Available online 31 May 2008.
Nano-structured TiO2/carbon clusters/Cr2O3 composite material has been successfully obtained by the microwave treatment of a TiO(acac)/Cr(acac)3/epoxy resin complex. The compositions of the composite materials were determined using ICP, elemental analysis and surface characterization by SEM–EDX, TEM and XRD. ESR spectral examinations suggest the possibility of an electron transfer in the process of TiO2 → carbon clusters → Cr2O3 with an oxidation site at TiO2 particles and a reduction site at Cr2O3 particles. The preliminary experimental results show that the calcined materials could decompose methylene blue under visible-light irradiation.
Keywords: Nano-structures; Polymers; Carbon clusters; Titanium dioxide; Electron transfer
PACS classification codes: 71.20.Rv; 71.20.Nr; 72.80.Tm; 73.63.Bd; 74.25.Jb
Fig. 1. SEM–EDX spectra of complex III.
Fig. 2. XRD patterns of calcined materials: (a) Ic's, (b) IIc's and (c) IIIc's.
Fig. 3. TEM images of calcined materials: (a) Ic's, (b) IIc's and (c) IIIc's.
Fig. 4. ESR spectra of calcined material Ic-4 in the presence of 1,4-benzoquinone and 1,4-hydroquinone.
Fig. 5. ESR spectra of calcined material IIc-4 in the presence of 1,4-benzoquinone and 1,4-hydroquinone.
Fig. 6. UV–vis spectra of methylene blue in the presence of IIIc-5.
Fig. 7. Relationship between the amounts of decomposed methylene blue and the reaction time in the presence of Ic-6, IIc-6 and IIIc-6 under the visible-light irradiation and/or in the dark.
Scheme 1. Synthesis of complexes and calcined materials.
Scheme 2. Schematic energy level diagram for TiO2, carbon clusters and Cr2O3 and plausible electron transfer process in the composite materials (V.B. is valence band, C.B. is conduction band and Eg is band gap energy).
Charged amounts of reagents
Elemental analyses of complexes and calcined materials