Enhanced photocatalytic and photoelectrochemical activity in the ternary hybrid of CdS/TiO2/WO3 through the cascadal electron transfer

Hyoung Il Kim, Jungwon Kim, Wooyul Kim, Wonyong Choi

Research output: Contribution to journalArticle

200 Citations (Scopus)

Abstract

The composite of different semiconductor nanoparticles may facilitate the charge separation and transfer because the difference in the band edge positions creates the potential gradient at the composite interface. For this purpose, the CdS-TiO2-WO3 ternary hybrid was successfully synthesized and characterized for the structural, optical, and morphological properties by X-ray diffraction, diffuse reflectance UV/visible absorption spectroscopy, high-resolution transmission electron micrography, and energy-dispersive X-ray analysis. The photocatalytic activity was tested by monitoring the photoreduction of polyoxometalate (POM: PMo12O 403-) spectrophotometrically. The photoelectrochemical (PEC) property of the ternary hybrid electrode was also characterized by the linear sweep voltammetry, and the incident photon-to-current conversion efficiency was measured as a function of wavelength. The results of both the POM reduction and photocurrent tests indicated that the photocatalytic and PEC activities of the CdS-TiO2-WO3 ternary hybrid are much higher than those of bare CdS and any binary hybrids. The enhanced activity could be attributed to the cascadal electron transfer from CdS to TiO 2 to WO3 through the interfacial potential gradient in the ternary hybrid conduction bands. Such a cascadal electron transfer in the hybrid structure facilitated the charge separation and retarded the charge pair recombination. As a result, the CdS-TiO2-WO3 showed the maximum photocurrent density of 1.6 mA/cm2 (at 0 VAg/AgCl) under visible light irradiation (λ > 495 nm), which is about 5 times larger than that of bare CdS and about 2-3 times larger than that of binary composites. The enhanced electron transfer within the CdS-TiO 2-WO3 composite was also confirmed by the electrochemical impedance spectroscopy.

Original languageEnglish
Pages (from-to)9797-9805
Number of pages9
JournalJournal of Physical Chemistry C
Volume115
Issue number19
DOIs
Publication statusPublished - 2011 May 19

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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