Department Atomic-Scale Dynamics in Light-Energy Conversion
News
February 2023 – Renske is appointed as S-W2-Professor at TU Berlin!
Congratulations! Renske is now officially affiliated with the Institute of Optics and Atomic Physics at the Technical University Berlin. Check out the news!
Paper published in Nature Reviews Chemistry
Started during the pandemic, we finally finished our review paper on time-resolved transmission electron microscopy. What a tour de force! Check it out here in Nature Reviews Chemistry!
Our TOC figure in the JPC Letters. ©J. Phys. Chem. Lett. 2023, 14, 545−551
January 2023 - Hanna’s first first-author paper!
Congratulations Hanna! Our paper about the reversible and irreversible cation intercalation in NiFeOx oxygen evolution catalysts in alkaline media was published in The Journal of Physical Chemistry Letters. Together with our colleagues from the Leiden Institute of Chemistry at the Leiden university, The Netherlands, and from HZB, we studied the intercalation process by measuring the soft X-ray absorption spectra at the nickel L-edge as well as at the sodium and oxygen K-edges of this layered Ni0.8Fe0.2Ox electrocatalyst during the oxygen evolution reaction using NaOH as electrolyte. The spectra reveal a (reversible) increase in the sodium intensity at the intercalation potential, which also coincides with an increase in the nickel oxidation state. However, the reversible increase in intercalated Na+ ions did not lead to an increase in the water content of the catalyst layer, which suggests that the intercalation of Na+ has little effect on the catalyst morphology. Our work also supports previous electrochemical studies that Na ions from the electrolyte are being intercalated into the γ-phase of Ni-based electrocatalysts for water oxidation. For more information about this fascinating story, please click here.
A) Sketch and b) photograph of the dip-and-pull setup with the yellow iron hexacyanide solution in a beaker sitting in the vacuum chamber under ambient pressure conditions. The three electrodes are first c) dipped into the electrolyte solution and then d) pulled up, with measurements taken while slowly moving between positions d) and e). The liquid meniscus is clearly shown in the photograph of f). The dashed circle in b) highlights some small hydrogen bubbles at the counter electrode. © J. Chem. Phys. 157, 244701 (2022)
December 2022 - Our spectroelectrochemistry paper about operando measurements on iron hexacyanide using the dip-and-pull technique has been published in the Journal of Chemical Physics
What a nice Christmas present! Our ‘multi-synchrotron’ work between MAXIV, Lund, and BESSY II, Berlin, on X-ray photoelectron spectroscopy of the redox reaction of iron hexacyanide has been published in JCP as part of the Special Topic on ‘In situ and Operando characterization’. While our colleagues around Robert Temperton from the HiPPIE beamline at MAXIV performed ambient-pressure XPS measurements using the so-called dip-and-pull technique to study the conversion of [FeIII(CN)6]3− in water into [FeII(CN)6]4− and following the (reversible) iron 2p signal, Robert and Wilson at HZB measured the reference iron 2p spectra with the liquid-jet technique for both redox states with the SOL³PES setup at BESSY II. The dip-and-pull technique is a fairly new technique in which a thin liquid film is prepared by pulling an electrode out of a degassed solution beaker in a ‘vacuum’ chamber equilibrated by the vapor pressure of the electrolyte solution (in case of water, ~10 mbar at 10°C). Our study demonstrates that the liquid film on the electrode is electrochemically active such that the relative potential difference between the working electrode and the solution can be controlled to a large extent. For more information about this technically demanding experiment, please click here.
Iain shows Robert the newest installations in the temperature and humidity-controlled level-5 clean room in the LIDUX lab. © Robert Seidel / HZB
November 2022 – Visiting LIDUX Laser Lab
Robert has visited Iain Wilkinson in his new state-of-the-art ‘Liquid and Interfacial Dynamics with Ultrafast X-rays facility’, LIDUX, at the Wannsee campus of HZB. Liquid jet and flatjet experiments with this impressive, powerful 500 W laser system will be available by the end of 2023. It will then be possible to observe ultra-short femtosecond processes after UV/Vis excitation by probing them with few-femtosecond soft X-ray pulses, capable of kicking out electrons from deeper lying core-orbitals that offer much cleaner spectral fingerprints compared to electrons ejected from the valence band. This laser offers the excellent time resolution of an X-ray free-electron laser, but does not generate any unwanted space charges in the samples due to lower pulse intensity and a much higher repetition rate of 53 kHz. Check out more here.
