Facet effect on the photoelectrochemical performance of a WO3/BiVO4 heterojunction photoanode

Yang Liu, Bryan R. Wygant, Kenta Kawashima, Oluwaniyi Mabayoje, Tae Eun Hong, Sang Geul Lee, Jie Lin, Jun Hyuk Kim, Kunio Yubuta, Wenzhang Li, Jie Li, C. Buddie Mullins

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

Different WO3 facets have different surface energies and electronic structures, and exhibit different water oxidation abilities and photocatalytic performance as a result. Because of the material's limited photoresponse region, loading a narrow bandgap material on WO3 is a generally known method for improving photo-harvesting. In this paper, we have synthesized WO3 films with different crystal facet ratios. After loading BiVO4 on these WO3 films, we measured the photoelectrochemical (PEC) performance to investigate the effects of WO3 facet choice on the heterojunction film electrode's performance. We found that a high-intensity ratio of the (002) WO3 facet in X-ray diffraction (XRD) leads to a more negative onset potential and higher photocurrents in a lower potential region. The ultraviolet photoelectron spectra show a lower work function for the 002-dominant WO3 film compared to other WO3 films, which may result in a higher quasi-fermi level for the heterojunction electrode. Based on the XRD results, the high-intensity ratio of the (002) WO3 facet preferentially exposes the (020) BiVO4 facet, which may be a reason for the better charge extraction observed at low applied potential and high faradic efficiency on PEC water splitting. Together, this results in a high hole injection efficiency for 002-dominant WO3/BiVO4 films compared with WO3/BiVO4 films favoring other WO3 facet ratios.

Original languageEnglish
Pages (from-to)227-239
Number of pages13
JournalApplied Catalysis B: Environmental
Volume245
DOIs
Publication statusPublished - 2019 May 15

Keywords

  • BiVO
  • Facet effect
  • Heterojunction
  • Photoelectrochemical performance
  • WO

ASJC Scopus subject areas

  • Catalysis
  • Environmental Science(all)
  • Process Chemistry and Technology

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    Liu, Y., Wygant, B. R., Kawashima, K., Mabayoje, O., Hong, T. E., Lee, S. G., Lin, J., Kim, J. H., Yubuta, K., Li, W., Li, J., & Mullins, C. B. (2019). Facet effect on the photoelectrochemical performance of a WO3/BiVO4 heterojunction photoanode. Applied Catalysis B: Environmental, 245, 227-239. https://doi.org/10.1016/j.apcatb.2018.12.058