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The use of ethane as a platform molecule for the manufacture of polyvinyl chloride (PVC) is a longstanding challenge, which would allow to reduce the raw material costs and CO2 emissions to produce this plastic. Herein, we discover that rare earth oxychlorides catalyze in a selective (up to 90 %) and stable (>50 h on stream) manner the reaction of ethane and molecular chlorine into 1,2‐dichloroethane, which, upon established cracking, will translate into an order of magnitude higher vinyl chloride productivity compared to ethane oxychlorination technologies. In addition, representative europium oxychloride was supported on suitable carriers and was demonstrated to be selective (up to 90 %) and stable (>40 h on stream) in extrudate form. These findings bring the ethane‐based production of PVC one step closer to implementation. [ABSTRACT FROM AUTHOR]

Rücktitelbild: Ethane-Based Catalytic Process for Vinyl Chloride Manufacture (Angew. Catalytic ethane chlorination, ethylene dichloride, natural gas, polyvinyl chloride, rare-earth oxychlorides Keywords: catalytic ethane chlorination; ethylene dichloride; natural gas; polyvinyl chloride; rare-earth oxychlorides EN catalytic ethane chlorination ethylene dichloride natural gas polyvinyl chloride rare-earth oxychlorides 24536 24536 1 10/27/21 20211102 NES 211102 B Gas-to-PVC b Im Forschungsartikel auf S. 24291 berichten Guido Zichittella und Javier Pérez-Ramírez über die herausragende Aktivität von Seltenerd-Oxychlorid-Katalysatoren für die selektive Umwandlung von Ethan in 1,2-Dichlorethan, einen Vorläufer des Vinylchlorid-Monomers. [Extracted from the article]

Chemistry, a vital tool for sustainable development, faces a challenge due to the lack of clear guidance on actionable steps, hindering the optimal adoption of sustainability practices across its diverse facets from discovery to implementation. This Scientific Perspective explores established frameworks and principles, proposing a conciliated set of triple E priorities anchored on Environmental, Economic, and Equity pillars for research and decision making. We outline associated metrics, crucial for quantifying impacts, classifying them according to their focus areas and scales tackled. Emphasizing catalysis as a key driver of sustainable synthesis of chemicals and materials, we exemplify how triple E priorities can practically guide the development and implementation of processes from renewables conversions to complex customized products. We summarize by proposing a roadmap for the community aimed at raising awareness, fostering academia–industry collaboration, and stimulating further advances in sustainable chemical technologies across their broad scope. [ABSTRACT FROM AUTHOR]

Single‐atom heterogeneous catalysts (SACs) hold promise as sustainable alternatives to metal complexes in organic transformations. However, their working structure and dynamics remain poorly understood, hindering advances in their design. Exploiting the unique features of droplet‐based microfluidics, we present the first in‐situ assessment of a palladium SAC based on exfoliated carbon nitride in Suzuki–Miyaura cross‐coupling using X‐ray absorption spectroscopy. Our results confirm a surface‐catalyzed mechanism, revealing the distinct electronic structure of active Pd centers compared to homogeneous systems, and providing insights into the stabilizing role of ligands and bases. This study establishes a valuable framework for advancing mechanistic understanding of organic syntheses catalyzed by SACs. [ABSTRACT FROM AUTHOR]

C1 coupling reactions over zeolite catalysts are central to sustainable chemical production strategies. However, questions persist regarding the involvement of CO in ketene formation, and the impact of this elusive oxygenate intermediate on reactivity patterns. Using operando photoelectron photoion coincidence spectroscopy (PEPICO), we investigate the role of CO in methyl chloride conversion to hydrocarbons (MCTH), a prospective process for methane valorization with a reaction network akin to methanol to hydrocarbons (MTH) but without oxygenate intermediates. Our findings reveal the transformative role of CO in MCTH at the low pressures, inducing ketene formation in MCTH and boosting olefin production, confirming the Koch carbonylation step in the initial stages of C1 coupling. We uncover pressure‐dependent product distributions driven by CO‐induced ketene formation, and its subsequent desorption from the zeolite surface, which is enhanced at low pressure. Inspired by the above results, extension of the co‐feeding approach to CH3OH as another simple oxygenate showcases the additional potential for improved catalyst stability in MCTH at ambient pressure. [ABSTRACT FROM AUTHOR]

