Scientifika image

We warmly invite you to participate in a new series of scientific seminars organised by the User Office at MAX IV, Lund University

Where – Virtual format by Zoom call https://lu-se.zoom.us/j/61349123545
When – Mondays 13:45 CET
Format – 30 minutes of presentation followed by 15 minutes of discussion, chaired by MAX IV staff

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Programme

Monday 17 January 2022, 13:45 CET
Using Synchrotron XPS at low and high pressures to study the reaction mechanism of Fischer-Tropsch Synthesis on Cobalt Catalysts

Speaker: Dr Kees Jan Weststrate, Deputy Director of Syngaschem BV, The Netherlands

Host: Dr Andrey Shavorskiy, manager at HIPPIE beamline

Keywords: catalysis, surface sensitive analysis, Fischer-Tropsch synthesis,  XPS

Catalysis plays a crucial role in the chemical industry and it is an important topic in fundamental research. In heterogeneous catalysis the reactants bind to the surface of the catalyst where they react and form the desired product. All the action takes place in the outermost atomic layer of the catalyst material and surface sensitive analysis tools are needed to better understand how catalysts work. In my lecture I will discuss how synchrotron XPS can be used as a powerful surface analysis technique tool to obtain fundamental insights into the reaction mechanism of Fischer-Tropsch synthesis (FTS) on cobalt catalysts. This is an important reaction in which metallic cobalt nanoparticles catalyse the conversion of carbon monoxide and hydrogen (synthesis gas) into long hydrocarbon chains. This process is expected to play an important role in the future, since synthesis gas can be produced from renewable feedstocks. FTS can then be used to produce sustainable fuels and chemicals.

 

Monday 24 January 2022, 13:45 CET
Time-resolved and event-averaged
ambient pressure x-ray photoelectron spectroscopy

Speaker: Dr Jan Knudsen, MAX IV, Lund University

Host: Dr Andrey Shavorskiy, manager at HIPPIE beamline

Ambient pressure x-ray photoelectron spectroscopy (APXPS) is an excellent in-situ characterization technique for catalytic active surfaces as it is able to characterize the surface, adsorbates, and the gas-phase just above the surface simultaneously and while a chemical reaction is running. Unfortunately, the technique is slow with seconds or minutes of acquisition time per spectrum. This limits its use to identifying the equilibrium and majority phases present while the catalyst is active and makes the time domain inaccessible excluding for example studies of kinetic processes.

In this talk, we will demonstrate how this limitation can be overcome by the construction of event-averaged data from stroboscopic APXPS data acquired in a cyclic reaction environment [1]. Using a transient gas supply with rapidly changing composition, we will show how one can force a surface to oscillate between active and inactive phases using CO oxidation and Pd(100) as model reaction and surface, respectively. Ultimately, I will demonstrate that one can record spectra with 60 ms time resolution with an efficient acquisition time of 30 s by averaging over more than 500 events. The scientific case stories in my talk will include examples both acquired in mbar pressures at the HIPPIE beamline, MAX IV, and at ~100 mbar at the new POLARIS instrument, DESY.

As an outlook of my talk I will discuss temperature pulses, ultra-fast pump-probe experiments using gas composition pulses, and in general where event-averaged and time-resolved APXPS and the methodology applied to other synchrotron based techniques can take us in the future.

 

Monday 31 January 2022, 13:45 CET
Synthesizing high-quality 2D materials: from surface science to the industry of tomorrow

Speaker: Dr Camilla Coletti, 2D Materials Engineering Group Leader, Center for Nanotechnology Innovation @NEST, Italy
Host: Dr Alexei Zakharov, manager at MAXPEEM beamline

Keywords: graphene, 2D materials, photonic applications, chemical vapor deposition, twistronics and van der Waals heterostacks

Graphene is a material with great potential for photonic applications. To make it realistically appealing at high technology readiness levels (TRLs) a feasible way to scale-up high-quality material with bottom-up synthetic approaches has to be found. In this talk, I will present our approaches in this direction and how we adopt surface and interface science to impact science and technology of 2D materials. I will present different wafer-scale growth approaches of high-quality graphene via chemical vapor deposition (CVD) and show how this material can be straightforwardly integrated on existing photonic platforms. Furthermore, I will present results on the field of twistronics and van der Waals heterostacks, which are an exciting playground for fundamental studies.

 

 

About ScientiFika

The initiative aims to share knowledge and stimulate enthusiastic discussions on synchrotron research and methods developed at MAX IV. These shall be a channel to learn more about our facility, strengthen collaborations, bring communities together and promote cooperation and interdisciplinarity.

The speakers will be MAX IV past, current and potential future users, as well as MAX IV staff; on the other hand, welcome attendees are members of the broad scientific community: scientists from the speaker´s home institution, of Swedish and international universities as well as MAX IV and other light sources staff.

Please reach us through the email of the in case you have any comments or suggestions regarding the series.

We look forward to seeing you online and hope you enjoy the talks!

 

  • name Doriana Orbanic
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