Dr. Oliver Y. Gutiérrez

Group Leader

Catalysis Research Center and Chemistry Department

Technische Universität München

Lichtenbergstraße 4

85748 Garching, Germany

Biographical Note

Oliver Y. Gutiérrez is a senior scientist and group leader at the chair of Technical Chemistry II at the Technische Universität München. He received his doctorate in 2009 from the UNAM (the National University of Mexico), where he was awarded the “Antonio Caso” medal for graduating at the top of his class. In the same year, he received the Alexander-von-Humboldt fellowship and moved to Germany for a postdoctoral position at TU Munich with Prof. Johannes Lercher. In 2011 he was appointed senior scientist at the same chair creating a research group focused on catalysts for industrial applications. His research on fundamental aspects of heterogeneous catalysis combines in situ characterization of catalytic materials with rigorous kinetic analysis and synthesis of catalysts. His current research topics cover mainly sulfide and metal catalysts for hydrotreating and for alternative low-temperature processes.

Selected Awards

Alexander von Humboldt fellowship
“Alfonso Caso” award by the UNAM
Level 1 Researcher by the National Research System of Mexico (SNI) since 2010

Research

The aim of our work is to bridge from molecular description of catalytic reactions to the design of novel catalysts and catalytic processes. Our work focuses, therefore, on the fundamental aspects of catalyzed reactions. Topics of our research have evolved around hydrotreatment and production of energy carriers at mild conditions. Therefore, the studied materials mainly include bulk or supported transition metal sulfides, and supported metal nanoparticles. Rigorous kinetics and advanced characterization methods (in situ IR, Raman, and X-ray absorption spectroscopy as well as X-ray diffraction, temperature programmed reactions, etc.) are used to understand the properties of these materials in stages of preparation and during/after sorption and catalysis. Catalytic target reactions include hydrodefunctionalization (S-, N-, and O-removal), hydrogenation of aromatic compounds, synthesis of thiols, and hydrogen generation.

Hydrotreating on sulfide catalysts

Transition metal sulfides (MoS₂, WS₂) are one of the most relevant kinds of catalysts in industry. In hydrotreatment, they are used for the removal of heteroatoms (S, N, O, metals), and hydrogenation of oil feedstocks. The most studied functionality of MoS₂- and WS₂-based catalysts is hydrodesulfurization (HDS) because sulfur is the most abundant impurity in fossil oil feedstock. However, hydrodenitrogenation (HDN) is increasingly important because N-species may be unreactive (due to strong adsorption) and hinder other functionalities like HDS on sulfide catalysts.
In this research topic, we aim to understand the mechanisms and active sites on MoS2 that allow efficient N-, and S-removal from aromatic compounds. We have analyzed different steps (e.g., hydrogenation, C-N, and C-S bond cleavage) of this catalytic chemistry on Ni-MoS2 supported on alumina. The results, based on detailed characterization of the sulfides, including active site titration, and advance spectroscopy, allowed to extent the project towards understanding hydrodenitrogenation on unsupported multimetallic (Ni-Mo-W) catalysts. These systems consist of mixtures of sulfides of different compositions and crystallographic phases, with intrinsically different activities and selectivity. This current research seeks to define the contribution of all phases and the synergies among them.

Synthesis of methanethiol on sulfide catalysts

Methanethiol (CH₃SH) is an important raw material in chemical industry mainly used for the production of methionine. The state of the art process for the synthesis of methanethiol is methanol thiolation. However, it is of interest to develop novel synthesis routes and catalysts with improved activity and selectivity. The activities of our group in this field started with the development of syngas-based reaction routes towards methanethiol. Currently, new catalysts are being developed for the state-of-the-art process.
The research aims to answer the question as to how alkali metals influence sulfide catalysts in order to provide high selectivity towards thiols from diverse C1 sources. This work shed light into an aspect of catalysis on sulfides, synthesis of chemical commodities, which is far from understood.

Hydrogenation of aromatic compounds on sulfide catalysts

Another very important aspect of hydrotreatment on sulfide catalysts is hydrogenation of aromatic compounds. The attention to this topic is foreseen to increase because of the increasing content of polyaromatics in fossil fuels, which need to be converted, and the potential use of naphtenates/aromatics as hydrogen carriers.
Taking Ni-promoted MoS₂ as target system, and the hydrogenation of phenanthrene as target reaction, the location and effect of the promoter on the hydrogenation functionality of MoS₂ has been studied with rigorous kinetics and advance spectroscopy. The main questions in this research include H₂ activation at the sulfide surface and addition to the aromatic molecule, as well as the identity of the sites that perform these steps.

Production of energy carriers at low temperature

The energy challenge of our days is not limited to the utilization of fossil- and biomass- derived oil but also to the generation, storage, and utilization of energy carriers, especially hydrogen. Thus we have also developed research in the area of catalysis at mild conditions driven by light or electrical potential. In the field of photocatalysis, hydrogen generation via overall water splitting and reforming has been recently studied. Noble metal particles, supported on semiconductor materials have been tested in liquid phase reactions with low concentrations of methanol, polyols or sugars. On the other hand, the metal clusters at the surface of the semiconductor are being modified in situ in order to tune the rates of water splitting and water-gas shift reaction. Thus we contribute to the understanding of light-driven reforming in aqueous phase and to developing new systems able to produce hydrogen at mild conditions.
Our research on electrocatalysis, is focused on investigating the room temperature hydrogenation of model compounds with noble metal catalysts supported on carbon. The effect of reaction parameters on the hydrogenation rates and product distributions are being explored. Furthermore, comparisons of thermal catalysis and electrocatalysis are proving to be a valuable tool for the understanding of reaction mechanisms at macroscopic and molecular levels.

Hydrodeoxygenation of carboxylic acids

Increasing contributions of biomass-derived oils to refinery feedstocks for fuel production pose new challenges for state-of-the-art sulfide hydrotreating catalysts. These catalysts are designed for the heteroatom-removal from crude oil fractions, but have not yet been optimized for the high concentrations of triglycerides present in bio-oils. Potential catalyst deactivation, and extensive carbon- and hydrogen-losses are the most important bottlenecks for the application of existing technology in biomass conversion, which requires extensive hydrodeoxygenation (HDO).
Current investigations of HDO of carboxylic acids (as model compounds for third-generation biomass derived oil) on sulfide catalysts focus on the mechanisms behind those phenomena in order to propose strategies to suppress them. As an alternative to sulfides, transition metal phosphides are interesting because they are intrinsically more active and more poison tolerant than most base or noble metals. Thus, another aspect of this research is to investigate the activity of diverse transition metal phosphides in the conversion of carboxylic acids.