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- Title
Highly Selective Ammonia Oxidation on BiVO<sub>4</sub> Photoanodes Co‐catalyzed by Trace Amounts of Copper Ions.
- Authors
Wu, Lei; Li, Qianqian; Dang, Kun; Tang, Daojian; Chen, ChunCheng; Zhang, Yuchao; Zhao, Jincai
- 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 NH3 solutions to significantly improve the AOR photocurrent of bare BiVO4 photoanodes from 3.4 to 6.3 mA cm−2 at 1.23 VRHE, being close to the theoretical maximum photocurrent of BiVO4 (7.5 mA cm−2). The surface charge‐separation efficiency has reached 90 % under a low bias of 0.8 VRHE. This AOR exhibits a high Faradaic efficiency (FE) of 93.8 % with the water oxidation reaction (WOR) being greatly suppressed. N2 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−NH3 complexes possesses preferential adsorption on BiVO4 surfaces and efficiently competes with WOR. Meanwhile, the cooperation of BiVO4 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.
- Subjects
COPPER ions; OXIDATION of water; AMMONIA; OXIDATION; CHARGE exchange; PHOTOELECTROCHEMISTRY; PHOTOCATHODES
- Publication
Angewandte Chemie, 2024, Vol 136, Issue 4, p1
- ISSN
0044-8249
- Publication type
Article
- DOI
10.1002/ange.202316218