Catalytic hydrogenolysis has the potential to convert high‐density polyethylene (HDPE), which comprises about 30 % of plastic waste, into valuable alkanes. Most investigations have focused on increasing activity for lab grade HDPEs displaying low molecular weight, with limited mechanistic understanding of the product distribution. No efficient catalyst is available for consumer grades due to their lower reactivity. This study targets HDPE used in bottle caps, a waste form generated globally at a rate of approximately one million units per hour. Ultrafine ruthenium particles (1 nm) supported on titania (anatase) achieved up to 80 % conversion into light alkanes (C1−C45) under mild conditions (498 K, 20 bar H2, 4 h) and were reused for three cycles. Small ruthenium nanoparticles were critical to achieving relevant conversions, as activity sharply decreased with particle size. Selectivity commonalities and peculiarities across HDPE grades were disclosed by a reaction modelling approach applied to products. Isomerization cedes to backbone scission as the reaction progresses. Within this trend, low molecular weight favor isomerization whilst high molecular weight favor cleavage. Commercial caps obeyed this trend with decreased activity, anticipating the influence of additives in realistic processing. This study demonstrates effective hydrogenolysis of consumer grade polyethylene and provides selectivity patterns for product control. [ABSTRACT FROM AUTHOR]

Ternäre Pd‐In2O3/ZrO2 Katalysatoren beweisen technologisches Potenzial für die CO2‐basierte Methanolsynthese, wobei die Entwicklung skalierbarer Systeme und das Verständnis komplexer dynamischer Wechselwirkungen zwischen der aktiven Phase, des Promotors und des Trägers der Schlüssel zur Erreichung einer hohen Produktivität sind. Hier zeigen wir, dass durch einfache Imprägnierung hergestellte Pd‐In2O3/ZrO2 Katalysatoren unter CO2‐Hydrierbedingungen eine stabile und selektive Nanoarchitektur bilden, unabhängig von der Reihenfolge der Zugabe von Pd‐ und In‐Komponenten auf den Zirkonoxidträger. Detaillierte operando Charakterisierung und Simulationen deuten auf eine schnelle Umstrukturierung, dessen Treiber die Energie der Metall‐Metalloxid‐Wechselwirkung ist. Die Nähe von InOx‐Schichten auf den entstehenden InPdx‐Partikeln verhindern Leistungsverluste durch Pd‐Sinterung. Weiterhin unterstreichen die Ergebnisse die entscheidende Rolle der reaktionsinduzierten Umstrukturierung in komplexem CO2‐Hydrierkatalysatoren und bieten Einblicke in die optimale Integration von Säure‐Base‐ und Redoxfunktionen für die technische Umsetzung. [ABSTRACT FROM AUTHOR]

Heterogene Einzelatom‐Katalysatoren (single‐atom heterogeneous catalysts, SACs) finden aufgrund ihrer maximalen Reaktivität pro Metallatom und der einfachen Wiederverwendbarkeit großen Anklang in der akademischen Welt. Jedoch führt der Weg von Nanopartikeln oder Metallclustern zu schließlich einzeln isolierten Atomen zwangsläufig zu Veränderungen in der Reaktivität der Katalysatoren, da die physikalische Struktur der aktiven Zentren verändert wird. Hier bewerten wir durch den Vergleich verschiedenster Anwendungen, ob die katalytische Leistungsfähigkeit durch die Verwendung von SACs verbessert oder verschlechtert wird. Zudem stellen wir fest, dass SACs im Allgemeinen einzigartige katalytische Zyklen aufweisen. Die Wahl des Trägermaterials ist maßgebend, da dieses sowohl die elektronischen als auch die sterischen Eigenschaften des Metallzentrums beeinflusst. Außerdem kann der Träger auch als Cokatalysator wirken. Für die Entwicklung neuer SACs, welche die begehrenswerten Eigenschaften ihrer homogenen oder heterogenen Vorgänger vereinen können, müssen all diese Aspekte berücksichtigt werden. Schließlich könnten SACs auch homogene Metallkomplexe in katalytischen Anwendungen ersetzen, bei denen sich die Heterogenisierung als besonders schwierig erweist. Bruch mit der Tradition: Unter Betrachtung der katalytischen Leistung in Reaktionen, die mit heterogenen Einzelatom‐Katalysatoren (SACs) durchgeführt wurden, diskutiert dieser Kurzaufsatz die entscheidenden Faktoren, die zu besserer oder schlechterer Performance verglichen mit heterogenen Metall‐Nanopartikel/Cluster‐Katalysatoren oder homogenen Metallkomplex‐Katalysatoren führen. Es wird gezeigt, dass SACs fast immer einzigartige katalytische Zyklen aufweisen. [ABSTRACT FROM AUTHOR]

Solar‐driven transfer hydrogenation of unsaturated bonds has received considerable attention in the research area of sustainable organic synthesis; however, water, the ultimate green source of hydrogen, has rarely been investigated due to the high barrier associated with splitting of water molecules. We report a carbon‐nitride‐supported palladium single‐atom heterogeneous catalyst with unparalleled performance in photocatalytic water‐donating transfer hydrogenation compared to its nanoparticle counterparts. Isotopic‐labeling experiments and operando nuclear magnetic resonance measurements confirm the direct hydrogenation mechanism using in situ‐generated protons from water splitting under visible‐light irradiation. Density functional theory calculations attribute the high activity to lower barriers for hydrogenation, facilitated desorption of ethylbenzene, and facile hydrogen replenishment from water on the atomic palladium sites. [ABSTRACT FROM AUTHOR]

