期刊
ACS OMEGA
卷 5, 期 1, 页码 643-649出版社
AMER CHEMICAL SOC
DOI: 10.1021/acsomega.9b03246
关键词
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资金
- Ontario Centres of Excellence (OCE) Talent Edge Postdoctoral Fellowship
- Canada Foundation for Innovation [212442]
- Discovery Grant program of the Natural Sciences and Engineering Research Council of Canada [RGPIN-2015-06004]
Sensing of metal contaminants at ultralow concentrations in aqueous environments is vital in today's overpopulated world, with an extremely stringent limit (<5 ppb) for Cd2+ ions in drinking water. Here, we utilize sonochemically exfoliated molybdenum disulfide (MoS2) nanosheets functionalized with L-cysteine (Cys) as highly sensitive and selective two-dimensional (2D) materials for solid-state chemiresistors. We specifically targeted Cd2+ ions due to their high toxicity at low concentrations. MoS2-Cys nanosheets are fabricated using an ad hoc, low-complexity, one-pot synthesis method. Porous MoS2-Cys thin films with a high surface area are assembled from these nanosheets. Two-terminal chemiresistors incorporating MoS2- Cys films are deinonstrated to be preferentially sensitive to Cd2+ ions at neutral pH, irrespective of other metal ions present in water flowing through the device. A 5 ppb concentration of the Cd2+ ions in the water stream increases the device resistivity by 20 times. Our devices operate at broad (1-500 ppb) range and fast (similar to 1 s) response times. Cd2+ is selectively detected because of preferential, size-driven adsorption at the interstitials between L-cysteine functional groups, combined with pH-controlled charge transfer that removes electronic gap states from MoS2. MoS2-Cys-based chemiresistors can be deployed in-line to detect metal ions without any need for additional offline measurements.
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