Morphology-controllable synthesis and characterization of carbon nanotube/polypyrrole composites and their hydrogen storage capacities

Burcu Saner Okan*, Jamal Seyyed Monfared Zanjani, Ilse Letofsky-Papst, Fevzi Çakmak Cebeci, Yusuf Z. Menceloglu

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Scopus)

Abstract

Sphere-like and layer-by-layer growth mechanisms of polypyrrole are controlled by changing pyrrole monomer concentration and using carbon nanotubes (CNT) as template. Pristine polypyrrole has sphere-like structures but remarkable change in types of polypyrrole growth is observed from spherical-like to layer-by-layer structures in the presence of CNT. Acid treatment enhances polypyrrole coverage on CNT surface by preventing agglomeration of polypyrrole due to an increase in surface oxygen groups and sp2 bonds in CNT structure. The crystallinity of powders comparably decreases after polypyrrole coating due to the amorphous structure of polypyrrole and a sharp decrease in the intensity of 002 peak. The influence of surface functionalization and polymer coating on the structural parameters of multi-walled CNT and their composites is investigated by tailoring the feeding ratio of polypyrrole. The hydrogen sorption measurements at ambient conditions by Intelligent Gravimetric Analyzer demonstrate that hydrogen uptake of CNT/polypyrrole composite is 1.66 wt.% which is almost 3 times higher than that of pristine CNT. Higher hydrogen uptake values are obtained by keeping the mass ratio of pyrrole monomer and CNT equal by using non-functionalized CNT in composite production. Hydrogen adsorption/desorption kinetics of polypyrrole/CNT composites is improved by increasing adsorption sites after polymer coating and acid treatment. The desorption curves of these modified surfaces are higher than their adsorption curves at lower pressures and hysteresis loop is observed in their isotherms since hydrogen is chemically bonded to the modified surfaces by the conversion of carbon atoms from sp2 to sp3 hybridization.

Original languageEnglish
Pages (from-to)171-180
Number of pages10
JournalMaterials chemistry and physics
Volume167
DOIs
Publication statusPublished - 1 Nov 2015
Externally publishedYes

Keywords

  • Adsorption
  • Composite materials
  • Desorption
  • Oxidation
  • Polymers
  • Surface properties

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