Catalysis

Engineering

Fabrication

Materials science

Chromatography

Layer (electronics)

Ammonia

Humidity

Chemical engineering

Physical chemistry

Alternative medicine

Capacitive sensing

Thermodynamics

Physics

Nanotechnology

Organic chemistry

Thin film

Analytical Chemistry (journal)

Medicine

Chemistry

Selectivity

Electrode

Detection limit

Optoelectronics

Electrical engineering

Pathology

ACS Sensors

This work reports on the fabrication and deployment of a select metal-organic framework (MOF) thin film as an advanced chemical capacitive sensor for the sensing/detection of ammonia (NH3) at room temperature. Namely, the MOF thin film sensing layer consists of a rare-earth (RE) MOF (RE-fcu-MOF) deposited on a capacitive interdigitated electrode (IDE). Purposely, the chemically stable naphthalene-based RE-fcu-MOF (NDC-Y-fcu-MOF) was elected and prepared/arranged as a thin film on a prefunctionalized capacitive IDE via the solvothermal growth method. Unlike earlier realizations, the fabricated MOF-based sensor showed a notable detection sensitivity for NH3 at concentrations down to 1 ppm, with a detection limit appraised to be around 100 ppb (at room temperature) even in the presence of humidity and/or CO2. Distinctly, the NDC-Y-fcu-MOF based sensor exhibited the required stability to NH3, in contrast to other reported MOFs, and a remarkable detection selectivity toward NH3 vs CH4, NO2, H2, and C7H8. The NDC-Y-fcu-MOF based sensor exhibited excellent performance for sensing ammonia for simulated breathing system in the presence of the mixture of carbon dioxide and/or humidity (water vapor), with no major alteration in the detection signal.

MOFs for the Sensitive Detection of Ammonia: Deployment of fcu-MOF Thin Films as Effective Chemical Capacitive Sensors