Department of

Inorganic Chemistry

Fritz-Haber-Institut der Max-Planck-Gesellschaft

Further information on departmental activities can be found:

Facts and figures4 group leaders

6 major research areas

17 funded cooperation projects (including 1 EU

project, 1 CoE Unicat, 1 BMBF project, 3 projects mainly

funded by industrial partners, one NSF-funded project (PIRE)

~110 publications per year

35 patents within the period 1996 - 2015

~10 Guest-Lecturers per year

Internal structure

Scientific Art Gallery

Research areas

Teaching activities

Nanostructured catalysts in C-H and CO2 activationThe current project is focused on oxidative C-H activation and oxidation of C2-C4

alkanes and alkenes for synthesis of olefins or oxygenates over oxides and metal

nanoparticles, and comprises also research activities in the oxidative coupling of

methane (OCM) over alkaline earth oxides as model catalysts. Metal-support

interactions are studied in hydrogenation of CO and CO2. The challenging

complexity of the matter requires the synthesis of well-defined catalyst precursors

including phase-pure crystalline oxides, supported metal oxide species and

stabilized metal nano-particles. In-situ spectroscopic methods are applied to

investigate catalyst synthesis and properties of catalysts in proven action.

Gold-based catalysts in CO oxidationThe discovery that gold nanoparticles (Au NPs) supported on metal oxides are

active in low-temperature CO oxidation has inspired a considerable amount of

research focused on understanding the basis of activity of Au catalysts. Various

factors -such as quantum size effects, low coordinated atoms, surface ions and the

support interaction- have been proposed as factors that influence Au activity. Our

ongoing work utilizes in-situ Near-Ambient-Pressure X-ray Photoemission

Spectroscopy (NAP-XPS) and ex-situ techniques to experimentally evidence the

activation mechanism of gold. Different strategies to activate Au were applied:

oxidation by ozone, synthesis of Au nanoparticles (Au NPs) on oxygen-free

supports (carbon and Au foil), synthesis of Au nanoparticles on transition metal

oxides by photodecomposition and precipitation methods.

Li-ion batteries and water splittingThe electrochemistry group aims to overcome the so far phenomenological

knowledge of electrochemical energy conversion and storage systems towards a

mechanistic understanding. We therefore combine classical electrochemical

experiments with analytical tools for surface- and nano science, especially X-ray

absorption spectroscopy, infrared spectroscopy and analytical transmission

electron microscopy. Within our studies on Li-ion batteries we address the charge

storage mechanism and degradation processes in electrode materials, currently

focusing on silicon. The water splitting research focuses on the degradation

mechanism of carbon with respect to their application as support for the oxygen

evolution reaction.

http://www.fhi-berlin.mpg.de

The AC Department covers teaching aspects within the

- Unicat/BIG-NSE (Unifying Concepts in Catalysis is a

Cluster of Excellence and BIG-NSE is the graduate school)

- IMPRS (International Max Planck Research School)

- Lecture Series “Modern Methods in Heterogeneous Catalysis

Research”

Preface

Charge transport in catalysisCharge transport at interfaces plays a decisive role in materials science, for

example in energy storage devices and in heterogeneously catalyzed reactions,

such as the activation of hydrocarbons. The bonding and reaction of molecules on

metal oxide surfaces is usually described by localized surface molecular models.

However, for a complete description of the catalytic working mode, macroscopic

collective electronic properties of the catalyst have to be considered as well. These

properties can control the surface charge density, surface oxidation state, surface

oxygen vacancy density, etc., and hence the formation of local active sites. The

aim of our research is: 1) to investigate the kinetics and thermodynamics of charge

transport across interfaces under reaction conditions, and 2) to understand their

relevance to catalytic activity and selectivity for the desired reaction products.

Soft X-ray photoelectron spectroscopy at electrified

solid-liquid interfacesOne of the main goals in electrochemistry is the characterization of electrode-

electrolyte interfaces under working conditions. However, the lack of surface

sensitive techniques able to monitor the electronic structure in liquid environment

hinders the understanding of electrochemical processes, which are relevant in the

energy conversion systems such as supercapacitors, Li-batteries, fuel cells and

electrolyzers. In our laboratory we aime to characterize the electronic structure of

electrified solid-liquid interfaces by means of in situ photoelectron spectroscopy

using soft (ISISS beam-line) and in the future tender (EMIL) X-ray regimens

provided by the synchrotron radiation facility (HZB/BESSY II).

Structural analysis and chemical electron microscopyWe perform structural and compositional investigations of catalyst materials using

a combination of X-ray diffraction and analytical electron microscopy techniques. In

the last couple of years, we have developed and implemented methods for real-

space and direct structural observation of catalysts under relevant catalytic

conditions. The approach can be summarized as “Chemical electron microscopy”

and means analytical electron microscopy with a strong focus on the chemical

state of the investigated materials and especially, under consideration of gas phase

induced chemical dynamics. We thus go beyond traditional high-resolution imaging

of the atomic arrangement in vacuum and move towards a description of the

relevant dynamic state of an active catalyst.

Staff scientists are regularly involved in the course programme

of the Technische Universität and Humboldt Universität in Berlin

as well as in teaching activities of the Universities of Messina

and Milano and the Dalian Institute for Chemical Physics,

Chinese Academy of Science.

