光电流
催化作用
水溶液
法拉第效率
吸附
铜
离子
氨
化学
氧化还原
电子转移
无机化学
电化学
氨生产
光化学
材料科学
电极
物理化学
光电子学
有机化学
生物化学
作者
Lei Wu,Qianqian Li,Kun Dang,Daojian Tang,Chuncheng Chen,Yuchao Zhang,Jincai Zhao
标识
DOI:10.1002/anie.202316218
摘要
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.
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