Prof. Dr. Wolfgang Grünert

 Prof. Dr. Wolfgang Grünert

NBCF 04/686          0234 32 22088        w.gruenert@techem.ruhr-uni-bochum.de

SFB 558    SFB 558    Auslandsstudium: Auslandspraktikum: ERASMUS: ERASMUS-Praktika

Science in its mature state provides tools to predict the behaviour of systems on the basis of theoretical principles. Despite its tremendous relevance in chemical industry and in environ¬mental protection, het¬erogenous catalysis was far from this state until recently and was some¬times referred to as black magic rather than as science. Meanwhile, intensive research con¬centrating multiple structural and spectroscopic techniques on selected catalysts, studies of the surface state dur¬ing the catalytic reaction, and the close interaction with neighbouring fields of science which contribute investigations on simplified model systems (surface science, theo¬retical chemis¬try, homogeneous catalysis) have changed this situation. For major fields of heterogenous catalysis (acid-base, metal catalysis), prediction of reaction rates per active site on the basis of theoretical calculations has been recently demonstrated for simple systems.

However, heterogeneous catalysis remains an exciting experimental science with strong interdisciplinary impact. The immense complexity of real catalysts and of the routes for their synthesis, the dynamic development of preparation techniques for solid materials and the considerable economic and ecologic benefit from the application of improved catalysts create ever new tasks, which are even nowadays solved not so much by theoretical prediction but in the style of a scientific detective work (often including the use of theoretical tools).

The “structure/activity group” at the Laboratory of Industrial Chemistry in engaged in application-oriented basis research in heterogeneous catalysis, in particular in the knowledge-based development of catalysts. Its focus is the elucidation of relations between structural properties of catalysts and their catalytic behaviour as a first step towards the identification of molecular reaction mechanisms and the role of the catalytic sites in them. Such effort is concentrated on iron- or vanadium-based catalysts for exhaust-gas purification, e.g. by selective reduction of the nitrogen oxides in them by different reductants, on gold-titania model catalysts for low-temperature oxidation of carbon monoxide, on model catalysts for the study of metal-support-interactions, and on sulfide catalysts for catalytic hydrorefining of oil fractions. Recently, it has been extended to the oxygen reduction reaction on the cathode of proton-exchange membrane fuel cells. Typical methods applied to these catalysts are X-ray absorption spectroscopy (XANES, EXAFS), photoemission techniques (XPS, UPS) and Ion scattering (LEIS). Other methods are accessed via cooperations.

Selected publications
  1. Anomalous surface compositions of stoichiometric mixed oxide compounds, S. V. Merzlikin, N. N. Tolkachev, L. E. Briand, T. Strunskus, C. Wöll, I. E. Wachs, W. Grünert, Angew. Chemie Int.. Ed. 2010, 49, 8037-8041.

  2. Alkene Epoxidation with mesoporous materials assembled from TS-1 seeds – is there a hierarchical pore system ?, M. Reichinger, W. Schmidt, M. W. E. van den Berg, A. Aerts, J. A. Martens, C. E.A. Kirschhock, H. Gies, W. Grünert, J. Catal. 2010, 269, 367-375.

  3. Dynamical Changes in the Cu-ZnOx interaction observed in a model methanol synthesis catalysts, M. W. E. van den Berg, S. Polarz, O. P. Tkachenko, K. Kähler, M. Muhler, W. Grünert, Catal. Lett. 2009, 128, 49-56.

  4. Mechanochemical activation of MoS2 – Surface properties and catalytic ac­tivities in hydrogenation and isomerization of alkenes and in H2/D2 exchange, M. Polyakov, S. Indris, S. Schwamborn, A. Mazheika, M. Poisot, W. Bensch, M. Muhler, W. Grünert, J. Catal. 2008, 260, 236-244.

  5. The role of NO2 in the Selective Catalytic Reduction of Nitrogen Oxides over Fe-ZSM-5 Catalysts – Active Sites for the Conversion of NO and of NO/NO2 mixtures, M. Schwidder, S. Heikens, A. De Toni, S. Geisler, M. Berndt, A. Brückner, W. Grünert, J. Catal. 2008, 259, 96-103.

  6. Hydrocarbon reactions on MoS2 revisited, I: Activation of MoS2 and interaction with hydrogen studied by transient kinetic experiments, M. Polyakov, M. W. E. van den Berg, T. Hanft, M. Poisot, W. Bensch, M. Muhler, W. Grünert ,  Journal of Catalysis, 2008, 256, 126-136

  7. Hydrocarbon reactions on MoS2 revisited, II: Catalytic properties in alkene hydrogenation, cis-trans isomerization, and H2/D2 exchange, M. Polyakov, M. Poisot, W. Bensch, M. Muhler, W. Grünert,  Journal of Catalysis, 2008, 256, 137-144

  8. Resolving the Depth Coordinate in Photoelectron Spectroscopy – Comparison of Excitation Energy variation vs. Angular-resolved XPS for the Analysis of a Self-assembled Monolayer System, S. V. Merzlikin, N. N. Tolkachev, T. Strunskus, G. Witte, T. Glogowski, C. Wöll, W. Grünert, Surface Science 2008, 602, 755-767.

  9. Cu/ZnO aggregates in siliceous mesoporous matrices: Development of a new model methanol synthesis catalyst, M.W.E. van den Berg, S. Polarz, O.P. Tkachenko, K.V. Klementiev, M. Bandyopadhyay, L. Khodeir, H. Gies, M. Muhler, W. Grünert, Journal of Catalysis, 2006, 241, 446-455

  10. Selective Reduction of NO with Fe-ZSM-5 Cata­lysts of Low Fe content I. Relations between Active Site Structure and Catalytic Performance, M. Schwidder, M. Santhosh Kumar, K. Klementiev, M. M. Pohl, A. Brückner, W. Grünert, J. Catal. 2005, 231, 314-330.