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Updated: Jun 13, 2026
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Surface Functionalization of Metal-Organic Frameworks for Improved Moisture Resistance
Published on: September 5, 2018
Transferable Two-Dimensional Hydrophobic Metal-Organic Framework Encapsulation of MoS2-Based Humidity-Resistant NO2
Lei Zhao1,2, Junwei Zeng3, Yiquan Xiong2,4
1Department of Physics and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology, Shenzhen 518055, P. R. China.
ACS Sensors
|June 11, 2026
Summary
A new hydrophobic encapsulation strategy using a metal-organic framework (MOF) protects molybdenum disulfide (MoS2) gas sensors from humidity. This method significantly improves nitrogen dioxide (NO2) detection accuracy and stability in humid environments.
Area of Science:
- Materials Science
- Nanotechnology
- Chemical Engineering
Background:
- Humidity negatively impacts gas sensor performance, particularly for large surface area two-dimensional (2D) materials like molybdenum disulfide (MoS2).
- Water molecule adsorption on sensor surfaces leads to decreased detection accuracy and reliability.
- Developing strategies to mitigate humidity effects is crucial for practical gas sensing applications.
Purpose of the Study:
- To propose and demonstrate a hydrophobic encapsulation strategy for MoS2 gas sensors.
- To suppress water adsorption on MoS2 using a porous metal-organic framework (MOF).
- To enhance the humidity resistance and detection performance of MoS2-based gas sensors.
Main Methods:
- Synthesized porous poly[Fe(benzimidazole)2] (Fe_n(bim)_2n) MOF flakes via ammonia-assisted chemical vapor deposition on mica.
- Transferred Fe_n(bim)_2n flakes onto MoS2 using a polydimethylsiloxane (PDMS) assisted method, creating a hydrophobic encapsulation layer.
- Fabricated and tested Fe_n(bim)_2n/MoS2 heterojunction gas sensors for NO2 detection under varying humidity levels.
Main Results:
- The Fe_n(bim)_2n/MoS2 heterojunction exhibited highly humidity-resistant NO2 sensing, with only a 4.28% response variation between 40-70% relative humidity (RH).
- The sensor showed a significant increase in NO2 response (from 0.53 to 2.03) at 70% RH compared to bare MoS2.
- A low practical limit of detection (LOD) of 20 ppb for NO2 was achieved, even at high humidity.
Conclusions:
- The hydrophobic Fe_n(bim)_2n encapsulation effectively suppresses water adsorption on MoS2, mitigating humidity-induced performance fluctuations.
- The charge transfer within the Fe_n(bim)_2n/MoS2 heterojunction further contributes to improved sensing performance.
- This encapsulation strategy offers a promising approach for developing robust and reliable gas sensors for practical applications.
Keywords:
2D metal−organic frameworkchemical vapor depositiongas sensorhumidity resistancehydrophobic encapsulationroom temperature
