Highly nanotextured β-Bi2O3 pillars by electrostatic spray deposition as photoanodes for solar water splitting

Min Woo Kim, Bhavana Joshi, Edmund Samuel, Karam Kim, Yong Il Kim, Tae Gun Kim, Mark T. Swihart, Sam S. Yoon

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

We demonstrate fabrication of films of highly textured bismuth oxide (Bi2O3) pillars via electrostatic spray deposition and test the performance of these films as photoanodes in photoelectrochemical water splitting. The β-Bi2O3 and α-Bi2O3 phases were identified and distinguished using X-ray diffraction, Raman spectroscopy, and transmission electron microscopy. The β-Bi2O3 pillars of optimized thickness exhibited a photocurrent density of 0.97 mA⋅cm−2 at 0.5 V vs Ag/AgCl. The tetragonal β-Bi2O3 pillars had enhanced visible light absorbance compared to α-Bi2O3 as well as other metal oxides like ZnO and TiO2. Tauc plot analysis of film absorbance showed a decrease in the bandgap of the β-Bi2O3 phase to 2.5 eV. In Na2SO3 electrolyte, a hole scavenger, the onset voltage for the β-Bi2O3 phase was shifted to a more negative value (−0.4 V), which increased photocurrent density. The electron concentration reached its highest value of 9.1 × 1020 cm−3 for the film with the highest photocurrent density.

Original languageEnglish
Pages (from-to)881-889
Number of pages9
JournalJournal of Alloys and Compounds
Volume764
DOIs
Publication statusPublished - 2018 Oct 5

Keywords

  • Electrostatic spray deposition
  • Mott-Schottky analysis
  • Photocurrent
  • Pillar morphology
  • Tetragonal BiO
  • Water splitting

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

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