Chemistry is vital for society , but its practices must align with sustainable development. While attention often focuses on individual pillars—environment, economy, or equity—true sustainability requires alignment across all three. The cover image depicts a sustainability compass, symbolizing the integration of diverse principles into a unified set of triple E priorities proposed by Javier Pérez‐Ramírez et al. in their Scientific Perspective (e202318676) to guide efforts in the chemical sciences...By Sharon Mitchell; Antonio J. Martín; Gonzalo Guillén‐Gosálbez and Javier Pérez‐RamírezReported by Author; Author; Author; Author [Extracted from the article]

The article titled "Titelbild: Droplet-Based Microfluidics Reveals Insights into Cross-Coupling Mechanisms over Single-Atom Heterogeneous Catalysts" discusses the development of in-situ characterization tools for heterogeneous catalysts in organic syntheses. The authors, Andrew J. deMello, Javier Pérez-Ramírez, Sharon Mitchell, and their colleagues, demonstrate the use of an innovative in-situ X-ray absorption spectroscopy approach using droplet-based microfluidics to study palladium single-atom catalysts in Suzuki-Miyaura coupling. The results of their study highlight the feasibility of this technique and its potential to provide new mechanistic insights. Additionally, the article mentions another research article by Shungui Zhou, Yujie Xiong, and their colleagues, which reports on the discovery of non-Fenton-type reactive oxygen species driving abiotic CH4 production, offering a new approach for engineering CH4 production. [Extracted from the article]

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]

The article titled "Consumer Grade Polyethylene Recycling via Hydrogenolysis on Ultrafine Supported Ruthenium Nanoparticles" published in Angewandte Chemie discusses the development of catalysts for the chemical recycling of high-density polyethylene. The researchers, led by Javier Pérez-Ramírez, found that 1-nm ruthenium particles supported on titania can effectively catalyze the hydrogenolysis of plastic caps used in soft drinks, converting them into C1-C45 alkanes. The study also examines the impact of common additives on the catalytic process. The authors of the article are Shibashish D. Jaydev, Antonio J. Martín, Marc-Eduard Usteri, Katia Chikri, Henrik Eliasson, Rolf Erni, and Javier Pérez-Ramírez. [Extracted from the article]

Identification and quantification of redox‐active centers at relevant conditions for catalysis is pivotal to understand reaction mechanisms and requires development of advanced operando methods. Herein, we demonstrate operando EPR spectroscopy as an important technique to quantify the oxidation state of representative CrPO4 and EuOCl catalysts during propane oxychlorination, an attractive route for propylene production. In particular, we show that the space‐time‐yield of C3H6 correlates with the amount of Cr2+ and Eu2+ ions generated over the catalysts during reaction. These results provide a powerful strategy to gather quantitative understanding of selective alkane oxidation, which could potentially be extrapolated to other functionalization approaches and operating conditions. [ABSTRACT FROM AUTHOR]

The electroreduction of carbon dioxide using renewable electricity is an appealing strategy for the sustainable synthesis of chemicals and fuels. Extensive research has focused on the production of ethylene, ethanol and n‐propanol, but more complex C4 molecules have been scarcely reported. Herein, we report the first direct electroreduction of CO2 to 1‐butanol in alkaline electrolyte on Cu gas diffusion electrodes (Faradaic efficiency=0.056 %, j1‐Butanol=−0.080 mA cm−2 at −0.48 V vs. RHE) and elucidate its formation mechanism. Electrolysis of possible molecular intermediates, coupled with density functional theory, led us to propose that CO2 first electroreduces to acetaldehyde‐a key C2 intermediate to 1‐butanol. Acetaldehyde then undergoes a base‐catalyzed aldol condensation to give crotonaldehyde via electrochemical promotion by the catalyst surface. Crotonaldehyde is subsequently electroreduced to butanal, and then to 1‐butanol. In a broad context, our results point to the relevance of coupling chemical and electrochemical processes for the synthesis of higher molecular weight products from CO2. [ABSTRACT FROM AUTHOR]

