Dual-Modulated Heterojunctions for Anti-Interference Sensing of Heavy Metals in Seawater

Area of Science:

• Electrochemistry
• Materials Science
• Environmental Sensing

Background:

• Classic redox-based electrochemical sensors struggle with matrix effects in complex environments like seawater.
• High salinity and interfering species in seawater lead to false signals, reducing sensor sensitivity and specificity.
• Detecting trace analytes in challenging matrices requires novel sensing strategies beyond traditional redox mechanisms.

Purpose of the Study:

• To develop a novel electrochemical sensing mode for trace analyte detection in complex matrices.
• To overcome the limitations of redox-based sensors by utilizing dual-modulated interfacial energy barriers.
• To create a robust and highly sensitive sensor for Cu2+ detection in seawater.

Main Methods:

• Constructed a hierarchical structure of Ni/TiO2/porous-reduced graphene oxide/chitosan (CS) to form Schottky junctions.
• Employed a dual-modulation strategy involving light and electrostatic interactions to regulate interfacial energy barriers.
• Investigated the sensor's response to Cu2+ and its robustness against interfering species in a simulated seawater matrix.

Main Results:

• The dual-modulated sensing mode exponentially magnified sensing signals in response to Cu2+.
• The proposed sensor demonstrated robustness against interfering species due to inert electrostatic interactions.
• Illumination enhanced sensitivity by 6.23 times, achieving a limit of detection of 0.22 nM for Cu2+.
• The sensing mode was validated in other heterojunctions (Ni/NiO/MoS2/CS), showing potential for universal applications.

Conclusions:

• The novel dual-modulated interfacial energy barrier approach offers a robust and highly sensitive method for trace analyte detection in complex environments.
• This strategy effectively overcomes the limitations of conventional redox-based sensors, particularly in saline matrices.
• The developed sensor technology holds significant promise for environmental monitoring and other universal electrochemical sensing applications.