Ag(I) ions working as a hole-transfer mediator in photoelectrocatalytic water oxidation on WO3 film

Ag(I) is commonly employed as an electron scavenger to promote water oxidation. In addition to its straightforward role as an electron acceptor, Ag(I) can also capture holes to generate the high-valent silver species. Herein, we demonstrate photoelectrocatalytic (PEC) water oxidation and concurrent...

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Bibliographic Details
Authors: Monllor-Satoca, Damián, Choi, Wonyong, Park, Hyunwoong, Jeon, Tae Hwa, Moon, Gun–hee, Kim, Wooyul, Kim, Hyoung–il, Bahnemann, Detlef W.
Format: article
Status:Published version
Publication Date:2020
Country:España
Institution:Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya)
Repository:Recercat. Dipósit de la Recerca de Catalunya
OAI Identifier:oai:recercat.cat:20.500.14342/1116
Online Access:http://hdl.handle.net/20.500.14342/1116
https://doi.org/10.1038/s41467-020-14775-2
Access Level:Open access
Keyword:Electrocatàlisi
Fotocatàlisi
Catalytic mechanisms
Electrocatalysis
Photocatalysis
54
Description
Summary:Ag(I) is commonly employed as an electron scavenger to promote water oxidation. In addition to its straightforward role as an electron acceptor, Ag(I) can also capture holes to generate the high-valent silver species. Herein, we demonstrate photoelectrocatalytic (PEC) water oxidation and concurrent dioxygen evolution by the silver redox cycle where Ag(I) acts as a hole-transfer mediator. Ag(I) enhances the PEC performance of WO3 electrodes at 1.23 V vs. RHE with increasing O2 evolution, while forming Ag(II) complexes (AgIINO3+). Upon turning off both light and potential bias, the photocurrent immediately drops to zero, whereas O2 evolution continues over ~10 h with gradual bleaching of the colored complexes. This phenomenon is observed neither in the Ag(I)-free PEC reactions nor in the photocatalytic (i.e., bias-free) reactions with Ag(I). This study finds that the role of Ag(I) is not limited as an electron scavenger and calls for more thorough studies on the effect of Ag(I).

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