ZnO/Ag/Ag2WO4 photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation

Rania E Adam; Mahsa Pirhashemi; Sami Elhag; Xianjie Liu; Aziz Habibi-Yangjeh; Magnus Willander; Omer Nur

doi:10.1039/c8ra10141h

ZnO/Ag/Ag₂WO₄ photo-electrodes with plasmonic behavior for enhanced photoelectrochemical water oxidation

RSC Adv. 2019 Mar 12;9(15):8271-8279. doi: 10.1039/c8ra10141h.

Authors

Rania E Adam¹, Mahsa Pirhashemi², Sami Elhag¹, Xianjie Liu³, Aziz Habibi-Yangjeh², Magnus Willander¹, Omer Nur¹

Affiliations

¹ Department of Sciences and Technology, Linköping University, Campus Norrköping SE-601 74 Norrköping Sweden rania.elhadi.adam@liu.se omer.nour@liu.se.
² Department of Chemistry, Faculty of Sciences, University of Mohaghegh Ardabili P. O. Box 179 Ardabil Iran.
³ Department of Physics, Chemistry and Biology (IFM), Linköping University 58183 Linköping Sweden.

Abstract

Ag-based compounds are excellent co-catalyst that can enhance harvesting visible light and increase photo-generated charge carrier separation owing to its surface plasmon resonance (SPR) effect in photoelectrochemical (PEC) applications. However, the PEC performance of a ZnO/Ag/Ag₂WO₄ heterostructure with SPR behavior has not been fully studied so far. Here we report the preparation of a ZnO/Ag/Ag₂WO₄ photo-electrode with SPR behavior by a low temperature hydrothermal chemical growth method followed by a successive ionic layer adsorption and reaction (SILAR) method. The properties of the prepared samples were investigated by different characterization techniques, which confirm that Ag/Ag₂WO₄ was deposited on the ZnO NRs. The Ag₂WO₄/Ag/ZnO photo-electrode showed an enhancement in PEC performance compared to bare ZnO NRs. The observed enhancement is attributed to the red shift of the optical absorption spectrum of the Ag₂WO₄/Ag/ZnO to the visible region (>400 nm) and to the SPR effect of surface metallic silver (Ag⁰) particles from the Ag/Ag₂WO₄ that could generate electron-hole pairs under illumination of low energy visible sun light. Finally, we proposed the PEC mechanism of the Ag₂WO₄/Ag/ZnO photo-electrode with an energy band structure and possible electron-hole separation and transportation in the ZnO/Ag/Ag₂WO₄ heterostructure with SPR effect for water oxidation.