Author, as appears in the article.: Tzaguy, Avra; Masip-Sanchez, Albert; Avram, Liat; Sole-Daura, Albert; Lopez, Xavier; Poblet, Josep M; Neumann, Ronny
Department: Química Física i Inorgànica
URV's Author/s: López Fernández, Javier / Masip Sánchez, Albert / Poblet Rius, Josep Maria / Solé Daura, Albert
Keywords: Activation Clean water and sanitation Conversion Coordination Derivatives Electrochemical reduction Molybdenum N-2 N-2-to-nh Nitrogen reduction Potentials
Abstract: The electrification of ammonia synthesis is a key target for its decentralization and lowering impact on atmospheric CO2 concentrations. The lithium metal electrochemical reduction of nitrogen to ammonia using alcohols as proton/electron donors is an important advance, but requires rather negative potentials, and anhydrous conditions. Organometallic electrocatalysts using redox mediators have also been reported. Water as a proton and electron donor has not been demonstrated in these reactions. Here a N-2 to NH3 electrocatalytic reduction using an inorganic molecular catalyst, a tri-iron substituted polyoxotungstate, {SiFe3W9}, is presented. The catalyst requires the presence of Li+ or Na+ cations as promoters through their binding to {SiFe3W9}. Experimental NMR, CV and UV-vis measurements, and MD simulations and DFT calculations show that the alkali metal cation enables the decrease of the redox potential of {SiFe3W9} allowing the activation of N-2. Controlled potential electrolysis with highly purified N-14(2) and N-15(2) ruled out formation of NH3 from contaminants. Importantly, using Na+ cations and polyethylene glycol as solvent, the anodic oxidation of water can be used as a proton and electron donor for the formation of NH3. In an undivided cell electrolyzer under 1 bar N-2, rates of NH3 formation of 1.15 nmol sec(-1) cm(-2), faradaic efficiencies of similar to 25%, 5.1 equiv of NH3 per equivalent of {SiFe3W9} in 10 h, and a TOF of 64 s(-1) were obtained. The future development of suitable high surface area cathodes and well solubilized N-2 and the use of H2O as the reducing agent are important keys to the future deployment of an electrocatalytic ammonia synthesis.
Thematic Areas: Astronomia / física Biochemistry Catalysis Chemistry Chemistry (all) Chemistry (miscellaneous) Chemistry, multidisciplinary Ciência de alimentos Ciências agrárias i Ciências biológicas i Ciências biológicas ii Colloid and surface chemistry Engenharias ii Engenharias iii Engenharias iv Farmacia General chemistry Interdisciplinar Materiais Química
licence for use: https://creativecommons.org/licenses/by/3.0/es/
Author's mail: javier.lopez@urv.cat josepmaria.poblet@urv.cat albert.masip@urv.cat albert.masip@urv.cat
Author identifier: 0000-0003-0322-6796 0000-0002-4533-0623
Record's date: 2025-02-17
Paper version: info:eu-repo/semantics/publishedVersion
Paper original source: Journal Of The American Chemical Society. 145 (36): 19912-19924
APA: Tzaguy, Avra; Masip-Sanchez, Albert; Avram, Liat; Sole-Daura, Albert; Lopez, Xavier; Poblet, Josep M; Neumann, Ronny (2023). Electrocatalytic Reduction of Dinitrogen to Ammonia with Water as Proton and Electron Donor Catalyzed by a Combination of a Tri-ironoxotungstate and an Alkali Metal Cation. Journal Of The American Chemical Society, 145(36), 19912-19924. DOI: 10.1021/jacs.3c06167
Licence document URL: https://repositori.urv.cat/ca/proteccio-de-dades/
Entity: Universitat Rovira i Virgili
Journal publication year: 2023
Publication Type: Journal Publications