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Near-Zero Power MOF-Based Sensors for NO2 Detection

Advanced Functional Materials

Small, Leo J.; Henkelis, Susan E.; Rademacher, David R.; Schindelholz, Mara E.; Krumhansl, James L.; Vogel, Dayton J.; Nenoff, T.M.

Abstract

Detection and capture of toxic nitrogen oxides (NO x ) is important for emissions control of exhaust gases and general public health. The ability to directly electrically detect trace (0.5–5 ppm) NO 2 by a metal–organic framework (MOF)‐74‐based sensor at relatively low temperatures (50 °C) is demonstrated via changes in electrical properties of M‐MOF‐74, M = Co, Mg, Ni. The magnitude of the change is ordered Ni > Co > Mg and explained by each variant's NO 2 adsorption capacity and specific chemical interaction. Ni‐MOF‐74 provides the highest sensitivity to NO 2 ; a 725× decrease in resistance at 5 ppm NO 2 and detection limit <0.5 ppm, levels relevant for industry and public health. Furthermore, the Ni‐MOF‐74‐based sensor is selective to NO 2 over N 2 , SO 2 , and air. Linking this fundamental research with future technologies, the high impedance of MOF‐74 enables applications requiring a near‐zero power sensor or dosimeter, with the active material drawing <15 pW for a macroscale device 35 mm 2 with 0.8 mg MOF‐74. This represents a 10 4 –10 6 × decrease in power consumption compared to other MOF sensors and demonstrates the potential for MOFs as active components for long‐lived, near‐zero power chemical sensors in smart industrial systems and the internet of things.

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TYPE Journal Article YEAR 2020
DOIOSTI

Tin-based ionic chaperone phases to improve low temperature molten sodium-NaSICON interfaces

Journal of Materials Chemistry A

Gross, Martha S.; Small, Leo J.; Peretti, Amanda S.; Percival, Stephen P.; Rodriguez, Mark A.; Spoerke, Erik D.

High temperature operation of molten sodium batteries impacts cost, reliability, and lifetime, and has limited the widespread adoption of these grid-scale energy storage technologies. Poor charge transfer and high interfacial resistance between molten sodium and solid-state electrolytes, however, prevents the operation of molten sodium batteries at low temperatures. Here, in situ formation of tin-based chaperone phases on solid state NaSICON ion conductor surfaces is shown in this work to greatly improve charge transfer and lower interfacial resistance in sodium symmetric cells operated at 110 °C at current densities up to an aggressive 50 mA cm-2. It is shown that static wetting testing, as measured by the contact angle of molten sodium on NaSICON, does not accurately predict battery performance due to the dynamic formation of a chaperone NaSn phase during cycling. This work demonstrates the promise of sodium intermetallic-forming coatings for the advancement of low temperature molten sodium batteries by improved mating of sodium-NaSICON surfaces and reduced interfacial resistance.

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TYPE Journal Article YEAR 2020
DOIOSTIScopus
Results 76–100 of 215
Results 76–100 of 215