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Title: Preparation, characterization and gas sensitivity of polypyrrole/γ-Fe{sub 2}O{sub 3} hybrid materials

Graphical abstract: - Highlights: • PPy/γ-Fe{sub 2}O{sub 3} hybrid materials were prepared by sol–gel polymerization in situ. • Different reactant molar ratios resulted in different microstructures of γ-Fe{sub 2}O{sub 3} and molecular weights of PPy. • PPy/γ-Fe{sub 2}O{sub 3} hybrids had selectivity for NH{sub 3} gases at low temperatures (<100 °C). • The sensing mechanism was suggested to be related to the existence of p–n heterojunctions in the PPy/γ-Fe{sub 2}O{sub 3} hybrid material. - Abstract: Polypyrrole (PPy)/γ-Fe{sub 2}O{sub 3} hybrid materials were prepared by sol–gel polymerization in situ and characterized by Fourier transform infrared (FT-IR), X-ray powder diffraction (XRD), thermogravimetric and differential thermal analysis (TG–DTA) and high-resolution transmission electron microscope (HRTEM). The gas sensitivities in CO, H{sub 2}, NH{sub 3}, ethanol or acetone atmospheres were determined at 30 °C, 60 °C and 90 °C. FT-IR and XRD patterns suggest that ferric oxide in the hybrids was γ-Fe{sub 2}O{sub 3}, with a diameter of approximately 5 nm. TG–DTA and HRTEM analyses showed that different reactant molar ratios of pyrrole monomer: Fe(NO{sub 3}){sub 3}·9H{sub 2}O resulted in different microstructures of γ-Fe{sub 2}O{sub 3} and molecular weights of PPy. An increased amount of Fe(NO{sub 3}){sub 3}·9H{sub 2}O increased the degree of uniformity ofmore » the molecular weight of PPy and resulted in a change of γ-Fe{sub 2}O{sub 3} microstructure from granular to stick particles. The results of gas sensitivities showed that the PPy/γ-Fe{sub 2}O{sub 3} hybrids exhibited high sensitivity to NH{sub 3} at mild operating temperature (<100 °C). Furthermore, the sensing mechanism was also discussed.« less
Authors:
 [1] ;  [2]
  1. Department of Chemistry, Hebei Normal University, Shijiazhuang 050016 (China)
  2. Department of Chemistry, Nankai University, Tianjin 300071 (China)
Publication Date:
OSTI Identifier:
22285165
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 48; Journal Issue: 10; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AMMONIA; ATMOSPHERES; CALORIMETRY; CARBON MONOXIDE; FERRITES; HETEROJUNCTIONS; HYBRIDIZATION; INFRARED SPECTRA; IRON OXIDES; MICROSTRUCTURE; MOLECULAR WEIGHT; POLYMERIZATION; THERMAL GRAVIMETRIC ANALYSIS; TRANSMISSION ELECTRON MICROSCOPY; X-RAY DIFFRACTION