Chemical modifiers enhance the efficiency of metal catalysts in numerous applications, but their introduction often involves toxic or expensive precursors and complicates the synthesis. Here, we show that a porous boron nitride carrier can directly modify supported palladium nanoparticles, originating unparalleled performance in the continuous semi‐hydrogenation of alkynes. Analysis of the impact of various structural parameters reveals that using a defective high surface area boron nitride and ensuring a palladium particle size of 4–5 nm is critical for maximizing the specific rate. The combined experimental and theoretical analyses point towards boron incorporation from defects in the support to the palladium subsurface, creating the desired isolated ensembles determining the selectivity. This practical approach highlights the unexplored potential of using tailored carriers for catalyst design. [ABSTRACT FROM AUTHOR]

The potential implementation of ruthenium‐based catalysts in polyvinyl chloride production via acetylene hydrochlorination is hindered by their inferior activity and stability compared to gold‐based systems, despite their 4‐fold lower price. Combining in‐depth characterization and kinetic analysis we reveal the superior activity of ruthenium nanoparticles with an optimal size of 1.5 nm hosted on nitrogen‐doped carbon (NC) and identify their deactivation modes: 1) nanoparticle redispersion into inactive single atoms and 2) coke formation at the metal sites. Tuning the density of the NC carrier enables a catalytic encapsulation of the ruthenium nanoparticles into single layer graphene shells at 1073 K that prevent the undesired metal redispersion. Finally, we show that feeding O2 during acetylene hydrochlorination limits coke formation over the nanodesigned ruthenium catalyst, while the graphene layer is preserved, resulting in a stability increase of 20 times, thus rivalling the performance of gold‐based systems. [ABSTRACT FROM AUTHOR]

Keywords: CO2-Hydrierung; Metall-Metalloxid-Wechselwirkungen; Methanolsynthese; Operando Analyse; Pd-In2O3/ZrO2 Katalysator DE CO2-Hydrierung Metall-Metalloxid-Wechselwirkungen Methanolsynthese Operando Analyse Pd-In2O3/ZrO2 Katalysator 1 1 1 10/12/23 20231016 NES 231016 B Developing scalable systems b and understanding dynamic behaviors are crucial for advancing the technological potential of multicomponent catalysts for CO SB 2 sb -based methanol synthesis. In their Research Article (e202306563), Javier Pérez-Ramírez and co-workers show that the reaction-induced restructuring of Pd-In SB 2 sb O SB 3 sb /ZrO SB 2 sb systems, prepared via impregnation, leads to a unique architecture that integrates the necessary acid-base functionality of In SB 2 sb O SB 3 sb with the H SB 2 sb splitting ability of an InPd SB 2 sb alloy, while also ensuring high stability. [Extracted from the article]

Controlling the structure sensitivity of catalyzed reactions over metals is central to developing atom‐efficient chemical processes. Approaching the minimum ensemble size, the properties enter a non‐scalable regime in which each atom counts. Almost all trends in this ultra‐small frontier derive from surface science approaches using model systems, because of both synthetic and analytical challenges. Exploiting the unique coordination chemistry of carbon nitride, we discriminate through experiments and simulations the interplay between the geometry, electronic structure, and reactivity of palladium atoms, dimers, and trimers. Catalytic tests evidence application‐dependent requirements of the active ensemble. In the semi‐hydrogenation of alkynes, the nuclearity primarily impacts activity, whereas the selectivity and stability are affected in Suzuki coupling. This powerful approach will provide practical insights into the design of heterogeneous catalysts comprising well‐defined numbers of atoms. [ABSTRACT FROM AUTHOR]

Die Produktzusammensetzung der direkten Alkanfunktionalisierung durch Oxychlorierung hängt stark von dem verwendeten Halogen ab. Wir zeigen, dass die überragende Olefinselektivität über Eisenphosphatkatalysatoren in Oxychlorierungen eine Konsequenz einer oberflächengebundenen Reaktion ist. Im Unterschied dazu folgt die Alkanaktivierung bei der Oxybromierung einer Radikalkettenreaktion in der Gasphase, wobei ein Gemisch aus Alkylbromid, Cracking‐ und Verbrennungsprodukten entsteht. Die Katalysatoroberflächenchlorierung und die Identifikation von Gasphasenradikalen werden unter Operando‐Bedingungen durch Einsatz verschiedener Methoden mit der katalytischen Leistung korreliert, der es erlaubt, kinetische Untersuchungen mit fortschrittlichen Charakterisierungstechniken, z. B. Prompt‐Gamma‐Aktivierungsanalyse und Photoelektronen‐Photoion‐Koinzidenzspektroskopie, zu vereinen. Die gleichzeitige Erklärung der Gasphasen‐ und Oberflächenanteile durch Dichtefunktionaltheorie zeigt, dass die molekularen Auswirkungen von Chlor entscheidend für die starken Selektivitätsunterschiede sind. Diese Ergebnisse liefern eine Strategie, die es ermöglicht, ein detailliertes mechanistisches Bild eines komplexen Reaktionsnetzwerks zu zeichnen. Bleib auf dem Boden: Durch Kombination von kinetischer Analyse und Operando‐Techniken mit theoretischer Modellierung wird ein Verständnis der Selektivitätskontrolle bei der Oxychlorierung erlangt, die als Folge einer an die Oberfläche gebundenen Reaktion auftritt, sowie über die Radikalreaktionspfade, die die Ethanaktivierung bei der Oxybromierung steuern, was zum beobachteten Produktspektrum führt. [ABSTRACT FROM AUTHOR]

