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  1. SEP

    12

    Thursday

    Chemistry Department Colloquium

    "Oxygen Catalysis for Large Scale Solar Energy Harvesting and Storage"

    Presented by Dunwei Wang, Boston College

    11 am, Hamilton Seminar Room, Bldg. 555

    Thursday, September 12, 2019, 11:00 am

    Hosted by: Anatoly Frenkel

    : As we enter Anthropocene, it has become clearer than ever that a sustainable future will be one built on renewable energy resources. A critical challenge in realizing such a goal is to harvest and store renewable energy efficiently and inexpensively on a terawatt scale. Of the options that have been examined, using the energy to directly synthesize fuels stands out. When the renewable energy source is solar, the process is often referred to as artificial photosynthesis, highlighting the similarities with natural photosynthesis. Within this context, we have focused on understanding the detailed processes that are important to artificial photosynthesis. More specifically, a main thrust of our research has been water oxidation by photochemical reactions on the surface of inorganic materials. We strived to understand the detailed physical and chemical processes at the solid/liquid interface, with the goal of enabling facile electron extraction from water for the eventual proton reduction for hydrogen generation or the carbon dioxide reduction for the production of complex organic compounds. It was discovered that the light harvesting and catalytic components in an integrated system exerts profound influences on each other in a complex fashion. Detailed studies generated new insights into the water oxidation reactions at the molecular level, some of which was readily transferred to other reactions such as methane transformation. These efforts also inspired us to study oxygen catalysis in aprotic systems for applications with more immediate implications, such as metal air batteries.

  2. OCT

    15

    Tuesday

    Chemistry Department Colloquium

    "DESIGN OF METAL/METAL-OXIDE HETEROGENEOUS CATALYSTS FOR ENERGY AND CHEMICAL CONVERSION"

    Presented by Eranda Nikolla, Wayne State University

    11 am, Hamilton Seminar Room, Bldg. 555

    Tuesday, October 15, 2019, 11:00 am

    Hosted by: Sanjaya Senanayake

    Dwindling fossil fuel resources and high levels of CO2 emissions have increased the need for renewable energy and efficient energy conversion and storage systems. In this talk, some of our recent work on designing efficient (active, selective and stable) catalytic systems for energy and chemical conversions will be discussed. First, I will highlight our work on designing layered nickelate oxide electrocatalysts for electrochemical oxygen reduction and evolution reactions. These processes play an important role in fuel cells, electrolyzers and Li-air batteries. We have utilized density functional theory (DFT) calculations to identify the factors that govern the activity of nickelate oxides toward these processes. Using a reverse microemulsion approach, we demonstrate an approach for synthesizing nanostructured nickelate oxide electrocatalysts with controlled surface structure. These nanostructures are thoroughly characterized using atomic-resolution high angle annular dark field (HAADF) imaging along with electron energy-loss spectroscopy (EELS) performed using an aberration corrected scanning transmission electron microscope (STEM). Controlled kinetic isotopic and electrochemical studies are used to develop structure/performance relationships to identify nickelate oxides with optimal electrocatalytic activity. Secondly, I will discuss our efforts on designing selective catalysts for biomass conversion processes. Development of active and selective catalysts for biomass conversion is critical in realizing a renewable platform for fuels and chemicals. I will highlight some of our recent work on utilizing reducible metal oxide encapsulated noble metal catalytic materials to promote hydrodeoxygenation (HDO) of biomass-derived compounds. We show enhancement in HDO activity and selectivity due to the encapsulation of the metal nanoparticles by an oxide film providing high interfacial contact between the metal and metal oxide sites, and restrictive acce

  3. OCT

    28

    Monday

    Chemistry Department Colloquium

    "Electronic Cooperativity in Supported Single and Multinuclear-Sites for Catalytic C-C and C-H Bond Functionalization"

    Presented by Dr. Massimiliano Delferro, Argonne National Laboratory

    11 am, Hamilton Seminar Room, Bldg. 555

    Monday, October 28, 2019, 11:00 am

    Hosted by: Sanjaya Senanayake

    Systematic study of the interactions between organometallic catalysts and metal oxide support materials is essential for the realization of rational design in heterogeneous catalysis. In this talk, I will describe the stoichiometric and catalytic chemistry of a series of organometallic complex chemisorbed on a variety of metal oxides as a multifaceted probe for stereoelectronic communication between the support and organometallic center. Electrophilic bond activation was explored in the context of stoichiometric hydrogenolysis as well as catalytic hydrogenation, dehydrogenation, and H/D exchange. Strongly acidic modified metal oxides such as sulfated zirconia engender high levels of activity toward electrophilic bond activation of both sp2 and sp3 C–H bonds, including the rapid activation of methane at room temperature; however, the global trend for the supports studied here does not suggest a direct correlation between activity and surface Brønsted acidity, and more complex metal surface interactions are at play.

