CatLab – Catalysis Laboratory
CatLab Highlight Lectures 02.11.2022
10:15 | Prof. Katharina Krischer
12:30 | Prof. Joost Wintterlin
02.11.2022 |10:15 am CET |BESSY Lecture Hall & Online
Prof. Dr. Katharina Krischer, Chemical physics far from equilibrium, Technische Universität München.
Nonlinearities in Action: Cooperative Phenomena and Collective Dynamics in Electrochemistry
Moderated by Prof. Robert Schlögl (Fritz-Haber-Institut)
In this talk, I will discuss recent examples from electrochemistry in which the system’s behavior is ‘more than the sum of its parts’ and nonlinear interactions generate complex forms of organization. Thereby, I will highlight general conditions that generate certain types of cooperative phenomena. Experimental examples range from electrocatalytic reactions, to the electrooxidation of photoelectrodes. The patterns forming can be understood in the framework of ‘many particle models’ with nonlinear and nonlocal interaction between the particles, as they are often found in electrochemical systems.
Biography
Prof. Dr. Katharina Krischer is the first female professor in the Faculty of Physics at the TU Munich. Born in Bensheim and raised in Berlin, she studied chemistry at the Free University of Berlin until her intermediate diploma. She then moved to Ludwig Maximilian University in Munich, where she graduated as a chemist in 1987.
CatLab Highlight Lecture by Prof. Dr. Joost Wintterlin
02.11.2022 | 12.30 am CET | BESSY Lecture Hall & Online
Prof. Dr. Joost Wintterlin
Department Chemie and CeNS
Ludwig-Maximilians-Universität München
Towards STM of catalytic reactions
Moderated by Prof. Robert Schlögl (Fritz-Haber-Institut)
Scanning tunneling microscopy (STM) regularly offers atomic resolution, can work at high pressures and only interacts weakly with matter - seemingly perfect conditions for gaining access to the microscopic processes on a catalyst surface. On the other hand, the number of examples in which working catalysts have actually been imaged with the STM has remained small. This contradiction is due not so much to fundamental problems as to numerous practical, experimental difficulties. In this talk, I present the results of our efforts to resolve some of these difficulties. In one project, a combination of a high-pressure STM and a special gas chromatograph was developed. With this system, the co-catalyzed Fischer-Tropsch synthesis, an industrial process for the production of liquid hydrocarbons from mixtures of CO and H2 (synthesis gas), was investigated. Under reaction conditions, Co single crystals serving as model catalysts were imaged with atomic resolution and the catalytic turnover frequency was measured under the same conditions. The correlations in these data provide clear indications of the active sites of this reaction. In a second project, high-speed STM technique was further developed in order to investigate dynamic processes in the adsorption layer. Surface diffusion, which determines collision rates between reacting particles on a catalyst surface, was studied. It is shown that diffusion can be extremely fast even at the high coverages typically present on an operating catalyst. A novel 2D lattice diffusion mechanism is proposed.
Biography
Prof. Dr. Joost Wintterlin has been Professor of Chemistry at the Ludwig Maximilian University since 2002. He studied chemistry at the LMU University in Munich. In 1989 he completed his doctorate at the Fritz Haber Institute. He moved to New York to continue his research as a postdoc at the IBM T.J Watson Research Center.