Interfacial Redox-Driven Crystallization on MXene Enables Ultrasensitive Hg²⁺ Detection.

Area of Science:

• Nanophotonics
• Environmental Science
• Materials Science

Background:

• Mercury contamination is a significant environmental and public health concern.
• Rapid and ultrasensitive detection methods for trace mercury levels are crucial.

Purpose of the Study:

• To develop a novel sensing platform for ultrasensitive detection of mercury ions (Hg²⁺).
• To integrate MXene materials with fiber-optic interferometers for enhanced sensing capabilities.

Main Methods:

• Synthesis of mono- and bilayer Ti₃C₂T_x MXene nanosheets using a layer delamination method.
• Fabrication of an MXene-integrated fiber-optic Fabry-Pérot interferometer (MXene-FFPI).
• Utilizing interfacial redox-driven crystallization for mercury detection and signal transduction.

Main Results:

• The MXene-FFPI demonstrated ultrahigh sensitivity (5 pm/nM) for Hg²⁺ detection.
• Achieved a trace-level limit of detection (LOD) of 0.2 nM (0.04 ppb), significantly below WHO guidelines.
• MXene acted as an efficient optical transducer and signal amplifier, converting chemical capture into optical signals.

Conclusions:

• The developed MXene-FFPI provides a promising nanophotonic architecture for ultrasensitive environmental monitoring.
• This technology enables the conversion of interfacial reactions into amplified optical signals.
• The platform holds potential for advanced biomedical sensing applications.