A chemiresistive methane sensor.

Bezdek, Máté J; Luo, Shao-Xiong Lennon; Ku, Kang Hee; Swager, Timothy M · Proc Natl Acad Sci U S A · 2021

basic_science · Level V

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Abstract

A chemiresistive sensor is described for the detection of methane (CH<sub>4</sub>), a potent greenhouse gas that also poses an explosion hazard in air. The chemiresistor allows for the low-power, low-cost, and distributed sensing of CH<sub>4</sub> at room temperature in air with environmental implications for gas leak detection in homes, production facilities, and pipelines. Specifically, the chemiresistors are based on single-walled carbon nanotubes (SWCNTs) noncovalently functionalized with poly(4-vinylpyridine) (P4VP) that enables the incorporation of a platinum-polyoxometalate (Pt-POM) CH<sub>4</sub> oxidation precatalyst into the sensor by P4VP coordination. The resulting SWCNT-P4VP-Pt-POM composite showed ppm-level sensitivity to CH<sub>4</sub> and good stability to air as well as time, wherein the generation of a high-valent platinum intermediate during CH<sub>4</sub> oxidation is proposed as the origin of the observed chemiresistive response. The chemiresistor was found to exhibit selectivity for CH<sub>4</sub> over heavier hydrocarbons such as <i>n</i>-hexane, benzene, toluene, and <i>o</i>-xylene, as well as gases, including carbon dioxide and hydrogen. The utility of the sensor in detecting CH<sub>4</sub> using a simple handheld multimeter was also demonstrated.