Graphene Loading with Polypyrrole Nanoparticles for Trace-Level Detection of Ammonia at Room Temperature

Abstract

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 (NH 3 ) 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 NH 3 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.

Design and Fabrication of a Gas Sensor Based on a Polypyrrole/Silver Nanoparticle Film for the Detection of Ammonia in Exhaled Breath of COVID-19 Patients Suffering from Acute Kidney Injury

“…According to the literature, we know that PPy is very sensitive toward aminebased compounds 40,52 and NH 3. 53,54 As results show, the Au-IDEs/S-PPyMPs, as well as Au-IDEs/S-PPyMPs/AgNPs, respond to MA, DMA, TMA, EA, and TEA. Clearly, the response of Au-IDEs/S-PPyMPs/AgNPs to NH 3 is better than that of tested amine-based compounds.…”

“…Figure B indicates the dynamic response behavior of the Au-IDEs/S-PPyMPs toward NH 3 vapor. Previous works have revealed that the PPy is a p-type semiconductor with high hole mobility, showing excellent sensitivity toward amine-based compounds. ,, When the PPy surface is exposed to an amine, the amine molecules will attack the polymer backbone, decreasing the holes, which consequently results in an increase in the electrical resistance. The response of Au-IDEs/S-PPyMPs to the various concentrations of NH 3 returns to its initial resistance after exposure to air.…”

Facile Synthesis of Carbon Dot Deposited γ-FeOOH Nanosheet/Polypyrrole Composite: A Robust Photocatalyst for Degradation of Antibiotics under Sunlight Irradiation with Enhanced Antibacterial Activity

“…The C 1s spectrum of γ-FeOOH can be attributed to adventitious carbon species . In Figure a, the peak fitting analysis of C 1s for PFL/CDs-2 is deconvoluted into five components with the most predominant peak at 283.5 eV corresponding to the C sp 3 configuration (C α ) in the surface functional groups of pyrrole ring and C-dots. , In contrast, the component located at 283 eV corresponds to photoelectrons emitted from the C sp 2 configuration (C β ) of aromatic C=C bonds . The peaks corresponding to 285 eV are attributed to C–O/C–N bonds present in the pyrrole ring and C-dots surface.…”

Octahedral Molybdenum Iodide Clusters Supported on Graphene for Resistive and Optical Gas Sensing

“…Figure a shows the graphene surface once it was deposited. A highly porous surface can be noticed (BET area of 730 m 2 /g according to previous results), which can be interesting from the sensing point of view. Moreover, Figure b confirms the well-dispersed crystalline cluster particles supported on graphene.…”