Enhancing activity in a nanostructured BiVO4 photoanode with a coating of microporous Al2O3

Murilo F. Gromboni, Dyovani Coelho, Lucia H. Mascaro, Adam Pockett, Frank Marken

Research output: Contribution to journalArticle

14 Citations (Scopus)
143 Downloads (Pure)

Abstract

Nanostructured semiconductor photoanodes play an important role in solar fuel generation, and the design of the semiconductor − aqueous electrolyte interface can be crucial in enhancing the energy conversion efficiency. We have investigated the effects on photoelectrochemical oxygen evolution for monoclinic nanostructured BiVO4 films uncoated and coated with microporous sol-gel Al2O3 “over-layers”. Variation of the thickness of the Al2O3 coating (formed by surface sol-gel deposition and annealing at 435 °C) led to a reduction of pseudo-capacitance and allowed optimization of the quantum efficiency. Exploration of the photocurrent enhancement as a function of applied potential reveals two distinct potential domains/mechanisms: (i) a low bias region enhancement effect (assigned to a lowering of the rate of external recombination of electrons with oxygen) and (ii) a high bias region of enhancement (assigned to higher charge carrier mobility due to less trapping in surface states).

Original languageEnglish
Pages (from-to)133-140
Number of pages8
JournalApplied Catalysis B: Environmental
Volume200
Early online date24 Jun 2016
DOIs
Publication statusPublished - 1 Jan 2017

Keywords

  • Ceramic coating
  • Microporous membrane
  • Photo-kinetics
  • Photocatalysis
  • Solar energy
  • Water splitting

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