Low Temperature Synthesis of TiO2-β-Cyclodextrin-Graphene Nanocomposite for Energy Storage and Photocatalytic Applications

Vittal Sharavath, Suprabhat Sarkar, Dayakar Gandla, Sutapa Ghosh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

In this work, TiO2-β-cyclodextrin-graphene nanocomposite (TiO2-CD@GNS) has been synthesized by a simple water phase approach at 90 °C. We have used functional properties of β-cyclodextrin to stabilize graphene in aqueous medium which can facilitate the self assembly of in situ grown anatase TiO2 nanoparticles (TiO2 NPs) on graphene nanosheets (GNS). This nanocomposite is found to exhibit better energy storage capacity and photocatalytic activity than TiO2-reduced graphene oxide (TiO2-RGO) composites. 100% photodegradation of methylene blue is observed within 25 min under visible light using TiO2-CD@GNS which clearly explains its high photocatalytic activity. This may be due to increased visible light absorption and electron transfer via Ti-O-C between Ti and C which greatly retards the effective recombination of photogenerated electron-hole pairs. For energy storage applications, this material showed its capability of delivering 266.6 Fg-1 capacitance at a scan rate of 1 mVs-1 from cyclic voltammetry and excellent cyclic stability with 90% capacitance retention after 1000 continuous charge/discharge cycles at 1 Ag-1 current density. The capacitance of the TiO2-CD@GNS electrode was 20% higher than TiO2-RGO electrode (222.9 Fg-1 at 1 mVs-1) and 2 times higher than CD@GNS electrode (115.4 Fg-1 at 1 mVs-1). This enhanced capacitance was attributed to the charge transfer between electrode-electrolyte interfaces and hydrophilic nature of the composite which enhances wettability of aqueous electrolytes. This may be due to functionalization of graphene and uniform dispersion of small sized (<10 nm) TiO2 NPs onto CD@GNS surface without agglomeration which brings about supramolecular host-guest interactions. Here, the CD moiety loaded on graphene nanosheets acted as linkers between them and works as stabilizing agent for the TiO2 NPs to prevent agglomeration.

Original languageEnglish
Pages (from-to)385-394
Number of pages10
JournalElectrochimica Acta
Volume210
DOIs
StatePublished - 20 Aug 2016
Externally publishedYes

Keywords

  • Graphene
  • Photocatalysis
  • Supercapacitor
  • Titanium dioxide
  • β-Cyclodextrin

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