Solid-contact polymeric membrane ion-selective electrodes based on electrodeposited NiCo₂S₄ nanosheet arrays

Area of Science:

• Electrochemistry
• Materials Science
• Analytical Chemistry

Background:

• Development of stable and reproducible ion-selective electrodes is crucial for accurate electrochemical sensing.
• The interface between the solid contact layer and the sensing membrane significantly impacts electrode performance.
• Hydrophobic properties of solid contact materials can prevent water layer formation, improving electrode stability.

Purpose of the Study:

• To synthesize quasi-superhydrophobic porous NiCo2S4 nanosheet arrays using a facile one-step electrodeposition method.
• To construct and evaluate calcium ion-selective electrodes (Ca2+ -ISE) utilizing the prepared NiCo2S4 as a solid contact layer.
• To investigate the electrochemical performance, stability, and reproducibility of the developed Ca2+ -ISE.

Main Methods:

• One-step electrodeposition of porous NiCo2S4 nanosheet arrays.
• Construction of Ca2+ -ISE with NiCo2S4 as the solid contact layer.
• Electrochemical characterization including Nernstian slope, detection limit, potential stability, and reproducibility measurements.

Main Results:

• The NiCo2S4 nanosheet arrays exhibited quasi-superhydrophobic properties with a large contact angle (148°).
• The fabricated Ca2+ -ISE demonstrated a good Nernstian slope (30.7 mV/dec) and a low detection limit (1.6 × 10^-7 M).
• High potential stability (1.9 ± 0.5 μV/h over 90 h) and excellent batch-to-batch reproducibility (E° standard deviation of 0.7 mV) were achieved.

Conclusions:

• The quasi-superhydrophobic porous NiCo2S4 nanosheet arrays are effective solid contact materials for Ca2+ -ISE.
• The unique surface properties of NiCo2S4 suppress water layer formation, enhancing electrode performance and stability.
• This work presents a promising strategy for developing high-performance ion-selective electrodes.