Top: Robert, Garlef and Dennis smile before the PhD defense. Middle: The smiling continues when Garlef received his doctorate hat from Dennis. Bottom: Garlef and Jan Lüning explore the richly decorated hat and its stories. ©Robert Seidel / HZB
Garlef Wartner is now Dr. Garlef Wartner!
Congratulations Garlef! With many, many spectroscopy-related questions from the PhD committee, consisting of the reviewers Simone Raoux (HZB/Humboldt University), Olle Björneholm (Uppsala University), and Robert, as well as the Humboldt University professors Oliver Benson, Emil List-Kratochvil, and Jan Lüning, Garlef delivered a brilliant performance in his defense. Overall, his PhD was graded with magna cum laude. Garlef will continue his work on electrochemical water splitting-cells in the group of Marc Tesch from the Max Planck Institute for Chemical Energy Conversion in Mülheim an der Ruhr, but will stay in Adlershof and work in collaboration with the Fritz Haber Institute Berlin and HZB. So, it is not time to say goodbye yet.
PS-ADLU is on the hunt! First, we strengthen ourselves at an Indian restaurant (upper left). There was some time for mulled wine between the individual quests (upper right). Everyone was happy after the successful hunt (lower left). The various stations to which our scavenger hunt led us (lower right).
November 2022 - We spent our annual excursion on a scavenger hunt through downtown Berlin
After a rich Indian meal in the Amrit restaurant on Oranienburger Straße, we started a scavenger hunt through Berlin, where we had to solve many puzzles and quests. Because we solved them so efficiently, we had plenty of time between the quests for some mulled wine at the Christmas market on Bebelplatz. It was a wonderful afternoon!
Top: Robert is fixing a leaking connector on the liquid microjet injector. Bottom: The most important people of the beamtime: Francis, Robert, Robert, Lewis, and Kevin. ©Robert Seidel / HZB
November 2022 Beamtime at MAXIV
Robert joined Kevin Lovelock and his team from Reading University for a four-day beamtime at MAXIV in Lund, Sweden. We studied the resonant Auger spectra of zinc salts in different solvents and were particularly interested in the participator Auger fingerprints of the anions and looked for trends in the (valence) binding energies upon changing the solvent. This work began in an earlier beamtime by Kevin Lovelock at BESSY II with the SOL³PES and is now being continued at the HiPPIE endstation at MAXIV, which is managed by Robert Temperton. After careful data analysis by the PhD students Lewis and Francis, the data from both synchrotron beamtimes will (hopefully) find their way into a publication.
Two different nanodiamond materials were investigated: C230H106 (left) and C286H68 (right). The grey and brown colored spheres represent hydrogen and fullerene-like carbon-atoms. Both species are needed for electron emission upon excitation with visible blue light. © T Kirschbaum / HZB
Christoph's paper on solvated electrons from nanodiamonds is published in Nanoscale!
Congrats, Christoph! Together with collaborators from Paris-Saclay, France, Uppsala University, Sweden, University of Stuttgart, Free University Berlin and Julius-Maximilians-University Würzburg as well as with colleagues from HZB, Franziska Buchner, Thorren Kirschbaum, Annika Bande and Tristan Petit, they were able to show for the first time spectroscopically the emission of solvated electrons from nanodiamonds with hydrogen and fullerene-like carbon on the surface upon excitation with visible blue light. Without these species at the surface, deep UV-light is needed and no electron emission upon visible light excitation was detected. This result is a big step forward and will put nanodiamonds with hydrogen/fullerene surface ‘treatment’ in the spotlight as potential candidates for photocatalysts used for CO2-reduction or nitrogen-to-ammonia conversion. Check out the paper here as well as the HZB press release here.
Hanna spoils us during group meeting!
What a treat! Hanna made vegan, vegetarian, and carnivore bread sticks. Yum!
Article published in Angewandte Chemie!
Our article on Ni-based photoredox catalysis was published in Angew. Chem. ! This work resulted from a collaboration with the groups of Arne Thomas, Bart Pieber, Henrike Müller-Werkmeister, and Josh Vura-Weis. Check it out.
Hungry, but happy: (from left to right) Jack, Laura, Rachel, Thomas, Renske, Conner and Tyler are waiting for the Mexican food in a restaurant in Lemont, Illinois. © Renske van der Veen / HZB
September 2022 - Beamtime at the APS
Renske and Thomas joined Rachel’s and Jack’s beamtime at the Advanced Photon Source at Argonne National Laboratory just south of Chicago. It was an exhausting but successful six-days/24-hours transient-hard-X-ray-absorption-measurement marathon of bimetallic molecular complexes relevant for photocatalysis.
