Stephan Schunk

Dr. Stephan Schunk

orcid

Research Focus & Metrics

Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 January 2020 in ChemCatChem
Verified
Journal Article
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KWKnut Wittich
Knut Wittich
MKMichael Krämer
Michael Krämer
NBNils Bottke
Nils Bottke
SSStephan Schunk
Stephan Schunk
Catalytic dry reforming under industrially relevant conditions of high pressures and high temperatures poses severe challenges towards catalyst materials and process engineering. The demanding conditions under which the reaction is performed lead to a coupling of reactions occurring in the gas phase and reactions which are catalyzed by the material employed as catalyst. A profound analysis of the mechanisms occurring in gas phase and resulting products from gas phase reactions is key to understanding part of the challenges that any catalyst material, irrespective of its nature, will have to cope with. The deposition of coke on an active catalyst is as well one of the most limiting factors for catalyst lifetime and catalyst activity in dry reforming. Therefore, an understanding of the thermodynamics behind coke formation and an intricate description of the mechanisms driving the evolution of coke is a vital piece of the picture. Acid‐base properties of the catalyst material and the role and nature of the active metal do also need to be considered. A large part of the review deals with mechanisms which are relevant for coke gasification and insights into materials properties, which are relevant to allow for reaction pathways along these lines. The review article focusses on research results which have been achieved using model systems – typically the analysis of model systems is a more rewarding exercise compared to fully formulated industrial catalyst systems, as here more elucidating structure‐property relationships can be drawn. Additionally the article discusses dry methane reforming in the context of alternative syngas generation technologies and attempts to create an application perspective for the reader in the context of a sustainable approach towards carbon capture and storage.

6 May 2020 in Catalysts
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Journal Article
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SHSchirin Hanf
Schirin Hanf
LRLuis Alvarado Rupflin
Luis Alvarado Rupflin
Roger GläserRoger Gläser
Roger Gläser
SSStephan Schunk
Stephan Schunk
The hydroformylation of olefins is one of the most important homogeneously catalyzed processes in industry to produce bulk chemicals. Despite the high catalytic activities and selectivity’s using rhodium-based homogeneous hydroformylation catalysts, catalyst recovery and recycling from the reaction mixture remain a challenging topic on a process level. Therefore, technical solutions involving alternate approaches with heterogeneous catalysts for the conversion of olefins into aldehydes have been considered and research activities have addressed the synthesis and development of heterogeneous rhodium-based hydroformylation catalysts. Different strategies were pursued by different groups of authors, such as the deposition of molecular rhodium complexes, metallic rhodium nanoparticles and single-atom catalysts on a solid support as well as rhodium complexes present in supported liquids. An overview of the recent developments made in the area of the heterogenization of homogeneous rhodium catalysts and their application in the hydroformylation of short-chain olefins is given. A special focus is laid on the mechanistic understanding of the heterogeneously catalyzed reactions at a molecular level in order to provide a guide for the future design of rhodium-based heterogeneous hydroformylation catalysts.

10 March 2021 in ChemCatChem
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Journal Article
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CWChristoph Wulf
Christoph Wulf
MBMatthias Beller
Matthias Beller
TBThomas Boenisch
Thomas Boenisch
ODOlaf Deutschmann
Olaf Deutschmann
SHSchirin Hanf
Schirin Hanf
DLDavid Linke
David Linke
Modern research methods produce large amounts of scientifically valuable data. Tools to process and analyze such data have advanced rapidly. Yet, access to large amounts of high‐quality data remains limited in many fields, including catalysis research. Implementing the concept of FAIR data (Findable, Accessible, Interoperable, Reusable) in the catalysis community would improve this situation dramatically. The German NFDI initiative (National Research Data Infrastructure) aims to create a unique research data infrastructure covering all scientific disciplines. One of the consortia, NFDI4Cat, proposes a concept that serves all aspects and fields of catalysis research. We present a perspective on the challenging path ahead. Starting out from the current state, research needs are identified. A vision for a integrating all research data along the catalysis value chain, from molecule to chemical process, is developed. Respective core development topics are discussed, including ontologies, metadata, required infrastructure, IP, and the embedding into research community. This Concept paper aims to inspire not only researchers in the catalysis field, but to spark similar efforts also in other disciplines and on an international level.

21 April 2017 in ACS Catalysis
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Journal Article
Closed access
LRLuis Alvarado Rupflin
Luis Alvarado Rupflin
JMJaroslaw Mormul
Jaroslaw Mormul
MLMichael Lejkowski
Michael Lejkowski
STSven Titlbach
Sven Titlbach
RPRainer Papp
Rainer Papp
SSStephan Schunk
Stephan Schunk


16 April 2025 in JACS Au
Verified
Journal Article
Open access
SKSungmin Kim
Sungmin Kim
BYBoda Yang
Boda Yang
Oliver GutierrezOliver Gutierrez
Oliver Gutierrez
WZWei Zhang
Wei Zhang
Carlos Lizandara PueyoCarlos Lizandara Pueyo
Carlos Lizandara Pueyo
JLJohannes A. Lercher
Johannes A. Lercher
Ru/C-catalyzed polyethylene (PE) and hydrocarbon hydrogenolysis under quasi-supercritical fluid of isopentane was kinetically and mechanistically investigated. PE hydrogenolysis with C-C and C-H cleavage showed zeroth order, suggesting strong adsorption of hydrocarbons. PE yielded broad product distribution of heavy (C21-40) and diesel-range (C11-20) hydrocarbons in the primary step of hydrogenolysis due to stochastic C-C cleavage over Ru surface. Catalytic hydrogenolysis of n-hexadecane, squalane, and light hydrocarbons such as n-pentane, iso-pentane, and n-hexane further described C-C cleavage reactivity between primary and secondary carbons, i.e., 1C-2C and 2C-2C, which has an order of magnitude higher hydrogenolysis rate than that involving a tertiary carbon. The PE saturated Ru surface and lower C-C cleavage reactivity of tertiary carbon in iso-pentane, therefore, imited sovlent conversion during hydrogenolysis, whereas leading to selective PE conversion. Using hexadecane, we observed comparable hydrogenolysis rates between H2 and D2 (k H /k D ∼ 1), indicating the kinetically relevant step of C-C cleavage with facilitating C-H cleavage and rehydrogenation. However, the normal kinetic isotope effect between hexadecane and deuterated hexadecane (k C16H34 /k C16D34 ∼ 5) revealed that the dehydrogenation, i.e., C-H cleavage, can be kinetically involved in the hydrogenolysis kinetic. By considering the 8-fold lower H-D exchange rate with deuterated hexadecane compared to n-hexadecane, the lower rate for hydrogenolysis and H-D exchange with deuterated hexadecane can be attributed to the C-D bond dissociation energy being 3 kJ/mol higher than that of the C-H bond. Increasing H2 pressure favors internal C-C bond cleavage over terminal one. This minimizes the formation of lower hydrocarbons, particularly methane. However, the increase in H2 pressure increases the coverage of adsorbed hydrogen on the Ru particles due to competitive adsorption of H2 and polyethylene, which, in turn, reduces the polyethylene conversion rates.