Single‐atom heterogeneous catalysts with well‐defined architectures are promising for deriving structure–performance relationships, but the challenge lies in finely tuning the structural and electronic properties of the metal. To tackle this point, a new approach based on the surface diffusion of gold atoms on different cavities of N‐doped carbon is presented. By controlling the activation temperature, the coordination neighbors (Cl, O, N) and the oxidation state of the metal can be tailored. Semi‐hydrogenation of various alkynes on the single‐atom gold catalysts displays substrate‐dependent catalytic responses; structure insensitive for alkynols with γ‐OH and unfunctionalized alkynes, and sensitive for alkynols with α‐OH. Density functional theory links the sensitivity for alkynols to the strong interaction between the substrate and specific gold‐cavity ensembles, mimicking a molecular recognition pattern that allows to identify the cavity site and to enhance the catalytic activity. [ABSTRACT FROM AUTHOR]

Ethylene and propylene are the key building blocks of the chemical industry, but current processes are unable to close the growing gap between demand and manufacture. Reported herein is an exceptional europium oxychloride (EuOCl) catalyst for the selective (≥95 %) production of light olefins from ethane and propane by oxychlorination chemistry, thus achieving yields of ethylene (90 %) and propylene (40 %) unparalleled by any existing olefin production technology. Moreover, EuOCl is able to process mixtures of methane, ethane, and propane to produce the olefins, thereby reducing separation costs of the alkanes in natural gas. Finally, the EuOCl catalyst was supported on suitable carriers and evaluated in extrudate form, and preserves performance for >150 h under realistic process conditions. [ABSTRACT FROM AUTHOR]

Indium oxide catalyzes acetylene hydrogenation with high selectivity to ethylene (>85 %); even with a large excess of the alkene. In situ characterization reveals the formation of oxygen vacancies under reaction conditions, while an in depth theoretical analysis links the surface reduction with the creation of well-defined vacancies and surrounding In3O5 ensembles, which are considered responsible for this outstanding catalytic function. This behavior, which differs from that of other common reducible oxides, originates from the presence of four crystallographically inequivalent oxygen sites in the indium oxide surface. These resulting ensembles are 1) stable against deactivation, 2) homogeneously and densely distributed, and 3) spatially isolated and confined against transport; thereby broadening the scope of oxides in hydrogenation catalysis. [ABSTRACT FROM AUTHOR]

The industrialization of bromine-mediated natural gas upgrading is contingent on the ability to fully recycle hydrogen bromide (HBr), which is the end form of the halogen after the activation and coupling of the alkanes. Europium oxybromide (EuOBr) is introduced as a unique catalytic material to close the bromine loop via HBr oxidation, permitting low-temperature operation and long lifetimes with a stoichiometric feed (O2:HBr=0.25)-conditions at which any catalyst reported to date severely deactivates because of excessive bromination. Besides, EuOBr exhibits unparalleled selectivity to methyl bromide in methane oxybromination, which is an alternative route for bromine looping. This novel active phase is finely dispersed on appropriate carriers and scaled up to technical extrudates, enhancing the utilization of the europium phase while preserving the performance. This catalytic system paves the way for sustainable valorization of stranded natural gas via bromine chemistry. [ABSTRACT FROM AUTHOR]

Ligand-modified palladium nanoparticles deposited on a carbon carrier efficiently catalyze the direct synthesis of H2O2 and the unique performance is due to their hybrid nanostructure. Catalytic testing demonstrated that the selectivity increases with the HHDMA ligand content from 10 % for naked nanoparticles up to 80 %, rivalling that obtained with state-of-the-art bimetallic catalysts (HHDMA=C20H46NO5P). Furthermore, it remains stable over five consecutive reaction runs owing to the high resistance towards leaching of the organic moiety, arising from its bond with the metal surface. As rationalized by density functional theory, this behavior is attributed to the adsorption mode of the reaction intermediates on the metal surface. Whereas they lie flat in the absence of the organic shell, their electrostatic interaction with the ligand result in a unique vertical configuration which prevents further dissociation and over-hydrogenation. These findings demonstrate the importance of understanding substrate-ligand interactions in capped nanoparticles to develop smart catalysts for the sustainable manufacture of hydrogen peroxide. [ABSTRACT FROM AUTHOR]

