Dr. Ricardo Bermejo de Val

Group Leader

Catalysis Research Center and Chemistry Department

Technische Universität München

Lichtenbergstraße 4

85748 Garching, Germany

 

Biographical Note

 

Ricardo Bermejo de Val is currently a senior scientist and group leader at the chair of Technical Chemistry II at the Technische Universität München. He earned his B.Sc./M.S in 2010 in Chemical Engineering from the University of Valencia, where he was awarded the “Premio Extraordinario Fin de Carrera” for graduating at the top of his class. He received his Ph.D. in Chemical Engineering from California Institute of Technology in 2014, working under the supervision of Mark E. Davis. His thesis work involved mechanistic studies in the isomerization and epimerization of glucose with Lewis acid zeolites, focusing in the zeolite synthesis of framework and non-framework Lewis acid metals. He then moved to the Technical University of Munich to do postdoctoral research in methanol thiolation with transition metals in the group of Professor Johannes A. Lercher. In 2016 he received the Alexander-von-Humboldt fellowship and was appointed senior scientist at the same chair, creating a research group focused on heterogeneous catalysis with Lewis acids. His current research is on mechanistic studies on heterogeneous catalysis, combining in situ characterization of catalytic materials with rigorous kinetic analysis and synthesis of catalysts.

Selected Avards

2016 Alexander von Humboldt fellowship

2010 “La Caixa” Graduate Fellowship

2010 Premio Extraordinario Fin de Carrera- Chemical Engineering Class Valedictorian

2009 Spanish Ministry of Education and Science Fellowship for Undergraduate Research

2008 Spanish National Research Council (SNRC) Fellowship for Undergraduate Research

 

Research

The aim of my work is to be able to design in advance the adequate chemical environment of a metal cation for a unique chemical reaction. This involves the understanding of reaction mechanisms, as well as the synthesis of a wide range of solid catalysts

Lewis-Brønsted acid pairs centers in zeolites for the activation of alkanes

Dehydrocyclodimerization is industrially applied for converting liquefied petroleum gas (mainly C3 and C4 hydrocarbons) into aromatic compounds (benzene, toluene and xylenes (BTX)) and H2. On bifunctional catalysts (e.g., Ga/H-ZSM-5) alkane dehydrogenation is the rate determining step of the dehydrocyclodimerization process. Brønsted-Lewis acid pairs formed by protonic sites in zeolites and metal cations (Zn or Ga), respectively, have shown to increase the rates of light alkane dehydrogenation. However, the state and the role of the metal cation on alkane dehydrogenation has not been discerned. Understanding these fundamental structure-activity relationships is essential for a successful catalyst development, as the maximum conversion achievable with high propene selectivity to the desired BTX products can be controlled by optimizing the Mn+/Al ratio. The aim of this work is to identify how the proximity of the Mn+ to the BAS and the location of these in the zeolite micropore are key for an efficient reaction pathway in the dehydrogenation of alkanes.

EFAl-SBAS synergy for C-C and C-H bond cleavage

Zeolites are commonly employed as solid acid catalysts in petroleum and petrochemical industry for reactions such as isomerization, alkylation and cracking. Strong Brønsted acid sites (SBAS) in zeolites, bridging OH groups (SiOHAl), are generally considered as the active sites in cracking. Mild steaming can hydrolyze a tetrahedral framework Al to form extra-framework Al (EFAlOH) in proximity to a SBAS, increasing the turnover frequency (TOF) of the SBAS. The space-occluding EFAl has shown to reduce the effective void size, increasing the interaction of the hydrocarbon via dispersion forces. Our aim is to systemically create highly active zeolite catalysts by controlled mild steaming. We would like to study the nature of these highly active BAS in proximity to EFAL. This will allow us to correlate the alkane cracking (and dehydrogenation) kinetics with the local environment of the BAS sites.

Synthesis of methanethiol on sulfide catalysts

The thiolation of alcohols is an important chemical process in the production of chemical commodities, being widely used in the production of pesticides, pharmaceuticals and petrochemicals. Alkali-promoted transition metal oxides are known to be highly active in alcohol thiolation. Although these catalysts have been used for decades in the process, the nature of its active phase is not fully understood yet. In addition, these catalysts suffer a phase transition during the reaction which leads to deactivation. The goal of this project is to get fundamental understanding of the selective thiol formation. Therefore, we are working on identifying the specific nature of the active sites, as well as those that lead to the byproduct formation. Transition metals are being used, studying the effect of the support, sulfidation procedure and promoter. The use of kinetic measurements and in situ characterization will allow us to shed light on the role of the support and the different active phases in the thiolation of alcohols.

Alkene oligomerization with nickel zeolites

The growing shale and natural gas resources provide new platform molecules for the synthesis of widely used chemical products. Small chain alkenes are formed as chemical intermiediates from these platform molecules, oligomerizing into larger linear and monobranched alkenes. Currently, alkene dimerization is catalyzed with nickel nanoparticles supported on silica-alumina, leading to nanoparticle agglomeration and its deactivation. Thus, the dispersion of Ni2+ in zeolites, compensating two negative charges in the aluminosilicate framework, can enhance the catalyst lifetime. The goal of our research is to determine the role of the Ni2+ active site and its contribution in the mechanism to form linear and branched alkenes, to be able to tune other silicoaluminates for the desired products.