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Highly Selective Ammonia Oxidation on BiVO 4 Photoanodes Co-catalyzed by Trace Amounts of Copper Ions.
- Source :
-
Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2024 Jan 22; Vol. 63 (4), pp. e202316218. Date of Electronic Publication: 2023 Dec 19. - Publication Year :
- 2024
-
Abstract
- High-efficient photoelectrocatalytic direct ammonia oxidation reaction (AOR) conducted on semiconductor photoanodes remains a substantial challenge. Herein, we develop a strategy of simply introducing ppm levels of Cu ions (0.5-10 mg/L) into NH <subscript>3</subscript> solutions to significantly improve the AOR photocurrent of bare BiVO <subscript>4</subscript> photoanodes from 3.4 to 6.3 mA cm <superscript>-2</superscript> at 1.23 V <subscript>RHE</subscript> , being close to the theoretical maximum photocurrent of BiVO <subscript>4</subscript> (7.5 mA cm <superscript>-2</superscript> ). The surface charge-separation efficiency has reached 90 % under a low bias of 0.8 V <subscript>RHE</subscript> . This AOR exhibits a high Faradaic efficiency (FE) of 93.8 % with the water oxidation reaction (WOR) being greatly suppressed. N <subscript>2</subscript> is the main AOR product with FEs of 71.1 % in aqueous solutions and FEs of 100 % in non-aqueous solutions. Through mechanistic studies, we find that the formation of Cu-NH <subscript>3</subscript> complexes possesses preferential adsorption on BiVO <subscript>4</subscript> surfaces and efficiently competes with WOR. Meanwhile, the cooperation of BiVO <subscript>4</subscript> surface effect and Cu-induced coordination effect activates N-H bonds and accelerates the first rate-limiting proton-coupled electron transfer for AOR. This simple strategy is further extended to other photoanodes and electrocatalysts.<br /> (© 2023 Wiley-VCH GmbH.)
Details
- Language :
- English
- ISSN :
- 1521-3773
- Volume :
- 63
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- Angewandte Chemie (International ed. in English)
- Publication Type :
- Academic Journal
- Accession number :
- 38069527
- Full Text :
- https://doi.org/10.1002/anie.202316218