  1. Atmospheric Chemistry Colloquium for Emerging Senior Scientist

    "ACCESS XV"

    Saturday, July 27, 2019, 8 am
    Berkner Hall, Room B

    Hosted by: Ernie Lewis

  2. Atmospheric Chemistry Colloquium for Emerging Senior Scientist (ACCESS XV)

    "ACCESS XV"

    Friday, July 26, 2019, 8 am
    Berkner Hall, Room B

    Hosted by: Ernie Lewis

  3. Chemistry Department Seminar

    "Nanoparticle Beam Deposition: A Novel Route to the Solvent-Free"

    Presented by Richard E. Palmer, Nanomaterials Lab, Swansea University, UK, United Kingdom

    Tuesday, July 16, 2019, 11 am
    Room 300, 3rd Floor, Chemistry Building 555

    Hosted by: Michael White

    Size-selected nanoparticles (atomic clusters), deposited onto supports from the beam in the absence of solvents, represent a new class of model systems for catalysis research and possibly small-scale manufacturing of selective catalysts. To translate these novel and well-controlled systems into practical use, two major challenges have to be addressed. (1) Very rarely have the actual structures of clusters been obtained from direct experimental measurements, so the metrology of these new material systems have to improve. The availability of aberration-corrected HAADF STEM is transforming our approach to this structure challenge [1,2]. I will address the atomic structures of size-selected Au clusters, deposited onto standard carbon TEM supports from a mass-selected cluster beam source. Specific examples considered are the "magic number clusters" Au20, Au55, Au309, Au561, and Au923. The results expose, for example, the metastability of frequently observed structures, the nature of equilibrium amongst competing isomers, and the cluster surface and core melting points as a function of size. The cluster beam approach is applicable to more complex nanoparticles too, such as oxides and sulphides [3]. (2) A second major challenge is scale-up, needed to enable the beautiful physics and chemistry of clusters to be exploited in applications, notably catalysis [4]. Compared with the (powerful) colloidal route, the nanocluster beam approach [5] involves no solvents and no ligands, while particles can be size selected by a mass filter, and alloys with challenging combinations of metals can readily be produced. However, the cluster approach has been held back by extremely low rates of particle production, only 1 microgram per hour, sufficient for surface science studies but well below what is desirable even for research-level realistic reaction studies. In an effort to address this scale-up challenge, I will discuss the development of a new kind of nanop

  4. Nuclear Physics Seminar

    "Charm hadron collective flow and charm hadrochemistry in heavy-ion collisions"

    Presented by Xin Dong, Lawrence Berkeley National Laboratory

    Tuesday, July 2, 2019, 10 am
    Small Seminar Room, Bldg. 510

    Hosted by: Lijuan Ruan

    Heavy quark transport offers unique insight into the microscopic picture of the sQGP created in heavy-ion collisions. One central focus of heavy quark program is to determine the heavy quark spatial diffusion coefficient and its momentum and temperature dependence. This requires precise measurements of heavy flavor hadron production and their collective flow over a broad momentum region. In the meantime, heavy quark hadrochemistry, the abundance of various heavy flavor hadrons, provides special sensitivity to the QCD hadronization and also plays an important role for the interpretation of heavy flavor hadron data in order to constrain the heavy quark spatial diffusion coefficient of the sQGP. In this seminar, I will focus on the recent STAR results of charm hadron D0, D+/-, D*, Ds, Lambda_c production and D0 radial and elliptic flow in heavy-ion collisions utilizing the state-of-the-art silicon pixel detector, the Heavy Flavor Tracker. These data will be compared to measurements from other experiments at RHIC and the LHC as well as various model calculations. I will then discuss how these data will help us better understand the sQGP properties and its hadronization. Finally, I will present a personal view of future heavy quark measurements at RHIC.

