Time: 9:00-12:00 October 11 2016
Venue：Conference Hall of Basic Energy Science Building
Lecture 1：Catalytic Conversion of Sugars Using Tin-containing Silicates
Time： 9:00-9:55 AM
Speaker：Dr. Esben Taarning
Senior Research Scientist at Haldor Tops?e A/S, R&D program leader for Bio2Chemicals. He obtained his M. Sc. in Chemistry from Copenhagen University in 2005 working in the field of MPVO redox using soluble Lewis acids. In 2009 he obtained his Ph.D. from The Technical University of Denmark working on catalysis related to sustainable feedstocks. In 2009 he started working for Haldor Tops?e R&D and in 2012 became R&D program leader for the Bio2Chemicals program. His research interests are organic chemistry, sugar conversion, sustainable reactions and industrial applications.
Tin-containing silicates such as Sn-Beta display a unique catalytic ability for the conversion of sugars in alcohol solvents at temperatures in the range of 130-180 ?C to produce a variety of a-hydroxy carboxylic acid esters which may be useful polyester building blocks. The products are formed through a cascade of reactions involving 1,2-hydride shifts, retro-aldol reactions and b-dehydration reactions. By tuning the reaction conditions and adding alkali salts, it is possible to optimize the selectivity to methyl lactate (75%) and in the absence of alkali, novel C6-esters are formed instead. The presentation will highlight recent developments in this area.
Lecture 2：Mechanistic Studies of Reactions over Mehanation, Steam Reforming, and Methanol Synthesis Catalysts
Time： 9:55-10:50 AM
Speaker：Dr. Jens Sehested
Jens Sehested received his Ph.D. in chemistry in 1994 from Copenhagen University and worked as a research scientist and senior research scientist at Ris? National Laboratory with gas phase degradation of pollutant in the atmosphere including alternatives to Freon until 1998 where he joined Haldor Tops?e A/S. At Haldor Tops?e he worked as research scientist, senior scientist, project manager and program manager with the development of catalysts in the synthesis gas area including catalysts for the ammonia, steam-reforming, methanation, high temperature methanation, methanol, water gas shift, higher alcohol and dimethyl ether processes. The work has involved kinetic studies and modelling of heterogeneous reactions over ammonia, steam reforming, methanation and dimethyl ether. Scientifically, his work was focused on fundamental understanding of catalysts for ammonia, steam reforming, methanation and methanol synthesis. Jens Sehested has authored more than 110 scientific publications and is in the advisory board for the Department of Chemistry at Copenhagen University.
Lowering the apparent activation energies of desirable chemical reactions can often be achieved by applying heterogeneous or homogeneous catalysts. Industrially, commodity chemicals are commonly formed via a series of large reactors containing highly optimized catalysts. As an industrial catalyst turnaround is expensive, mainly due to loss of production, the commercial interest in improving the profitability is strong and the potential economic impact of improving catalyst activity and stability is high. To optimize well-established commercial processes where heterogeneous catalysts are applied, the chemical industry and academia pursue a deeper understanding of the catalyzed reactions and the reaction mechanisms to optimize and improve plant performance. Here, reactions in three well-established commercial processes will be examined in some detail: the reaction mechanisms for methanation over nickel catalysts and for steam reforming over transition metals is considered and the effect of ZnO in industrial-type methanol synthesis catalysts will be discussed. The main emphasis will be on understanding of the fundamental mechanisms for catalyst activity at the microscopic level.
Lecture 3：Transmission Electron Microscopy of MoS2-based Hydrodesulfurization Catalysts
Speaker：Dr. Michael Brorson
Ph.D. in chemistry, University of Copenhagen in 1987; 1987-95 Chemistry Department A, The Technical University of Denmark (1991-95 Associate Professor/Senior Lecturer ("lektor"); 1987-91 Assistant Professor/Lecturer ("adjunkt"));1992 & 94 Research School of Chemistry, Australian National University, Canberra (Visiting Fellow); 1995- Haldor Tops?e A/S, Denmark (1995-00 Research Chemist; 2001-11 Principal Research Chemist; 2012- Senior Research Scientist; 2001-06 Section Head, Chemistry Group; 2003-06 Project Manager, Explorative R&D; 2006-2011 Project Manager, Refinery Department; 2012- Program Leader, Refinery R&D).He has 8 Patents and more than 70 Scientific publications in international, peer-reviewed journals. His research interests mainly focus on fundamental and applied studies in hydrotreating catalysts.
Increasingly stringent legislation regarding the maximum allowed sulfur content in mineral oil based fuels means that oil refinery hydrodesulfurization (HDS) must be improved. To aid the development of more active catalysts, a detailed understanding of the structure-activity relationship for the catalysts is highly desired. MoS2 constitutes the active component of industrial HDS catalysts and it is the edges of the MoS2 layer-structure that host the active sites, typically by way of attached Co or Ni promoter atoms. Previously, detailed information about single-layer MoS2 nanoparticles has been obtained from scanning tunneling microscopy (STM) of model systems prepared under ultra-high vacuum conditions and from density functional theory calculations. In the current studies single-atom sensitive, state of the art electron microscopes were used to analyze samples prepared in the same way as industrial catalysts. Aqueous incipient wetness impregnation of high-surface area graphite with a molybdenum salt, followed by high-temperature treatment with gaseous H2S/H2 mixtures, yielded supported MoS2 nanoparticles.
The use of HRTEM (High Resolution Transmission Electron Microscopy) and HRSTEM (High Resolution Scanning Transmission Electron Microscopy) has allowed us to address the location of cobalt atoms on the MoS2 nanoparticles and also the precise atomic arrangement of Mo and S. With the detailed edge-structures known, a description of the reactivities of various sites to organosulfur molecules is made possible. Of particular interest is how the relative chemical potentials of H2 and H2S in the gas mixture used for MoS2 synthesis determine the edge-terminations and, more generally, the structure of those edges where promoter atoms (Co or Ni) are located.
Active hydrodesulfurization catalysts are obtained industrially by sulfidation of oxidic catalysts. This involves a transformation of MoO3-like structures to MoS2 structures. The progress of such a reaction has been studied by in situ TEM. Starting from a sub-monolayer of MoO3 dispersed on an oxide support (MgAl2O4) exposure to H2S/H2 is seen to lead to formation of single-layer MoS2 nanocrystals that grow in extension with time. Relatively infrequently, second or third MoS2 layers will start growing on top of the initial MoS2 layer.