Integration of Molybdenum-Doped, Hydrogen-Annealed BiVO 4 with Silicon Microwires for Photoelectrochemical Applications

Alexander Milbrat, Wouter Vijselaar, Yuxi Guo, Bastian Mei, Jurriaan Huskens*, Guido Mul*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)
20 Downloads (Pure)

Abstract

H-BiVO 4-x :Mo was successfully deposited on microwire-structured silicon substrates, using indium tin oxide (ITO) as an interlayer and BiOI prepared by electrodeposition as precursor. Electrodeposition of BiOI, induced by the electrochemical reduction of p-benzoquinone, appeared to proceed through three stages, being nucleation of particles at the base and bottom of the microwire arrays, followed by rapid (homogeneous) growth, and termination by increasing interfacial resistances. Variations in charge density and morphology as a function of spacing of the microwires are explained by (a) variations in mass transfer limitations, most likely associated with the electrochemical reduction of p-benzoquinone, and (b) inhomogeneity in ITO deposition. Unexpectedly, H-BiVO 4-x :Mo on microwire substrates (4 μm radius, 4 to 20 μm spacing, and 5 to 16 μm length) underperformed compared to H-BiVO 4-x :Mo on flat surfaces in photocatalytic tests employing sulfite (SO 3 2- ) oxidation in a KPi buffer solution at pH 7.0. While we cannot exclude optical effects, or differences in material properties on the nanoscale, we predominantly attribute this to detrimental diffusion limitations of the redox species within the internal volume of the microwire arrays, in agreement with existing literature and the observations regarding the electrodeposition of BiOI. Our results may assist in developing high-efficiency PEC devices.

Original languageEnglish
Pages (from-to)5034-5044
Number of pages11
JournalACS Sustainable Chemistry and Engineering
Volume7
Issue number5
DOIs
Publication statusPublished - 4 Mar 2019

Keywords

  • UT-Hybrid-D
  • BiVO
  • PEC devices
  • Performance
  • Silicon geometry
  • Sulfite oxidation
  • BiOI

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