Lectures and Events - Department of Materials and Interfaces

Upcoming Lectures

  • March18

    11:00 AM

    Gerhard M.J. Schmidt Lecture Hall

    Atom-Probe Tomography and its Myriad Applications in Chemistry

    Prof. David N. Seidman

    atom-probe tomograph (APT) can dissect a nanotip shaped specimen (radius <50 nm) atom-byatom and by atomic...

    atom-probe tomograph (APT) can dissect a nanotip shaped specimen (radius <50 nm) atom-byatom and by atomic plane-by-plane, and then the dissected volume can be reconstructed from the positions of the atoms in three-dimensions (3-Ds), with atomic-scale resolution plus assigning an elemental or isotopic identity to each atom with a detection efficiency of ~80% (E. W. Mueller, J. A. Panitz, S. B. McLane, 1968). To be specific an APT consists of a field-ion microscope (FIM), which one uses to observe individual atoms on the surface of a nanotip with atomic resolution ( E. W. Mueller and Bahadur, 1956).plus a special time-of-flight (TOF) mass spectrometer to determine the mass-tocharge state ratio (m/n) of each charged field-evaporated atomic or molecular ion: the nanotip is at a positive potential with respect to ground. In a modern APT a picosecond ultraviolet (UV) laser, operating in a pulsed mode, is utilized to thermally activate field-evaporated atoms from the surface of a nanotip as positively charged ions. The ions are detected using a microchannel plate (MCP) detector, with a gain of 107, which serves as the primary detector of the evaporated ions, which, in turn, yields their m/n values from their TOFs. Behind the primary detector is a secondary detector, which yields the 2-D positions of the field-evaporated ions in different {hkl} planes on the surface of a nanotip, which to first order is a highly faceted hemisphere. With continuing pulsed field-evaporation the atoms in the bulk of a nanotip are sequentially detected, thereby yielding the 3rd dimension and hence the name atom-probe tomograph (APT). In addition to the functional principles of an APT, select research applications are presented.

  • March20

    11:00 AM

    Perlman Chemical Sciences Building

    Room 404

    Employing the Hegelian Aufhebung Principle for Predicting New Catalytic Pathways

    Prof. Anatoly Frenkel

    Understanding mechanisms of work for a wide range of applied nanomaterials begins with identifying “active units” in...

    Understanding mechanisms of work for a wide range of applied nanomaterials begins with identifying “active units” in operating conditions, zooming in on the “active sites” and ends with a model explaining their role for functioning of the material or device. There are two main hurdles that we are particularly interested in overcoming: 1) heterogeneity of active species and sites and 2) their dynamics that can be directly responsible for their mechanisms. One possible method, ideally suitable for capitalizing on these challenges for rational design of new catalytic pathways, is the Aufhebung (sublation) principle from the Hegelian dialectics. It describes the process of advancing knowledge by integrating the two opposites: the thesis and antithesis. We adopt this principle to leverage the inherent heterogeneity of catalytic active species and active sites in metal catalysts for understanding and predicting new catalytic pathways for CO and CO2 conversion reactions. Starting with atomically dispersed (the thesis) Pt on ceria support, we use multimodal, operando characterization for monitoring formation of nanoparticles (the antithesis), identify reaction active species and unique active sites at the metal-support interface. With this knowledge, we design the “single-atoms” catalysts (synthesis) possessing the same active sites and enhanced stability in reaction conditions. I will highlight the role of oxygen vacancies for enhancing the dynamicity of Pt atoms and opening new reaction pathways for direct and reverse water gas shift reactions and CO oxidation reaction.

  • March27

    11:00 AM

    Perlman Chemical Sciences Building

    Room 404

    Exploring Inorganic and Organic Biomass for generation of Fuels and Chemical Commodities

    Dr. José Geraldo Nery

    Biomass is characterized as "material of biological origin, excluding material embedded in geological...

    Biomass is characterized as "material of biological origin, excluding material embedded in geological formations or fossilized." It serves as a valuable resource for energy production and as a foundational material for the synthesis of various commodity and specialty materials. The composition of biomass is notably more diverse and intricate than that of crude oil, resulting in significant distinctions between a conventional petroleum refinery and a biomass refinery, often referred to as a biorefinery. Unlike crude oil, which is typically abundant in gaseous, liquid, and solid hydrocarbons featuring a high carbon-to-oxygen (C/O) ratio, biomass primarily consists of complex biomacromolecules with a considerably lower C/O ratio. The conversion of biomass into commodity chemicals presents a promising approach to diminish society's reliance on fossil fuel resources—the predominant challenge of the 21st century. This challenge necessitates the development of tools and technologies to facilitate the transition from a predominantly petroleum-based to an alternative bio-based chemical industry. The objective of this seminar is to showcase the recent advancements we have made in enhancing bio-based platform molecules for the production of commodity or specialty chemicals. We achieve this through the utilization of C2 to C6 bio-based platforms, exemplified by polyols (e.g., glycerol), furanoids (e.g., furfural), and carboxylic acids (e.g., levulinic acid).

  • May27

    11:00 AM

    Gerhard M.J. Schmidt Lecture Hall

    AI (R)Evolution in Chemistry and Physics

    Prof. Alexandre Tkatchenko

    Learning from data has led to paradigm shifts in a multitude of disciplines, including web, text and image search and...

    Learning from data has led to paradigm shifts in a multitude of disciplines, including web, text and image search and generation, speech recognition, as well as bioinformatics. Can machine learning enable similar breakthroughs in understanding (quantum) molecules and materials? Aiming towards a unified machine learning (ML) model of molecular interactions in chemical space, I will discuss the potential and challenges for using ML techniques in chemistry and physics. ML methods can not only accurately estimate molecular properties of large datasets, but they can also lead to new insights into chemical similarity, aromaticity, reactivity, and molecular dynamics. For example, the combination of reliable molecular data with ML methods has enabled a fully quantitative simulation of protein dynamics in water (https://arxiv.org/abs/2205.08306). While the potential of machine learning for revealing insights into molecules and materials is high, I will conclude my talk by discussing the many remaining challenges.

  • November18

    11:00 AM

    Gerhard M.J. Schmidt Lecture Hall

    Annual Gerhard Schmidt Lecture

    Prof. Angel Rubio

  • December16

    11:00 AM

    Gerhard M.J. Schmidt Lecture Hall

    title tbd

    Prof. Anke Weidenkaff

  • February17

    11:00 AM

    Gerhard M.J. Schmidt Lecture Hall

    title tbd

    Prof. Christian A. Nijhuis

  • March17

    11:00 AM

    Gerhard M.J. Schmidt Lecture Hall

    title tbd

    Prof. Wim Noorduin