Synthesis and characterisation of a novel bilayer tungsten trioxide nanojunction with different crystal growth orientation for improved photoactivity under visible light irradiation

Tao Zhu, Meng Nan Chong, Eng Seng Chan, Joey D. Ocon

Research output: Contribution to journalArticleResearchpeer-review

7 Citations (Scopus)

Abstract

The main aim of this study was to prove the concept and elucidate the effect of a bilayer tungsten trioxide (WO3) nanojunction with different crystal growth orientation for improved photoactivity under visible light irradiation. For the first time, the concept of a bilayer WO3 nanojunction with different crystal growth orientation was demonstrated. A layer-by-layer assembly for the bilayer WO3 nanojunction with the same monoclinic ɣ-WO3 crystal structure, but with two different crystal growth orientation of {002} at 600 °C and {200} at 500 °C was synthesized via the controlled electrodeposition-annealing method. Photocurrent measurements showed that the individual photoactivity of WO3 thin film with {002} crystal growth orientation was higher than that of WO3 thin film with {200} crystal growth orientation, while the bilayer WO3 nanojunction with different crystal growth orientation exhibited the highest photoactivity. To further characterise the bilayer WO3 nanojunction, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), high resolution-transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and photocurrent density measurements were performed. Based on the findings, a theoretical postulation model was proposed in explaining the transfer of photogenerated charge carriers in bilayer WO3 nanojunction that leads to improved photoactivity under visible light irradiation.

Original languageEnglish
Pages (from-to)268-275
Number of pages8
JournalJournal of Alloys and Compounds
Volume749
DOIs
Publication statusPublished - 15 Jun 2018

Keywords

  • Cathodic electrodeposition
  • Photoelectrocatalyst
  • Photoelectrochemical water splitting
  • Solar fuel
  • Water oxidation

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