Primary research subjects include catalysis and electrocatalysis for sustainable fuel synthesis and use, solar energy conversion to fuels, fundamental gas and condensed phase molecular dynamics, radiation chemistry, and advanced chemical separations for energy applications. Fundamental studies of neutrino properties are also conducted in several international collaborations in nuclear and particle physics.
Chemistry Department Seminar
""Tracking atoms and charges in metal catalysts under reaction conditions"
Presented by Anatoly I. Frenkel, Physics Dept, Yeshiva University, NY
10 am, Room 300, 3rd Floor, Chemistry Bldg. 555
Tuesday, September 8, 2015, 10:00 am
Hosted by: Alex Harris
In the last decade, complexity of catalytic nanoparticles attracted much attention as a major factor in catalytic processes. Atomic and electronic structure and dynamics of particles, as well as their interactions with support and adsorbates, are important descriptors of their catalytic activity. The main challenge is how to investigate these factors in a working catalyst, at high temperature and pressure, and how to do so without breaking the correlations between components of this complex system. I will give a brief overview of new methods developed recently to enable such combined studies under realistic reaction conditions. Our approach is to single out electronic charge of metal atoms in a cluster as an "observable" quantity and develop methods to "observe" it experimentally under realistic reaction conditions, and model theoretically. In this framework, complex interactions between metal and adsorbates, metal and support, and support and adsorbates can be all accounted for in terms of their effects on the cluster charge. I will review recent results utilizing this approach for a prototypical catalyst, 1nm Pt nanoparticles supported on silica. Using high energy resolution methods of X-ray absorption and emission spectroscopies (HERFD and RIXS), as well as in situ IR spectroscopy (DRIFTS) and electron microscopy, aided with first-principles (DFT) modeling, we deduced that the structure of atoms and charges in the catalyst is strongly heterogeneous and that it changes dynamically with the change in temperature and pressure of adsorbates (H2 or CO).
Advances fundamental knowledge of processes leading to efficient conversion of sunlight to viable chemical fuels.
Pursues an improved understanding of chemical catalysis for advanced fuels synthesis and energy conversion processes by elucidating catalytically important properties of well-defined surfaces, powders and nanostructures.
Applies both photoexcitation and ionization by short pulses of fast electrons to investigate fundamental chemical problems relevant to the production and efficient use of energy
Develops and applies high resolution spectroscopic and quantum theoretic tools to study the structure, dynamics, and chemical reactivity of molecular species relevant to hydrocarbon combustion.
Explores problems of electrocatalysis of fuel cell reactions focusing on platinum monolayer (PtML) electrocatalysts for the O2 reduction reaction, the electrocatalysts for ethanol and methanol oxidation to CO2, H2 evolution and H2 oxidation reactions.
Participates in international collaborations including Low Energy Neutrino Spectroscopy (LENS), "SNO+", the Daya Bay neutrino experiment, and the long-baseline neutrino experiment (LBNE)
Works to understand the underlying physical processes that determine the products and yield of chemical transformations relevant to energy-related chemistry on catalytic and nanostructured surfaces.
The Chemistry Department is part of Brookhaven National Laboratory's Energy Sciences Directorate.