Dispersible composites of exfoliated graphite and polyaniline with improved electrochemical behaviour for solid-state chemical sensor applicationsстатья
Статья опубликована в высокорейтинговом журнале
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Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 10 ноября 2014 г.
Аннотация:We report here the in situ polymerization of aniline in the presence of exfoliated graphite of two different
grades (graphene and graphite) resulting in composite materials which are readily dispersible in N-methylpyrrolidone. Compared to polyaniline (PANI) prepared without graphene/graphite which becomes
electrically non-conducting at pH > 3, the PANI–graphene/graphite composites showed significantly
improved pH stability and electrochemical behaviour in aqueous electrolyte solutions at pH = 8, without
any further need of surface functionalization of the graphene/graphite flakes to stabilize the conducting
form of polyaniline (PANI). The improved electroactivity is ascribed to the synergistic effect of graphene/
graphite and PANI, and the network formation of the electrically conducting exfoliated graphites in the
PANI matrix, which was electrochemically confirmed by simple cyclic voltammetric measurements at pH
= 9.5 in the presence of the Ru(NH3)6^2+/3+ and Fe(CN)6^3+/4+ redox couples. Due to the dispersibility of
the composites, thin films possessing stability in water can easily be prepared by solution casting for
different types of solid-state chemical sensor and ion-selective electrode applications operating at
neutral pH. By using sodium ascorbate as a model substance, we show that its amperometric detection
at pH = 7.3 with the PANI–graphite films results in a current amplification of 1.3–10.2 times in the
concentration range of 10^-4–10^-2 M, compared to conventional PANI, which clearly demonstrates the
advantage of incorporating exfoliated graphites in the PANI films. The materials reported in this paper
were systematically characterized with cyclic voltammetry, FTIR, Raman and X-ray photoelectron
spectroscopy, scanning electron microscopy, X-ray diffraction and electrical conductivity measurements.