A catalytic process is demonstrated for the selective conversion of methane into carbon monoxide via oxychlorination chemistry. The process involves addition of HCl to a CH4-O2 feed to facilitate C−H bond activation under mild conditions, leading to the formation of chloromethanes, CH3Cl and CH2Cl2. The latter are oxidized in situ over the same catalyst, yielding CO and recycling HCl. A material exhibiting chlorine evolution by HCl oxidation, high activity to oxidize chloromethanes into CO, and no ability to oxidize CO, is therefore essential to accomplish this target. Following these design criteria, vanadyl pyrophosphate (VPO) was identified as an outstanding catalyst, exhibiting a CO yield up to approximately 35 % at 96 % selectivity and stable behavior. These findings constitute a basis for the development of a process enabling the on-site valorization of stranded natural-gas reserves using CO as a highly versatile platform molecule. [ABSTRACT FROM AUTHOR]

Optimal amounts of CO2 are added to syngas to boost the methanol synthesis rate on Cu-ZnO-Al2O3 in the industrial process. The reason for CO2 promotion is not sufficiently understood at the particle level due to the catalyst complexity and the high demands of characterization under true reaction conditions. Herein, we applied operando synchrotron X-ray powder diffraction and modulated-excitation infrared spectroscopy on a commercial catalyst to gain insights into its morphology and surface chemistry. These studies unveiled that Cu and ZnO agglomerate and ZnO particles flatten under CO/H2 and/or CO2/H2. Under the optimal CO/CO2/H2 mixture, sintering is prevented and ZnO crystals adopt an elongated shape due to the minimal presence of the H2O byproduct, enhancing the water-gas shift activity and thus the methanol production. Our results provide a rationale to the CO2 promotion emphasizing the importance of advanced analytical methods to establish structure-performance relations in heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Methanol synthesis by CO2 hydrogenation is attractive in view of avoiding the environmental implications associated with the production of the traditional syngas feedstock and mitigating global warming. However, there still is a lack of efficient catalysts for such alternative processes. Herein, we unveil the high activity, 100 % selectivity, and remarkable stability for 1000 h on stream of In2O3 supported on ZrO2 under industrially relevant conditions. This strongly contrasts to the benchmark Cu-ZnO-Al2O3 catalyst, which is unselective and experiences rapid deactivation. In-depth characterization of the In2O3-based materials points towards a mechanism rooted in the creation and annihilation of oxygen vacancies as active sites, whose amount can be modulated in situ by co-feeding CO and boosted through electronic interactions with the zirconia carrier. These results constitute a promising basis for the design of a prospective technology for sustainable methanol production. [ABSTRACT FROM AUTHOR]

Ceria catalyzes the one-step production of the vinyl chloride monomer (VCM) from ethylene with a high yield because of its bifunctional character: redox centers oxychlorinate ethylene to ethylene dichloride (EDC), which is subsequently dehydrochlorinated to VCM over strong acid sites generated in situ. Nanocrystalline CeO2 and CeO2-ZrO2 lead to a VCM yield of 25 % in a single pass, outperforming the best reported systems and reaching industrially attractive levels. The use of CeO2 intensifies the current two-step process within PVC production encompassing CuCl2-catalyzed oxychlorination and thermal cracking. In addition, ceria-based materials offer stability advantages with respect to the archetypical CuCl2-based catalysts. [ABSTRACT FROM AUTHOR]

Wir beschreiben die Herstellung und das Hydrierungsverhalten eines Einzelatom ‐ Palladiumkatalysators, geschaffen durch die Verankerung von Pd ‐ Atomen in den Mesoporen eines graphitischen Kohlenstoffnitridpolymers. Die Analyse des Materials bestätigt die atomare Dispersion der Palladium ‐ Phase über die komplette Probe. Gegenüber nanopartikelbasierten Vergleichskatalysatoren zeigte sich die hohe Aktivität und Selektivität deutlich bei Anwendung in der kontinuierlichen Drei ‐ Phasen ‐ Hydrierung von Alkinen und Nitroarenen in einem Durchflussreaktor. Dichtefunktionalrechnungen ermöglichten die Erarbeitung fundamentaler Erkenntnisse betreffend Materialstruktur und erlaubten, die hohe katalytische Aktivität und Selektivität auf die einfache Wasserstoffaktivierung und Kohlenwasserstoffadsorption auf den atomar verteilten Pd ‐ Strukturen zurückzuführen. Ein (geschütztes) Atom genügt: Die einzigartige Porenstruktur von Kohlenstoffnitriden ermöglicht die stabile Einlagerung isolierter Palladiumatome. Dieser heterogene „Single ‐ site”︁ ‐ Katalysator für selektive Hydrierungen übertrifft die modifizierten Palladium ‐ Nanopartikel, welche den derzeitigen Stand der Technik darstellen. [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]

