
The sensitivity, selectivity and lifetime of molybdenum electrode are highly dependent on the electrode material and the cation and anion concentrations. The electrode has good selectivity against Cl-, Br-, NO- 3, H2PO- 4, SO2- 4 anions and a few cations such as K+, Na+, Cu2+, Ag+ and Ca2+.
In this work we studied the influence of a number of interfering ions on the pH dependence of a molybdenum ion selective electrode prepared from solid salts of 20% MoS2, 60% Ag2S and 20% Cu2S. The interfering ions were added into 0.1 M NaNO3 with 10-5 M molybdenum solution, and the potential change was measured after each addition.
Results: The electrode showed a small interference effect for the anions. No interference was observed for the cations except for bromide, which was slightly affected. The sensitivity of this molybdenum electrode was 45 +- 2 mV/decade.
The use of 2D/3D molybdenum disulfide (MoS2)-based chemically modified electrodes as electrochemical sensors is a promising approach to detect and analyze biomolecules and hazardous chemicals. Hydrothermal, mechanical and ultrasonic techniques have been developed to synthesize graphene-like MoS2 nanostructures for electrochemical applications. These materials exhibit unique physicochemical properties that can improve the sensing performance of enzyme-based amperometry, chemiluminescence and nucleic acid sensors.