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Detection of volatile organic compounds by weight-detectable sensors coated with metal-organic frameworks.

Yamagiwa H, Sato S, Fukawa T, Ikehara T, Maeda R, Mihara T, Kimura M - Sci Rep (2014)

Bottom Line: Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper.The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors.Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan.

ABSTRACT
Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper. The thin films of two MOFs were grown from COOH-terminated self-assembled monolayers onto the gold electrodes of sensor platforms. The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors. Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

No MeSH data available.


Related in: MedlinePlus

a) Vapor response isotherms of QCM sensors modified with Cu3(BTC)2 to ethanol (), acetone (), toluene (), and n-octane () at 60°C. b) Vapor response isotherms to n-hexane (), n-haxanol (), n-heptane (), n-heptanol (), n-octane (), and n-octanol () at 60°C. (c) Vapor response isotherms to o-xylene (), m-xylene (), and p-xylene () at 60°C.
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f3: a) Vapor response isotherms of QCM sensors modified with Cu3(BTC)2 to ethanol (), acetone (), toluene (), and n-octane () at 60°C. b) Vapor response isotherms to n-hexane (), n-haxanol (), n-heptane (), n-heptanol (), n-octane (), and n-octanol () at 60°C. (c) Vapor response isotherms to o-xylene (), m-xylene (), and p-xylene () at 60°C.

Mentions: Figure 3a shows the adsorption isotherms of QCMs coated with Cu3(BTC)2 for four VOCs recorded at 60°C. The Cu3(BTC)2-coated QCM isotherms for four VOCs showed a Langmuir-type sorption within this concentration range, and the response sequence was ethanol > acetone > toluene > n-octane. The selectivity of the VOC sensing is caused by the following two factors, the chemical interactions of the VOCs with the MOF internal surface and the molecular sieving effect of the regulated nanospace within the three-dimensional MOF frameworks. Since the internal surface of Cu3(BTC)2 is hydrophilic due to the presence of two water molecules coordinated at the axial positions of the Cu2+-paddlewheels, the hydrophilic surface can interact with any polar VOC vapors such as ethanol and acetone. The regulated pore and aperture sizes in the crystalline MOFs would allow for the size selectivity of the adsorption process of the VOCs. Figure 3b shows the adsorption isotherms of Cu3(BTC)2-coated QCMs for alkanes and alkyl alcohols possessing different alkyl chain lengths. The isotherm of n-hexanol was almost consistent with that of n-hexane, and the response sequence followed the molecular size of the VOCs. Furthermore, the sensors displayed different isotherms for o-xylene, m-xylene, and p-xylene, implying the recognition of positional isomers of xylene compounds by the Cu3(BTC)2 layer (Figure 3c). Thus, the Cu3(BTC)2 layer provides for the selectivity of VOC sensing to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.


Detection of volatile organic compounds by weight-detectable sensors coated with metal-organic frameworks.

Yamagiwa H, Sato S, Fukawa T, Ikehara T, Maeda R, Mihara T, Kimura M - Sci Rep (2014)

a) Vapor response isotherms of QCM sensors modified with Cu3(BTC)2 to ethanol (), acetone (), toluene (), and n-octane () at 60°C. b) Vapor response isotherms to n-hexane (), n-haxanol (), n-heptane (), n-heptanol (), n-octane (), and n-octanol () at 60°C. (c) Vapor response isotherms to o-xylene (), m-xylene (), and p-xylene () at 60°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4150105&req=5

f3: a) Vapor response isotherms of QCM sensors modified with Cu3(BTC)2 to ethanol (), acetone (), toluene (), and n-octane () at 60°C. b) Vapor response isotherms to n-hexane (), n-haxanol (), n-heptane (), n-heptanol (), n-octane (), and n-octanol () at 60°C. (c) Vapor response isotherms to o-xylene (), m-xylene (), and p-xylene () at 60°C.
Mentions: Figure 3a shows the adsorption isotherms of QCMs coated with Cu3(BTC)2 for four VOCs recorded at 60°C. The Cu3(BTC)2-coated QCM isotherms for four VOCs showed a Langmuir-type sorption within this concentration range, and the response sequence was ethanol > acetone > toluene > n-octane. The selectivity of the VOC sensing is caused by the following two factors, the chemical interactions of the VOCs with the MOF internal surface and the molecular sieving effect of the regulated nanospace within the three-dimensional MOF frameworks. Since the internal surface of Cu3(BTC)2 is hydrophilic due to the presence of two water molecules coordinated at the axial positions of the Cu2+-paddlewheels, the hydrophilic surface can interact with any polar VOC vapors such as ethanol and acetone. The regulated pore and aperture sizes in the crystalline MOFs would allow for the size selectivity of the adsorption process of the VOCs. Figure 3b shows the adsorption isotherms of Cu3(BTC)2-coated QCMs for alkanes and alkyl alcohols possessing different alkyl chain lengths. The isotherm of n-hexanol was almost consistent with that of n-hexane, and the response sequence followed the molecular size of the VOCs. Furthermore, the sensors displayed different isotherms for o-xylene, m-xylene, and p-xylene, implying the recognition of positional isomers of xylene compounds by the Cu3(BTC)2 layer (Figure 3c). Thus, the Cu3(BTC)2 layer provides for the selectivity of VOC sensing to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

Bottom Line: Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper.The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors.Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Textile Science and Technology, Shinshu University, Ueda 386-8567, Japan.

ABSTRACT
Detection of volatile organic compounds (VOCs) using weight-detectable quartz microbalance and silicon-based microcantilever sensors coated with crystalline metal-organic framework (MOF) thin films is described in this paper. The thin films of two MOFs were grown from COOH-terminated self-assembled monolayers onto the gold electrodes of sensor platforms. The MOF layers worked as the effective concentrators of VOC gases, and the adsorption/desorption processes of the VOCs could be monitored by the frequency changes of weight-detectable sensors. Moreover, the MOF layers provided VOC sensing selectivity to the weight-detectable sensors through the size-selective adsorption of the VOCs within the regulated nanospace of the MOFs.

No MeSH data available.


Related in: MedlinePlus