In Situ Formation of Oxygen Vacancies Achieving Near-Complete Charge Separation in Planar BiVO<sub>4</sub> Photoanodes.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32406092.
- Also identified by DOI 10.1002/adma.202001385.
- No licence information is recorded for this record.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Despite a suitable bandgap of bismuth vanadate (BiVO<sub>4</sub> ) for visible light absorption, most of the photogenerated holes in BiVO<sub>4</sub> photoanodes are vanished before reaching the surfaces for oxygen evolution reaction due to the poor charge separation efficiency in the bulk. Herein, a new sulfur oxidation strategy is developed to prepare planar BiVO<sub>4</sub> photoanodes with in situ formed oxygen vacancies, which increases the majority charge carrier density and photovoltage, leading to a record charge separation efficiency of 98.2% among the reported BiVO<sub>4</sub> photoanodes. Upon loading NiFeO<sub>x</sub> as an oxygen evolution cocatalyst, a stable photocurrent density of 5.54 mA cm<sup>-2</sup> is achieved at 1.23 V versus the reversible hydrogen electrode (RHE) under AM 1.5 G illumination. Remarkably, a dual-photoanode configuration further enhances the photocurrent density up to 6.24 mA cm<sup>-2</sup> , achieving an excellent applied bias photon-to-current efficiency of 2.76%. This work demonstrates a simple thermal treatment approach to generate oxygen vacancies for the design of efficient planar photoanodes for solar hydrogen production.