Direct observation of the chemical transformations in BiVO4 photoanodes upon prolonged light-aging treatments

Exposing BiVO photoanodes to light-aging treatments is known to produce a significant photocurrent enhancement. Until now, the interpretation given to this phenomenon is associated to the formation of oxygen vacancies and little is reported about chemical changes in the material. Herein, the chemica...

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Authors: Arcas, Ramón, Cardenas-Morcoso, Drialys, Spadaro, Maria Chiara|||0000-0002-6540-0377, García-Tecedor, Miguel|||0000-0002-9664-4665, Mesa, Camilo A.|||0000-0002-8450-2563, Arbiol i Cobos, Jordi|||0000-0002-0695-1726, Fabregat-Santiago, Francisco, Giménez, Sixto|||0000-0002-4522-3174, Mas-Marzá, Elena
Format: article
Publication Date:2022
Country:España
Institution:Universitat Autònoma de Barcelona
Repository:Dipòsit Digital de Documents de la UAB
Language:English
OAI Identifier:oai:ddd.uab.cat:266327
Online Access:https://ddd.uab.cat/record/266327
https://dx.doi.org/urn:doi:10.1002/solr.202200132
Access Level:Open access
Keyword:Bi segregation
BiVO4
Light-aging treatments
Oxygen vacancies
Description
Summary:Exposing BiVO photoanodes to light-aging treatments is known to produce a significant photocurrent enhancement. Until now, the interpretation given to this phenomenon is associated to the formation of oxygen vacancies and little is reported about chemical changes in the material. Herein, the chemical segregation of Bi species toward the surface upon light-aging treatment is demonstrated, which takes place with the concomitant formation of intra-bandgap states associated to the oxygen vacancies. It is further demonstrated that these intra-bandgap states are photoactive and generate photocurrent under infrared excitation. These results highlight the importance of understanding light-induced effects while employing multinary metal oxide photoelectrodes.