Mengyang Xia, Chao Zhao, Hang Xiao, Wei Liu, Yang Li, He Li, Honghui Ou, Guidong Yang
{"title":"Manipulating Superexchange Interaction of Ru–O–Fe Sites for Enhanced Electrocatalytic Nitrate-to-Ammonia Selectivity","authors":"Mengyang Xia, Chao Zhao, Hang Xiao, Wei Liu, Yang Li, He Li, Honghui Ou, Guidong Yang","doi":"10.1021/acscatal.4c02698","DOIUrl":null,"url":null,"abstract":"Fe-based catalysts are promising for electrochemical nitrate reduction, but their selectivity is limited by the multielectron/proton transfer reaction steps. Here, we propose optimizing the <i>e</i><sub><i>g</i></sub>-orbital electron occupancy by regulating the superexchange interaction of the Fe site to improve the NH<sub>3</sub> production performance. Our experimental and theoretical prediction results confirmed that Ru–O–Fe sites in double perovskite iron oxides (LaFe<sub>0.9</sub>Ru<sub>0.1</sub>O<sub>3</sub>) have more significant superexchange interactions, mainly manifested by O-anion-mediated electron transfer from Ru to Fe cations. Ru alters Fe’s spin configuration through Ru–O–Fe orbital hybridization, transitioning from a high-spin (HS, <i>e</i><sub><i>g</i></sub> ≈ 2) to an intermediate-spin state (<i>e</i><sub><i>g</i></sub> ≈ 1). This transition promotes NO<sub>3</sub><sup>–</sup> adsorption and lowers the hydrogenation energy barrier of the *NO intermediate. Consequently, LaFe<sub>0.9</sub>Ru<sub>0.1</sub>O<sub>3</sub> could efficiently convert NO<sub>3</sub><sup>–</sup> to NH<sub>3</sub>, achieving rates of 0.75 mmol·h<sup>–1</sup>·cm<sup>–2</sup> with a Faraday efficiency of 98.5%. Remarkably, the NH<sub>3</sub> selectivity was as high as 90.7%, which represents almost the best catalyst to date.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":null,"pages":null},"PeriodicalIF":11.3000,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acscatal.4c02698","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Fe-based catalysts are promising for electrochemical nitrate reduction, but their selectivity is limited by the multielectron/proton transfer reaction steps. Here, we propose optimizing the eg-orbital electron occupancy by regulating the superexchange interaction of the Fe site to improve the NH3 production performance. Our experimental and theoretical prediction results confirmed that Ru–O–Fe sites in double perovskite iron oxides (LaFe0.9Ru0.1O3) have more significant superexchange interactions, mainly manifested by O-anion-mediated electron transfer from Ru to Fe cations. Ru alters Fe’s spin configuration through Ru–O–Fe orbital hybridization, transitioning from a high-spin (HS, eg ≈ 2) to an intermediate-spin state (eg ≈ 1). This transition promotes NO3– adsorption and lowers the hydrogenation energy barrier of the *NO intermediate. Consequently, LaFe0.9Ru0.1O3 could efficiently convert NO3– to NH3, achieving rates of 0.75 mmol·h–1·cm–2 with a Faraday efficiency of 98.5%. Remarkably, the NH3 selectivity was as high as 90.7%, which represents almost the best catalyst to date.
期刊介绍:
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.