39. Prof. Hans-Joachim Freund - Heterogeneous Catalysts at the Atomic Scale

Full title: Model Systems for Heterogeneous Catalysts at the Atomic Scale
Speaker: Prof. Hans-Joachim Freund (Fritz-Haber-Institut, MPG, Berlin, Germany)

00:00 - Introduction
02:23 - Catalysis at the atomic scale
11:17 - Oxide surfaces and films
16:38 - Active sites at metal-oxide interfaces
29:07 - CO2 activation on Au/MgO
33:45 - Activation of CO2 through Doping
36:59 - Adsorption and reactions in a confined space
39:26 - Confinement between SiO2 film and Ru(0001)
54:27 - Action spectroscopy using messengers
57:59 - The case study of V2O5 (0001) / Au (111)
1:02:32 - Atomic arrangement at the Fe3O4(111) surface

Q&A:
1:08:00 - Q1: The depth of the near-surface layer that determines adsorption
1:09:43 - Q2: Stability of SiO2 film and its properties
1:12:02 - Q3: Structure of the vitreous silica phase
1:14:20 - Q4: Au growth on Mo-doped CaO
1:20:44 - Q5: Physical effect of the limited space at the atomic scale
1:23:41 - Q6: Adsorption processes from Angle-Resolved Photoemission (ARPES)
1:27:11 - Q7: What can and cannot be predicted by theory (DFT)
1:28:31 - Q8: Poorly defined catalytic surfaces
1:31:27 - Q9: Advice to early stage researchers in catalysis
1:34:01 - Q10: What can electrochemists learn from the field of heterogeneous catalysis?


https://www.electrochemicalcolloquium...

#physics #chemistry #surface

Abstract:
We have created model systems for heterogeneous catalysts on the basis of thin oxide films and its modifications. This permits us to apply the toolbox of surface science for characterization and reaction studies. In the presentation I will discuss three case studies to demonstrate how those systems may be studied at the atomic scale. The first one shows how adsorption and reaction on oxide supported nanoparticle systems may be studied, exemplified by the system Co2/Au/MgO. The second one discusses a novel characterization technique, namely surface action spectroscopy, using concepts developed in gas phase studies to record vibrational spectra of extremely dilute specimen based on messenger desorption. The third case study deals with a reaction in confined space using a model system based on a thin silica film, which is only bound to a metal substrate by dispersive forces, leaving a space between the oxide film and the metal substrate. Here we study water formation from intercalated oxygen, adsorbed on the metal surface and hydrogen provided from the gas phase in operando, and deduce the details of the kinetics of the reaction in confined space in direct comparison to the equivalent open space reaction. Many of the experimental observations are interpreted on the basis of DFT calculations and kinetic models.