Polypyrrole Nanotubes and Their Carbonized Analogs: Synthesis, Characterization, Gas Sensing Properties

Abstract

Polypyrrole (PPy) in globular form and as nanotubes were prepared by the oxidation of pyrrole with iron(III) chloride in the absence and presence of methyl orange, respectively. They were subsequently converted to nitrogen-containing carbons at 650 °C in an inert atmosphere. The course of carbonization was followed by thermogravimetric analysis and the accompanying changes in molecular structure by Fourier Transform Infrared and Raman spectroscopies. Both the original and carbonized materials have been tested in sensing of polar and non-polar organic vapors. The resistivity of sensing element using globular PPy was too high and only nanotubular PPy could be used. The sensitivity of the PPy nanotubes to ethanol vapors was nearly on the same level as that of their carbonized analogs (i.e., ~18% and 24%, respectively). Surprisingly, there was a high sensitivity of PPy nanotubes to the n-heptane vapors (~110%), while that of their carbonized analog remained at ~20%. The recovery process was significantly faster for carbonized PPy nanotubes (in order of seconds) compared with 10 s of seconds for original nanotubes, respectively, due to higher specific surface area after carbonization.

Conversion of conducting polypyrrole nanostructures to nitrogen-containing carbons and its impact on the adsorption of organic dye

“…The specific surface area of globular polypyrrole increased from 75 m 2 g −1 to 211 m 2 g −1 after being exposed to 650°C in inert atmosphere. 12 The carbonization and activation at the same temperature produced the carbons with the specific surface area exceeding 1000 m 2 g −1 . [13][14][15] The reported results are confronted with those obtained in the present study.…”

“…Polypyrrole nanotubes are of special interest due to their uniform morphology. 10 They convert similarly to nitrogen-containing carbon nanotubes 12,[16][17][18][19][20] and can be applied as new nanostructured nitrogen-enriched carbons. The carbonization of polypyrrole nanotubes improved the specific surface area from 86 m 2 g −1 to 105 m 2 g −1 .…”

Polypyrrole Nanopipes as a Promising Cathode Material for Li‐ion Batteries and Li‐ion Capacitors: Two‐in‐One Approach

“…As shown in Figure , PPy‐NPipes were prepared via a chemical oxidation mediated soft template‐directed route using anions azo dye methyl orange (MO). The detailed growth mechanism of PPy‐NPipes is explained elsewhere . Further, N‐CNpipes were obtained via carbonization of PPy‐NPipes at 800 °C for 1 h with a heating rate of 5 °C min −1 under N 2 atmosphere (see Figure S1 for TGA analysis).…”

“…The detailed growth mechanism of PPy-NPipes is explained elsewhere. [21][22][23] Further, N-CNpipes were obtained via carbonization of PPy-NPipes at 800°C for 1 h with a heating rate of 5°C min À 1 under N 2 atmosphere (see Figure S1 for TGA analysis).…”

Antibody Biomimetic Material Made of Pyrrole for CA 15-3 and Its Application as Sensing Material in Ion-Selective Electrodes for Potentiometric Detection

“…In turn, the physical arrangement of the polymer nanostructures depended on the electrical conditions related to the electropolymerization. Considering previous studies on a stainless steel surface, the nanostructural arrangement of PPy could vary from nanobelts, to nanobricks or nanosheets, depending of the scan-rate of the CV [ 29 , 34 ]. For high scanning speeds (200 mV/s) the time allowed for deposition and dissolution of the polymeric network decreased, yielding a porous structure with a low level of crystallization, organized in multiple layers of nanosheets.…”