Contact: Dr. S. Wrabetz; wrabetz@fhi-berlin.mpg.de October 2015

We are an interdisciplinary group between chemistry and physics working in catalysis science. Our core mission is to contribute to the functional understanding of heterogeneous catalysis.

We use the standard model of the single crystal approach as our operational base and identify conceptual additions that are necessary to make the model operational in high performance

catalysis. In this way we lay the bridges across the “gaps” in catalysis science denominated in the literature over the last two decades.

Our group is active at two locations namely in Berlin at the FHI and in Mühlheim/Ruhr at the MPI CEC (Chemical Energy Conversion). This originates from the dual function of the director

as member of the collegium at the FHI in Berlin and as founding director at the MPI CEC.

One core family of reactions of interest in our department is oxidation. We study the reaction of molecular oxygen with activated (olefins) and non-activated (small alkanes) hydrocarbons.

Another family of reactions deals with the reductive activation of CO2 and di-nitrogen. Finally, we study the generation of hydrogen through the oxidation of water to di-oxygen. In a broader

context all our projects revolve around the characterisation of the reactivity of solid interfaces. This includes also electrodes for liquid phase reactions and in batteries.

We concentrate in our work on functional understanding. This requires the controlled and reproducible synthesis of our interfaces by preferably chemical methods to include the control of real structure in the samples. Then we

perform a suite of in-situ reactivity studies of the geometric and electronic structure. We observe texture morphology and charge carrier transport as mesoscopic parameters and the local electronic structure as molecular

parameters. As we always determine the reactivity during spectroscopic observation we aim at constructing structure-function relations founded on causal interrelations.

Director:

Prof. Dr. Robert Schlögl

Tel: 49 30 8413 4400

Fax: 49 30 8413 4401

E-mail: acsek@fhi-berlin.mpg.de

Selected international cooperation projects

NoE: ERIC+ - Integrated Design of Catalytic Nanomaterials for a

Sustainable Production

GRAFOL - Graphene chemical vapour deposition: roll to roll

technology

Unicat - “Unifying Concepts in Catalysis“ Cluster of Excellence CoE

U.S. hosted

NSF, PIRE: “Molecular engineering for conversion of biomass-

derived reactants to fuels, chemicals and materials”, hosted by Univ.

of New Mexico

Emil: “Construction of a photon energy beamline and several

endstations @BESSY“

BasCat : “Activation of C2 – C4 hydrocarbons”

Industrial partners:

Süd-Chemie, BASF, Bayer, UOP, Dow Chemicals, VW

http://www.unicat.tu-berlin.de

http://idecat.org

http://www.unm.edu/~pire/

http://www.grafol.eu

The generalization of

these findings is

attempted by studying

an array of systems

and reactions as

indicated in the table.

The actual systems

under investigation

are presented in the

following description

of ongoing work. Table 1: Selected reactions and catalyst systems that have been studied in the

past in the department. Some of them are still active projects others are

currently not studied. The table indicates that in all cases we found active

phases being chemically and structurally different from the nominal parent bulk

phase. It is essential to incorporate this understanding about the nature of the

active phase in attempts to explain the function of catalysts in a given reaction.

We bring this insight to bear in the context

of chemical energy conversion. Here we

study the use of chemical reduction

reactions to store renewable primary

electricity in molecular species known as

“solar fuels”. Future sustainable energy

systems need besides solar electricity

also chemical energy carriers for multiple

applications. We thus need to be able to

freely convert all forms of energy carriers

into each other which is currently not the

case, at least on a technological scale as

indicated in scheme 2.

All this is only possible through our ability to device, implement and operate a broad range of analytical and synthetic methods. To this end we are most grateful to the many coworkers in our workshop facilities without their skillful

and patient support we could not operate at all in our department. The such-attained problem-oriented competencies form the basis of our activities and thus for organizing the department in groups presenting their collaborative

activities in the following material. We could not do our work without a significant operation at the BESSY synchrotron operated by HZB Berlin. We further have joined forces with BASF and TU Berlin in the joint laboratory BasCat

dealing with industrial aspects of the feedstock challenge being an integrated problem in the ongoing energy transformation. We are further engaged in multiple cooperative activities with academic partners and with industry as

indicated below. We do this predominantly to broaden our competence base and to get grounding with our understanding against practical application tests that we could not perform in an environment concentrated on

fundamental science. We interact intensely with other groups within our institutes and within the MPG in order to stay connected with and to utilize results from related fundamental studies.

Scheme 2. Interconversion of energy carriers. The methods indicated

in green are current or emerging technology on world scale. The

methods in red are not ready for such applications. The MPI CEC

focuses currently on the conversion of CO2 and N2 into energy carriers.

In our studies we find a

dynamic response of the

working catalyst to the local

chemical potential of

reactants that is defined by

multiple variables that we

have to control. The approach

is indicated in Scheme 1.

Scheme 1: The local chemical

potential in a catalytic reaction

as key variable for the

reactivity defined by the

surface coverage with

reactants in a Langmuir-

Hinshelwood reaction scheme

which we find a useful general

concept for our portfolio of

reactions. The variables in

yellow indicate the influence of

chemical dynamics onto the

reaction. Their addition to the

static model of a catalyst is

vital for bridging the gaps in

catalysis science.

welcome