Without techniques sensitive to complex pore architectures, synthetic efforts to enhance molecular transport in zeolite and other porous materials through hierarchical structuring lack descriptors for their rational design. The power of positron annihilation lifetime spectroscopy (PALS) to characterize the pore connectivity in hierarchical MFI zeolites is demonstrated, establishing a direct link with the enhanced catalyst lifetime in the conversion of methanol to valuable hydrocarbons. The unique ability to capture subtleties of the hierarchical structure originates from the dynamic nature of the ortho-positronium response to the pore network. The findings reveal the strong dependence on the way in which the hierarchical zeolites are manufactured, having direct implications for the practical realization of these advanced catalysts. [ABSTRACT FROM AUTHOR]

The determination of structure-performance relationships of ceria in heterogeneous reactions is enabled by the control of the crystal shape and morphology. Whereas the (100) surface, predominantly exposed in nanocubes, is optimal for CO oxidation, the (111) surface, prevalent in conventional polyhedral CeO2 particles, dominates in C2H2 hydrogenation. This result is attributed to the different oxygen vacancy chemistry on these facets. In contrast to oxidations, hydrogenations on CeO2 are favored over low-vacancy surfaces owing to the key role of oxygen on the stabilization of reactive intermediates. The catalytic behavior after ageing at high temperature confirms the inverse face sensitivity of the two reaction families. [ABSTRACT FROM AUTHOR]

Rutile TiO2 is a heavily investigated oxide with, to date, scarce applications in industrial catalysis. The inactivity of this material in oxidations has been related to its inability to dissociate molecular oxygen. Herein we show how rutile catalyzes the oxidation of HBr to Br2 through defect states that are introduced during the reaction. The identification of active, stable, and abundant materials for bromine production is key to the future implementation of Br2-mediated alkane functionalization processes. The catalytic properties of TiO2 are discussed in comparison to expensive rutile-type oxides, such as RuO2 and IrO2, on the basis of surface characterization and molecular modeling. [ABSTRACT FROM AUTHOR]

The article discusses the unique stability of delafossite copper chromium oxide (CuCrO2) during oxidation and chlorination. It presents a novel CuCrO2-cerium oxide (CeO2 composite for hydrogen chloride (HCl) oxidation to build on the result with fourfold activity. It states that in an equimolar mixture of copper oxide (Cu2O), single-phase cuprous delafossites were synthesized at 1273-1423 Kelvin (K) for 30 hours.

Innentitelbild: Quantification of Redox Sites during Catalytic Propane Oxychlorination by Operando EPR Spectroscopy (Angew. Keywords: alkane activation; heterogeneous catalysis; operando EPR spectroscopy; propane oxychlorination; reaction mechanism EN alkane activation heterogeneous catalysis operando EPR spectroscopy propane oxychlorination reaction mechanism 3354 3354 1 02/10/21 20210215 NES 210215 B Operando-EPR wird heiß b Im Forschungsartikel auf S. 3640 demonstrieren Guido Zichittella, Yevhen Polyhach, Javier Pérez-Ramírez et al. die Operando-EPR-Spektroskopie als zentrale Technik zur Bestimmung des Oxidationszustands von CrPO SB 4 sb - und EuOCl-Katalysatoren während der katalytischen Hochtemperatur-Oxychlorierung von Propan. Alkane activation, heterogeneous catalysis, operando EPR spectroscopy, propane oxychlorination, reaction mechanism. [Extracted from the article]

Operando‐Spektroskopietechniken können zwischen Oberflächen‐ und Gasphasen‐Prozessen bei der Alkan‐Oxyhalogenierung unterscheiden. J. Pérez‐Ramírez et al. klären in ihrer Zuschrift auf S. 5935 ff. die mechanistischen Ursprünge des Halogeneffekts auf, der die Katalyse steuert. Der selektive Umsatz von Alkanen zu Olefinen wird durch oberflächenbeschränktes Chlor angetrieben. Im Bild entspricht die Fledermauskolonie dem unselektiven Radikalkettenmechanismus in der Gasphase im Fall von Brom. Ein Engel betrachtet die Selektivitätskontrolle auf der Erde. [ABSTRACT FROM AUTHOR]

Einzelne Goldatome auf stickstoffdotiertem Kohlenstoff werden in der Zuschrift von J. Pérez‐Ramírez, N. López et al. auf S. 514 als Heterogenkatalysatoren getestet. Das Ergebnis fasst das von van Goghs "Sternennacht über der Rhone" inspirierte Titelbild zusammen: Goldatome mit maßgeschneiderten Oxidationsstufen und Koordinationssphären (Sterne) und unterschiedlichen spektroskopischen Signaturen (Reflexionen auf dem Wasser) zeigen ein Vulkan‐förmiges Leistungsverhalten bei der Hydrierung funktionalisierter Alkine (Verlauf des Ufers). Das Paar im Vordergrund versinnbildlicht Experimente und Theorie, die bei der Katalysatorentwicklung Hand in Hand gehen sollten. [ABSTRACT FROM AUTHOR]

