Challenges of fitting a Nitrided austenitic stainless steel Mössbauer Spectrum

Olzon-Dionysio, D.; Souza, Solange de; Olzon-Dionysio, M.

doi:10.1007/s10751-021-01762-2

Cited by 2 publications

(2 citation statements)

References 34 publications

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“…The authors have cited additional references within the Supporting Information. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] SAMBA beamline. We acknowledge the Paul Scherrer Institut, Villigen, Switzerland for provision of synchrotron radiation beamtime at beamline SuperXAS (X10DA) of the Swiss Light Source (proposal No.…”

Section: Supporting Informationmentioning

confidence: 99%

Mechanocatalytic Synthesis of Ammonia: State of the Catalyst During Reaction and Deactivation Pathway

Reichle,

Kang,

Demirbas

et al. 2024

Angew Chem Int Ed

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Ammonia synthesis holds significant importance for both agricultural fertilizer production and emerging green energy applications. Here, we present a comprehensive characterization of a catalyst for mechanochemical ammonia synthesis, based on Cs‐promoted Fe. The study sheds light on the catalyst's dynamic evolution under reaction conditions and the origin of deactivation. Initially, elemental Cs converts to CsH, followed by partial CsOH formation due to trace oxygen impurities on the surface of the Fe metal and the equipment. Concurrently, the mechanical milling process comminutes Fe, exposing fresh metallic Fe surfaces. This comminution correlates with an induction period observed during ammonia formation. Critical to the study, degradation of active Cs promoter species (CsH and CsNH2) into inactive CsOH emerged as the primary deactivation mechanism. By increasing the Cs content from 2.2 mol% to 4.2 mol%, we achieved stable, continuous ammonia synthesis for nearly 90 hours, showcasing one of the longest‐running mechanocatalytic gas phase reactions. Studies of the temperature dependence of the reaction revealed negligible bulk temperature influence in the range of ‐10°C to 100°C, highlighting the dominance of mechanical action over bulk thermal effects. This study offers insights into the complex interplay between mechanical processing, reactive species, and deactivation mechanisms in mechanocatalytic ammonia synthesis.

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