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The production of nitrous oxide, N2O, via NH3 oxidation is not on a practical scale due to the lack of a suitable catalyst. Instead, it is produced via thermal decomposition of NH4NO3, rendering N2O too costly and limiting its prospective uses. Herein, we report CeO2‐supported Au nanoparticles (2–3 nm) as a highly selective catalyst for low‐temperature NH3 oxidation to N2O, exhibiting two orders of magnitude higher space–time yield than the state‐of‐the‐art Mn−Bi/α‐Al2O3 and remarkable stability over 70 h on stream. The reaction proceeds via a Mars–van Krevelen mechanism, with the density of interfacial Auδ+ species and the oxygen storage capacity of CeO2 identified as the key performance descriptors. The latter could be enhanced by cobalt doping, improving the catalytic activity and setting a new benchmark for N2O productivity. These findings establish NH3 oxidation as an efficient process for N2O manufacture and facilitate its broader utilization in selective oxidations. [ABSTRACT FROM AUTHOR]

Keywords: Ammonia Oxidation; Au/CeO2; Metal-Support Interface; Nitrous Oxide; Reaction Mechanisms EN Ammonia Oxidation Au/CeO2 Metal-Support Interface Nitrous Oxide Reaction Mechanisms 1 1 1 04/27/22 20220502 NES 220502 B Ein Spiel zweier Hälften b Die direkte Oxidation von Ammoniak eröffnet einen Weg zur kostengünstigen und effizienten Produktion von Stickstoffoxid, einem vielversprechenden Reagens für selektive Oxidationsreaktionen. Rücktitelbild: Ceria-Supported Gold Nanoparticles as a Superior Catalyst for Nitrous Oxide Production via Ammonia Oxidation (Angew. Ammonia Oxidation, Au/CeO2, Metal-Support Interface, Nitrous Oxide, Reaction Mechanisms. [Extracted from the article]

Ammonia Oxidation, Au/CeO2, Metal-Support Interface, Nitrous Oxide, Reaction Mechanisms Keywords: Ammonia Oxidation; Au/CeO2; Metal-Support Interface; Nitrous Oxide; Reaction Mechanisms EN Ammonia Oxidation Au/CeO2 Metal-Support Interface Nitrous Oxide Reaction Mechanisms 1 1 1 04/27/22 20220502 NES 220502 B A game of two halves b Direct ammonia oxidation unlocks a pathway towards affordable and efficient production of nitrous oxide, a highly promising agent for selective oxidation reactions, but necessitates the development of suitable catalysts. Back Cover: Ceria-Supported Gold Nanoparticles as a Superior Catalyst for Nitrous Oxide Production via Ammonia Oxidation (Angew. [Extracted from the article]

The simple deposition of tailored Rh or Pt nanoparticles (NP) on γ-Al2O3 results in active, selective, and stable catalysts for partial oxidation of methane (POM) to syngas. The NP were prepared by the ethylene glycol method in strong alkaline solution. This approach was found to be a promising way of providing active metallic NP for catalyzing the POM reaction. NP sizes determined by small angle X-ray scattering (SAXS) in solution and by transmission electron microscopy (TEM) on alumina were very close. This result highlights the possibility of easy pre-characterization of NP by the former method. Supported Rh NP are intrinsically more active in the POM reaction than Pt NP and also showed a superior performance compared with a conventionally prepared Rh catalyst, even if the latter had been pre-reduced. Mechanistic investigations in the temporal analysis of products (TAP) reactor indicate that the higher selectivity of well-defined Rh-NP is determined by their lower activity for consecutive CO transformations. [ABSTRACT FROM AUTHOR]

Abstract: In order to identify factors governing selectivity of an oxygen-conducting perovskite BaCo x Fe y Zr z O3−δ (BCFZ) membrane in the partial oxidation of methane and ethane, mechanistic aspects of product formation in these reactions were investigated with a millisecond time resolution using the temporal analysis of products (TAP) reactor. It was found that the selectivity depends on: (i) reduction degree of the perovskite surface; the higher the reduction degree, the higher the ethane and ethylene selectivity in methane and ethane oxidation, respectively, and (ii) contact time; short contact times favor partial selective oxidation. The influence of contact time on the ethylene selectivity in ethane oxidation at degrees of ethane conversion above 85% was experimentally proven in hollow fiber and disk membranes, which differ in the contact times. The low activity and selectivity in methane oxidation in the BCFZ perovskite membrane reactor were significantly increased, when the membrane on the hydrocarbon side was coated by a Ni-based steam reforming catalyst. This catalyst fulfils a double role: (i) it increases the oxygen transport through the perovskite membrane due to the high oxygen consumption, and (ii) it accelerates syngas production via deep methane oxidation followed by dry and steam reforming of methane. The syngas selectivity increases with an increase in the catalyst reduction degree, which is determined by the ratio of the rate of methane oxidation to the rate of oxygen permeation through the membrane. [Copyright &y& Elsevier]