Cu-Cu₂O-CuHCF heterojunction electrode

Stable up to 100 °C

A heterojunction interface with Cu2O transducing layer and K-CuHCF active layer that retains high K+ selectivity at elevated temperatures, overcoming thermal instability of conventional ionophores above 50°C.

Meng, Ze · Li, Ran · Li, Yang Yang · Hong-Ji, Wan · Yan, Jie · Wu, Kui · Cao, Fahe

ACS Applied Materials & Interfaces 2026

Specifications

Upper operating temperature

{'zh': '100', 'en': '100'} °C

Lower operating temperature

{'zh': '25', 'en': '25'} °C

Advantages

No thermal deactivation

The all-inorganic heterojunction avoids the irreversible thermal deactivation that plagues ionophore-based sensors above 50°C, operating reliably from 25 to 100°C.

Selective in high-salinity seawater

The sensor maintains high selectivity for K+ even in high-salinity seawater matrices, enabling direct deployment in marine environments.

Theory-guided design

DFT calculations predicted superior K+ selectivity over Na+ based on adsorption energetics, guiding the rational design before synthesis.

One-step synthesis

A one-step electrochemical synthesis protocol was developed to fabricate the heterostructure, simplifying production and facilitating scale-up.

Applications

• K+ monitoring in seawater：Directly detect K+ in high-salinity seawater without thermal degradation of ionophores.
• High-temperature ion detection：Operates at 100°C, enabling online K+ monitoring in high-temperature processes.
• Marine chemical sensor networks：Suitable for long-term deployment on marine buoys or underwater platforms with temperature fluctuations.
• Field analytical instruments：Integrated with open-source PTC machine learning model for real-time concentration prediction in field instruments.