H⁺ Exchange-Driven ppb-Level and High-Selective Formaldehyde Detection at Room Temperature for Environmental and...

Area of Science:

• Materials Science
• Chemical Sensing
• Nanotechnology

Background:

• Formaldehyde is a common air pollutant and a biomarker for diseases.
• Detecting formaldehyde at low concentrations is challenging due to interference from other volatile organic compounds (VOCs).

Purpose of the Study:

• To enhance the sensing performance of sodium titanate (Na2Ti3O7, NTO) for formaldehyde detection.
• To develop a selective and sensitive formaldehyde sensor for air quality monitoring and disease screening.

Main Methods:

• Utilizing an H⁺-exchange strategy to modify NTO, creating H⁺-exchanged NTO (H-NTO).
• Introducing surface hydroxyl groups and tuning conduction pathways in H-NTO for selective formaldehyde adsorption.
• Developing a handheld H-NTO prototype integrated with machine learning for practical applications.

Main Results:

• H-NTO demonstrated an ultralow detection limit of 2 ppb for formaldehyde.
• The sensor exhibited a wide dynamic range (up to 100 ppm) and eliminated cross-sensitivity to other VOCs.
• The H-NTO prototype achieved high diagnostic accuracy for non-invasive breast cancer screening using breath analysis.

Conclusions:

• H⁺-exchange is an effective strategy for significantly improving formaldehyde sensor performance.
• The developed H-NTO sensor shows great potential for both environmental monitoring and early disease detection.