A solid-contact potassium-selective electrode with MoO₂ microspheres as ion-to-electron transducer.

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Solid-contact ion-selective electrodes (SC-ISEs) are crucial for electrochemical sensing.
• Developing efficient ion-to-electron transducers is key to improving SC-ISE performance.
• Molybdenum dioxide (MoO₂) has potential as a novel transducer material.

Purpose of the Study:

• To synthesize and characterize MoO₂ microspheres for use as an ion-to-electron transducer in SC-ISEs.
• To fabricate and evaluate a novel SC-ISE for potassium ion (K⁺) detection utilizing MoO₂ microspheres.
• To investigate the electrochemical properties and stability of the developed SC-ISE.

Main Methods:

• Synthesis of MoO₂ microspheres via reduction of MoO₃ nanobelts.
• Characterization of MoO₂ microspheres using X-ray diffraction and field-emission scanning electron microscopy.
• Fabrication and electrochemical testing of the SC-ISE, including potentiometric measurements, impedance spectroscopy, and chronopotentiometry.

Main Results:

• Successfully synthesized and characterized MoO₂ microspheres with desirable properties.
• The fabricated SC-ISE demonstrated a stable and rapid potential response for K⁺.
• A near Nernstian slope of 55 mV/decade was achieved in the 10^-5–10^-3 M range, with a detection limit of 10^-5.5 M.
• Introduction of MoO₂ microspheres reduced resistance and increased capacitance, enhancing electrode performance.
• The SC-ISE showed good stability against environmental factors like light, O₂, and CO₂.

Conclusions:

• MoO₂ microspheres are effective ion-to-electron transducers for SC-ISEs.
• The developed SC-ISE offers a promising platform for sensitive and stable potassium detection.
• MoO₂ microspheres represent a viable alternative to traditional transducing layers in electrochemical sensors.