Die Produktion leichter Olefine aus Ethan und Propan durch Oxychlorierung mit EuOCl ist das Thema der Zuschrift auf S. 13858 von J. Pérez‐Ramírez et al. Das beschriebene System verfügt über hohe Aktivität, Selektivität und Stabilität. Die mythologische Prinzessin Europa, die Zeus in seiner Verkörperung als weißer Stier aus Asien in die hellenische Welt entführte, ist namensgebend für den Erdteil wie für das zentrale Element dieser Studie. [ABSTRACT FROM AUTHOR]

Aufgestanden für die Selektivität! In ihrer Zuschrift auf S. 1801 ff. zeigen Pérez‐Ramírez et al. die hervorragende Selektivität von Liganden‐modifizierten Pd‐Nanopartikeln bei der direkten H2O2‐Synthese. Die Hybridstruktur macht die Absorption des OOH‐Intermediats auf der Oberfläche möglich und verhindert ungewünschte Dissoziations‐ und Überhydrierungspfade. Durch elektrostatische Wechselwirkungen, dargestellt von den haltenden Fäden der Pinocchio‐Marionette, mit dem Liganden wird die Konfiguration stabilisiert. [ABSTRACT FROM AUTHOR]

Riesige Erdgasvorkommen, die andernfalls abgefackelt würden, können potenziell zur Herstellung von Chemikalien und Treibstoffen dienen. In ihrer Zuschrift auf S. 15848 ff. stellen J. Pérez ‐ Ramírez und Mitarbeiter einen katalytischen Oxychlorierungsprozess vor, der Methan in den vielseitigen chemischen Grundbaustein Kohlenmonoxid umwandelt. Vanadylpyrophosphat als Katalysator liefert eine stete Kohlenmonoxidausbeute um 35 % bei 96 % Selektivität. [ABSTRACT FROM AUTHOR]

Zum Tango gehören immer zwei Die Herstellung von Methanol als Energieträger und Plattformchemikalie durch CO2 ‐ Hydrierung ist unter Nachhaltigkeitsaspekten von großer Bedeutung, allerdings werden hierzu besonders effiziente Katalysatoren benötigt. In der Zuschrift auf S. 6369 ff. zeigen J. Pérez ‐ Ramírez et al., dass synergistische Wechselwirkungen zwischen In2O3 und einem ZrO2 ‐ Träger ein stabiles Material ergeben, das die Synthese von Methanol in hohen Raum ‐ Zeit ‐ Ausbeuten und mit einer Selektivität von fast 100 % ermöglicht. [ABSTRACT FROM AUTHOR]

Viele Vögel bauen Nester …︁ …︁, um ihre Eier auszubrüten und ihre Jungen in geschützter Umgebung großzuziehen. In ihrer Zuschrift auf S. 11417 ff. verwenden J. Pérez ‐ Ramírez, N. López et al. ein “Nestbau ‐ Konzept” für die Einlagerung isolierter Palladiumatome in den Poren von graphitischem Kohlenstoffnitrid. Dies führt zu einem hervorragenden heterogenen “Single ‐ Site” ‐ Katalysator für Hydrierungsreaktionen (Titelbildkonzept: Amalia Gallardo, Illustration: Marcel Reich). [ABSTRACT FROM AUTHOR]

Struktur ‐ Leistungs ‐ Beziehungen für Ceroxid in heterogenen Reaktionen werden von J. Pérez ‐ Ramírez, A. Trovarelli et al. in ihrer Zuschrift auf S. 12265 ff. vorgestellt. Die in herkömmlichen polyedrischen CeO2 ‐ Partikeln übliche (111) ‐ Oberfläche ist besser für Hydrierungen, die von Nanowürfeln präsentierte (100) ‐ Oberfläche besser für Oxidationen. Bildgestaltung: Amalia Gallardo (ArteLi) und Marcel Reich. [ABSTRACT FROM AUTHOR]

N. López, J. Pérez ‐ Ramírez und Mitarbeiter zeigen auf S. 8772 ff., wie HBr ‐ Dotierungen auf der Oberfläche von Rutil ‐ TiO2 Verunreinigungsniveaus erzeugen, die mit Reaktanten passender Energie Elektronen austauschen. Der katalytisch inerte Halbleiter wird dadurch zum aktiven Katalysator. [ABSTRACT FROM AUTHOR]

The cover page for the September 2013 issue of the journal "Angewandte Chemie" is presented.