Rational Construction of a Cu-Cu₂O-CuHCF Heterojunction Interface for High-Performance Potassium-Ion Sensing.

Area of Science:

• Electrochemistry
• Materials Science
• Sensor Technology

Background:

• Potassium ion (K+) sensors face limitations in high-temperature applications due to the thermal instability of traditional ionophores.
• Existing sensors degrade above 50 °C, restricting their use in marine, energy storage, and industrial environments.

Purpose of the Study:

• To develop a robust, all-solid-state potassium ion (K+) sensor with enhanced thermal stability for demanding applications.
• To investigate the K+ selectivity and performance of a novel Cu-Cu2O-CuHCF heterojunction sensor.

Main Methods:

• Utilized first-principles density functional theory (DFT) for rational sensor design and K+ selectivity prediction.
• Employed a one-step electrochemical synthesis to fabricate the Cu-Cu2O-CuHCF heterojunction.
• Characterized the sensor using electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and scanning electron microscopy (SEM).

Main Results:

• The developed sensor operates effectively in a wide temperature range (25-100 °C) with high K+ selectivity, even in high-salinity seawater.
• DFT calculations accurately predicted superior K+ over Na+ selectivity based on adsorption energetics.
• A machine learning model (PTC) was developed to correlate potential, temperature, and concentration for practical field deployment.

Conclusions:

• The Cu-Cu2O-CuHCF heterojunction sensor offers a breakthrough solution for K+ sensing in harsh, high-temperature environments.
• This work establishes a new approach for designing robust electrochemical sensors by integrating theoretical design and machine learning.
• The developed sensor and predictive model pave the way for advanced applications in marine resource utilization, energy storage, and industrial process monitoring.