Graphene Loading with Polypyrrole Nanoparticles for Trace-Level Detection of Ammonia at Room Temperature
journal contributionposted on 19.08.2021, 13:07 by Juan Casanova-Chafer, Polona Umek, Selene Acosta, Carla Bittencourt, Eduard Llobet
The outstanding versatility of graphene for surface functionalization has been exploited by its decoration with synthesized polypyrrole (PPy) nanoparticles (NPs). A green, facile, and easily scalable for mass production nanocomposite development was proposed, and the resulting PPy@Graphene was implemented in chemoresistive gas sensors able to detect trace levels of ammonia (NH3) under room-temperature conditions. Gas exposure for 5 min revealed that the presence of nanoparticles decorating graphene entail greater sensitivity (13-fold) in comparison to the bare graphene performance. Noteworthy, excellent repeatability (0.7% of relative error) and a low limit of detection of 491 ppb were obtained, together with excellent long-term stability. Besides, an extensive material characterization was conducted, and vibration bands obtained via Raman spectroscopy confirmed the formation of PPy NPs, while X-ray spectroscopy (XPS) revealed the relative abundance of the different species, as polarons and bipolarons. Additionally, XPS analyses were conducted before and after NH3 exposure to assess the PPy aging and the changes induced in their physicochemical and electronic properties. Specifically, the gas sensor was tested during a 5-month period, demonstrating significant stability over time, since just a slight decrease (11%) in the responses was registered. In summary, the present work reports for the first time the use of PPy NPs decorating graphene for gas-sensing purposes, revealing promising properties for the development of unattended gas-sensing networks for monitoring air quality.
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stabilityPPy NPsX-ray spectroscopygraphene performance5 mingas sensorTrace-Level Detectionvibration bandstrace levelsmonitoring air qualitynanoparticles decorating grapheneRaman spectroscopygas exposureXPS analysesNH 3work reportsroom-temperature conditionsgas-sensing purposesPolypyrrole Nanoparticles5- month period491 ppbmass production nanocomposite devel...NH 3 exposuregas-sensing networksGraphene Loadingsurface functionalizationmaterial characterizationchemoresistive gas sensorsRoom TemperaturePPy NPs decorating graphene