Tuning the Selectivity of Nitrate Reduction via Fine Composition Control of RuPdNP Catalysts.

Autor: Troutman JP; Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, 301 E. Dean Keeton Street Stop C1700, Austin, TX, 78712, USA.; Department of Chemistry, The University of Texas at Austin, 105 E. 24th Street Stop A5300, Austin, TX, 78712, USA., Mantha JSP; Department of Chemistry, The University of Texas at Austin, 105 E. 24th Street Stop A5300, Austin, TX, 78712, USA., Li H; Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Sendai, 980-8577, Japan., Henkelman G; Department of Chemistry, The University of Texas at Austin, 105 E. 24th Street Stop A5300, Austin, TX, 78712, USA., Humphrey SM; Department of Chemistry, The University of Texas at Austin, 105 E. 24th Street Stop A5300, Austin, TX, 78712, USA., Werth CJ; Department of Civil, Architectural, and Environmental Engineering, The University of Texas at Austin, 301 E. Dean Keeton Street Stop C1700, Austin, TX, 78712, USA.
Jazyk: angličtina
Zdroj: Small (Weinheim an der Bergstrasse, Germany) [Small] 2024 Jun; Vol. 20 (26), pp. e2308593. Date of Electronic Publication: 2024 Feb 07.
DOI: 10.1002/smll.202308593
Abstrakt: Herein, aqueous nitrate (NO 3 - ) reduction is used to explore composition-selectivity relationships of randomly alloyed ruthenium-palladium nanoparticle catalysts to provide insights into the factors affecting selectivity during this and other industrially relevant catalytic reactions. NO 3 - reduction proceeds through nitrite (NO 2 - ) and then nitric oxide (NO), before diverging to form either dinitrogen (N 2 ) or ammonium (NH 4 + ) as final products, with N 2 preferred in potable water treatment but NH 4 + preferred for nitrogen recovery. It is shown that the NO 3 - and NO starting feedstocks favor NH 4 + formation using Ru-rich catalysts, while Pd-rich catalysts favor N 2 formation. Conversely, a NO 2 - starting feedstock favors NH 4 + at ≈50 atomic-% Ru and selectivity decreases with higher Ru content. Mechanistic differences have been probed using density functional theory (DFT). Results show that, for NO 3 - and NO feedstocks, the thermodynamics of the competing pathways for N-H and N-N formation lead to preferential NH 4 +  or N 2 production, respectively, while Ru-rich surfaces are susceptible to poisoning by NO 2 - feedstock, which displaces H atoms. This leads to a decrease in overall reduction activity and an increase in selectivity toward N 2 production. Together, these results demonstrate the importance of tailoring both the reaction pathway thermodynamics and initial reactant binding energies to control overall reaction selectivity.
(© 2024 Wiley‐VCH GmbH.)
Databáze: MEDLINE
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