@misc{PlattfautSuckowKlepeletal., author = {Plattfaut, Julia and Suckow, Matthias and Klepel, Olaf and Erlitz, Marcel and Arellano-Garc{\´i}a, Harvey}, title = {Modellierung und Simulation der templatgest{\"u}tzten Synthese von por{\"o}sen Kohlenstoffger{\"u}sten mittels COMSOL Multiphysics}, series = {Chemie Ingenieur Technik}, volume = {96(2024)}, journal = {Chemie Ingenieur Technik}, number = {3}, issn = {1522-2640}, doi = {10.1002/cite.202300014}, pages = {318 -- 328}, abstract = {Mithilfe einer templatgest{\"u}tzten Synthese wurden por{\"o}se Kohlenstoffger{\"u}ste unter Verwendung von Silicagel als Templat hergestellt. Die chemische Gasphaseninfiltration (CVI) wurde hierbei als Synthese verwendet. Unter Variation verschiedener Reaktionsparameter zur Optimierung der Kohlenstoffabscheidung wurde dieser Prozess mathematisch modelliert and simuliert. Dabei konnten die experimentellen Ergebnisse gut mit den Modellen nachgebildet werden. Die zus{\"a}tzliche Beschreibung der laminaren Str{\"o}mung verbessert die {\"U}bereinstimmung deutlich.}, language = {de} } @misc{GonzalezCastanoMoralesNavarrodeMigueletal., author = {Gonzalez-Cast{\~a}no, Miriam and Morales, Carlos and Navarro de Miguel, Juan Carlos and Boelte, Jens-H. and Klepel, Olaf and Flege, Jan Ingo and Arellano-Garc{\´i}a, Harvey}, title = {Are Ni/ and Ni5Fe1/biochar catalysts suitable for synthetic natural gas production? A comparison with γ-Al2O3 supported catalysts}, series = {Green Energy \& Environment}, volume = {8}, journal = {Green Energy \& Environment}, number = {3}, issn = {2468-0257}, doi = {10.1016/j.gee.2021.05.007}, pages = {744 -- 756}, abstract = {Among challenges implicit in the transition to the post-fossil fuel energetic model, the finite amount of resources available for the technological implementation of CO2 revalorizing processes arises as a central issue. The development of fully renewable catalytic systems with easier metal recovery strategies would promote the viability and sustainability of synthetic natural gas production circular routes. Taking Ni and NiFe catalysts supported over γ-Al2O3 oxide as reference materials, this work evaluates the potentiality of Ni and NiFe supported biochar catalysts for CO2 methanation. The development of competitive biochar catalysts was found dependent on the creation of basic sites on the catalyst surface. Displaying lower Turn Over Frequencies than Ni/Al catalyst, the absence of basic sites achieved over Ni/C catalyst was related to the depleted catalyst performances. For NiFe catalysts, analogous Ni5Fe1 alloys were constituted over both alumina and biochar supports. The highest specific activity of the catalyst series, exhibited by the NiFe/C catalyst, was related to the development of surface basic sites along with weaker NiFe-C interactions, which resulted in increased Ni0:NiO surface populations under reaction conditions. In summary, the present work establishes biochar supports as a competitive material to consider within the future low-carbon energetic panorama.}, language = {en} } @misc{BoelteUtgenanntSchmidtetal., author = {B{\"o}lte, Jens-Henning and Utgenannt, Stephan and Schmidt, Max and Klepel, Olaf and Bron, Michael and Rokicińska, Anna and Jarczewski, Sebastian and Kuśtrowski, Piotr}, title = {S-doped and N+S-co-doped carbon catalysts in redox reactions}, series = {Microporous and mesoporous materials}, volume = {407}, journal = {Microporous and mesoporous materials}, publisher = {Elsevier BV}, address = {Amsterdam}, issn = {1873-3093}, doi = {10.1016/j.micromeso.2026.114129}, pages = {1 -- 11}, abstract = {In this contribution, the effects of heteroatom doping of porous carbon materials with S and N on their ability to catalyze redox-reactions involving the activation of molecular oxygen were investigated. For this purpose, a library of in total 54 undoped, S-doped and N + S-co-doped porous carbons was obtained via a template-based synthesis procedure using mesoporous silica gel as the template. To understand the influence of S on the properties of the doped carbons three different S-containing precursors, namely dimethyl sulfoxide (DMSO), p-toluene sulfonic acid and thiophene, were used. In order to investigate possible synergistic effects of S- and N-co-doping, urea was employed as the sole N-containing precursor. The obtained carbon catalysts were characterized by selected methods such as N2-physisorption at 77 K, X-ray diffraction (XRD), Raman spectroscopy, elemental analysis and X-ray photoelectron spectroscopy (XPS). Each carbon catalyst was tested in the oxidation of sulfurous acid (OSA) to sulfuric acid, the electrochemical oxygen reduction (ORR) and the oxidative dehydrogenation (ODH) of ethylbenzene. Owing to the similar textural and structural properties achieved through template-based synthesis of the carbon catalyst library, the results of the catalytic redox-reactions could directly be related to the respective heteroatom dopant. The observed trends indicate that in these redox-reactions S-species behave somewhat similar to O-species bound on the carbon surface. Furthermore, it can be shown that N + S co-doping rather combines the positive and negative effects of the individual dopants on the activity, than creating a synergistic effect that surpasses the individual contribution.}, language = {en} }