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 language | English |
---|---|
Pages (from-to) | 309-314 |
Number of pages | 6 |
Journal | Journal of Energy Chemistry |
Volume | 26 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1 Mar 2017 |
Keywords
- Ag
- Core–Shell
- Mechanism
- Photocatalysis
- Photoelectrochemistry
- Plasmon
- SiO
- Stability
- Water-splitting
- WO
- ZnO