After careful subtraction of the gas-phase ammonia spectrum, we were able to identify a broad shoulder in the nitrogen 1s Auger spectrum that can be assigned to ICD and shake-up satellite states. © Structural Dynamics 9, 044901 (2022)
August 2022 - Our article about intermolecular Coulombic decay in liquid ammonia has been published in Structural Dynamics.
Our colleagues from FHI (Winter group) and from Prague (Slavíček group and Hanns Christian Schewe from Jungwirth group) together with Robert measured Auger spectra of liquid ammonia for the first time. The intermolecular Coulombic decay (ICD) fingerprints are hidden under a shoulder on the high-energy side of the normal nitrogen Auger peak overlaid by shake-up satellites. In ICD, an initially core or inner-valence ionized atom or molecule electronically decays, and the released energy ionizes a neighboring entity via Coulombic electron interactions. Thanks to the theorists from Prague, we were able to deconvolute the messy Auger-peak structure, and our calculations support that ICD does indeed contribute. Liquid ammonia is a hydrogen-bonded system, and the electronic processes can couple to nuclear dynamics following core-level ionization. Unlike in liquid water, we found no significant proton-transfer dynamics occurring between the hydrogen-bonded units within the respective N 1s core-hole lifetime. You can read more about this fascinating basic-research study here.
Aswin on his first tour through the BESSY II synchrotron. © Hanna Trzesniowski / HZB
August 2022 - Welcome Aswin!
Phd candidate Aswin Jyothilakshmi Ravi (in short JR) from Kozhikode, India, joined PS-ADLU. A very warm welcome!
Robert next to his poster at the GRC in Holderness, New Hampshire. © Robert Seidel / HZB
July 2022 - Gordon Research Conference in Holderness
After a three-year hiatus due to the Corona pandemic, Robert attended the Gordon Research Conference of Water and Aqueous Solutions in Holderness, New Hampshire, USA. He presented recent liquid microjet data from sulfuric acid in water. From the valence and core-level spectra we can derive the dissociation constant as a function of probing depth, temperature and concentration. These dissociation constants are important input parameters for various climate (change) models, since aqueous aerosols of sulfate and bisulfate ions play a crucial role in cloud formation.
July 2022 - Our department becomes part of the UniSysCat cluster
UniSysCat stands for Unifying Systems in Catalysis, which is a Cluster of Excellence. More than 260 researchers from four universities and four research institutes in the Berlin and Potsdam area work together on current challenges in the highly relevant field of catalysis.
We are looking forward to many fruitful collaborations!
July 2022 - Thomas attends the Ultrafast Phenomena conference
Together with Jack and Rachel from UIUC he enjoyed many good talks & French croissants...
Thomas, Jack & Rachel enjoying themselves in Montreal
The weather changed dramatically during the two-day retreat. ©Robert Seidel / HZB
June 2022 - HZB retreat in Schmöckwitz
Our annual 2-day retreat for all group leaders at the HZB took place in beautiful Schmöckwitz, located at the very east of Berlin on the border to Brandenburg. A tightly packed schedule with talks, presentations and group discussions on the strategies and future plans of BESSY II and III awaited Renske and Robert.
Martin Gruebele and Renske van der Veen on big tour through BESSY II: control room (upper left), experimental hall (upper right), in the BESSY tunnel (lower left), at the SOL³PES station (lower right). © Robert Seidel / HZB
June 2022 - Martin Gruebele from the University of Illinois at Urbana-Champaign visited us.
Martin is a former colleague of Renske in the Department of Chemistry at the University of Illinois at Urbana-Champaign. Renske and Robert gave Martin a detailed tour through the BESSY synchrotron tunnel and the storage ring. Thanks to the ongoing shutdown we could show him all sacred places at BESSY II.
March/April 2022 - Jack, Rachel & Conner visit BESSY II
PhD students Jack, Rachel, and Conner from UIUC flew all the way from Illinois to Berlin for three weeks of beam time at the UE52_SGM beam line at BESSY.
May 2022 - PS-ADLU grows!
Robert Seidel and his group joined Renske van der Veen’s Department of Atomic-Scale Dynamics in Light-Energy Conversion (PS-ADLU). A warm welcome everyone!