Stability of Ag@SiO2 core–shell particles in conditions of photocatalytic overall water-splitting

Sun Young Park, Kai Han, Devin B. O'Neill, Guido Mul*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

11 Citations (Scopus)
1 Downloads (Pure)

Abstract

Core–shell nanoparticles containing plasmonic metals (Ag or Au) have been frequently reported to enhance performance of photo-electrochemical (PEC) devices. However, the stability of these particles in water-splitting conditions is usually not addressed. In this study we demonstrate that Ag@SiO2 core–shell particles are instable in the acidic conditions in which WO3-based PEC cells typically operate, Ag in the core being prone to oxidation, even if the SiO2 shell has a thickness in the order of 10 nm. This is evident from in situ voltammetry studies of several anode composites. Similar to the results of the PEC experiments, the Ag@SiO2 core–shell particles are instable in slurry-based, Pt/ZnO induced photocatalytic water-splitting. This was evidenced by in situ photodeposition of Ag nanoparticles on the Pt-loaded ZnO catalyst, observed in TEM micrographs obtained after reaction. We explain the instability of Ag@SiO2 by OH-radical induced oxidation of Ag, yielding dissolved Ag+. Our results imply that a decrease in shell permeability for OH-radicals is necessary to obtain stable, Ag-based plasmonic entities in photo-electro-chemical and photocatalytic water splitting.

Original languageEnglish
Pages (from-to)309-314
Number of pages6
JournalJournal of Energy Chemistry
Volume26
Issue number2
DOIs
Publication statusPublished - 1 Mar 2017

Keywords

  • Ag
  • Core–Shell
  • Mechanism
  • Photocatalysis
  • Photoelectrochemistry
  • Plasmon
  • SiO
  • Stability
  • Water-splitting
  • WO
  • ZnO

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