Promoted N[triple bond]N activation by oxygen and boosted ammonia production over Bi4O5Br2

Yuan, Chen; Lu, Zilin; Jiang, Wenjun; Ibhadon, Alex O.; Teng, Fei

Abstract

Nitrogen photoreduction method is recognized as a safe, environmentally friendly and sustainable technology for ammonia production. For this method, nevertheless, it is a big challenge to efficaciously activate the N[tbnd]N triple bond. In this work, we mainly investigate the activation of N[tbnd]N bond and the ammonia production reaction over Bi4O5Br2. Under an N2/O2 atmosphere, the ammonia yield reaches 122.8 μmol L−1 over Bi4O5Br2, which is 2.55 times than that under a N2 atmosphere (34.6 μmol L−1). Theory calculation results further verify that the activation of N[tbnd]N bond is obviously improved by the presence of oxygen. It is proposed that the presence of oxygen, as an electron transfer bridge, facilitates the activation of nitrogen, and thus accelerating nitrogen photoreduction reaction. Additionally, in the methanol/water system, the ammonia production rates of Bi4O5Br2 reaches 8597.5 μmol g−1L−1h−1, which is 6 times higher than that in pure water (1228.5 μmol L−1g−1h−1). We assume that methanol as a hole scavenger has efficiently prevented the oxidation of ammonia, thus significantly accelerating the nitrogen photoreduction reaction. This work demonstrates that directly using air as feed gas is a very easy and cost-effective strategy for ammonia production.

Citation

Yuan, C., Lu, Z., Jiang, W., Ibhadon, A. O., & Teng, F. (2021). Promoted N[triple bond]N activation by oxygen and boosted ammonia production over Bi4O5Br2. Molecular Catalysis, 515, Article 111913. https://doi.org/10.1016/j.mcat.2021.111913

• Journal Article Type: Article
• Acceptance Date: Sep 16, 2021
• Online Publication Date: Sep 25, 2021
• Publication Date: 2021-10
• Deposit Date: May 3, 2022
• Journal: Molecular Catalysis
• Print ISSN: 2468-8231
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 515
• Article Number: 111913
• DOI: https://doi.org/10.1016/j.mcat.2021.111913
• Keywords: Bi4O5Br2; Solar energy; Nitrogen photoreduction; N triple bond N bond activation; Oxygen
• Public URL: https://hull-repository.worktribe.com/output/3850045