Hydrous Cerium Dioxide-Based Materials as Solid-Contact Layers in Potassium-Selective Electrodes.

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Metal oxides are suitable for solid-contact layers in potentiometric sensors due to redox activity and large surface area.
• Hydrous cerium dioxide (hCeO2) is explored as a novel material for solid-contact layers.
• Composite materials incorporating hCeO2 with nanomaterials or conducting polymers are investigated.

Purpose of the Study:

• To evaluate hydrous cerium dioxide as a solid-contact layer in ion-selective electrodes.
• To assess the impact of hCeO2 on the microstructure, wettability, and electrical properties of sensor materials.
• To develop a facile and rapid method for preparing hCeO2-based potentiometric sensors for potassium determination.

Main Methods:

• Synthesis and characterization of standalone and composite hCeO2 materials (hCeO2-nanotubes, hCeO2-conducting polymer).
• Testing of three hCeO2-based materials as solid-contact layers in potentiometric sensors.
• Evaluation of sensor performance including electrical capacitance, contact angle, linear range, potential stability, and pH tolerance.

Main Results:

• hCeO2 addition enhanced electrical capacitance (798 μF for hCeO2-NTs, 112 μF for hCeO2-POT) and contact angle (100° for hCeO2-NTs, 120° for hCeO2-POT).
• The sensor preparation method is simple, fast (within an hour), and requires no specialized equipment.
• hCeO2-based electrodes demonstrated a competitive linear range and stable potential across a wide pH range (2.0-11.5).

Conclusions:

• Hydrous cerium dioxide is a promising material for solid-contact layers in ion-selective electrodes.
• hCeO2 enhances the electrochemical and surface properties of sensor materials.
• The developed hCeO2-based electrodes are suitable for reliable potassium determination in environmental and clinical samples.