  5. Chemistry Department Seminar

    "Chemical and Electrochemical Studies of Half-Sandwich Rhodium Complexes"

    Presented by James D. Blakemore, Dept. of Chemistry, University of Kansas

    Tuesday, July 2, 2019, 10 am
    Room 300, Chemistry Bldg. 555

    Hosted by: Etsuko Fujita

    Understanding the management of protons and electrons (reducing equivalents) by transition metal compounds is an active area of research, in part because of the role of reduced and/or protonated complexes in catalysis and energy conversion. We have been studying the chemistry of half-sandwich rhodium complexes in this regard, in order to reveal the influence of ligand structure on the outcomes of reduction and protonation reactions. Here, recent results on use of hybrid [P,N] and dipyridylmethane [N,N] chelate ligands will be discussed, including preparation and characterization of new compounds, chemical and electrochemical experiments aimed at elucidating new reactivity patterns, and studies of hydrogen evolution. Taken together, the results suggest that relatively underexplored ligands, as analogues of common diimine and diphosphine chelates, offer interesting new opportunities for influencing the properties and reactivity of metal complexes with protons and electrons.

  6. Chemistry Department Colloquium

    "Recent Advances in Soft X-ray Spectroscopy towards a Direct and Reliable Probe of Chemistry in Batteries"

    Presented by Wanli Yang, Lawrence Berkeley National Laboratory

    Thursday, June 27, 2019, 2 pm
    Hamilton Seminar Room, Bldg. 555

    Hosted by: Enyuan Hu

    The pressing demand of improved energy storage systems, especially for electric vehicles and green-grid, calls for speedy strategies for developing materials based on advanced analytic tools. Synchrotron based soft x-ray core-level spectroscopy is one of such incisive tools that probes the key electronic states pertaining to the performance of batteries. This colloquium starts with an in-depth introduction of conventional soft X-ray absorption spectroscopy (XAS) and X-ray emission spectroscopy (XES) with its applications in detecting the critical electron states in battery materials from binder to electrodes. The experimental results provide both general understandings and quantitative analysis of the transition-metal (TM) reactions at different electrochemical states, through direct probes of the K-edges (2p states) of low-Z elements such as C, O, N, and the L-edges (3d states) of 3d TMs. More importantly, however, we clarify that conventional spectroscopic experiments based on XAS do not really provide the claimed "elemental sensitivity" in either the O-K or the TM-L in the bulk-sensitive photon-in-photon-out mode, thus failing to detect the true signature of the bulk redox reactions of lower TMs, and especially, Oxygen [1]. This naturally requires advanced spectroscopic probes beyond conventional XAS for disentangle the mixed signals in oxides. We show that high-efficiency mapping of resonant inelastic X-ray scattering (mRIXS) beautifully solves the problems in both TM-L and O-K edge characterizations, providing clear experimental signatures of both the TM [2] and Oxygen [3] redox that cannot be distinguished in conventional XAS. This colloquium does not focus on technical discussions of a specific scientific study, instead, the focus will be on clarifying the principle and on how to correctly interpreting soft X-ray spectroscopic data instead of following popular misinterpretations. We finally note that recent advances in bo

  7. Chemistry Department Colloquium

    "Molecular catalysis of small molecules activation."

    Presented by Cyrille Costentin, Université Paris Diderot, France

    Monday, June 17, 2019, 11 am
    Hamilton Seminar Room, Bldg. 555

    Hosted by: Gerald Manbeck

    Solar-driven electrochemical splitting of water to molecular hydrogen and oxygen, along with the reduction of carbon dioxide are small molecule transformations that hold promise as routes of storing sunlight in energy-dense chemical bonds. Activation penalties require the help of catalysts, usually transition metal derivatives. We will provide the basic principles of molecular catalysis of electrochemical reactions based on the use of cyclic voltammetry as an analytical tool. Two examples will be discussed in details: (i) catalysis of the CO2-to-CO conversion with iron porphyrins to illustrate how mechanism analysis can lead to an intelligent design of a catalyst; new results on CO2 vs. acid reduction selectivity will be discussed; (ii) catalysis of the O2-to-H2O conversion with manganese porphyrins showing the crucial role of proton couple electron transfer (PCET) in the process.

  8. Chemistry Department Seminar

    "Designing Dopants to Shield Anion Electrostatics in Doped Conjugated Polymers to Obtain Highly Mobile and Delocalized Carriers"

    Presented by Taylor Aubry, UCLA

    Thursday, May 23, 2019, 11 am
    Room 300, 3rd Floor - Chemistry Bldg. 555

    Hosted by: Matthew Bird

    Doping conjugated polymers is an effective way to tune their electronic properties for thin-film electronics applications. Chemical doping of semiconducting polymers involves the introduction of a strong electron acceptor or donor molecule that can undergo charge transfer (CT) with the polymer. The CT reaction creates electrical carriers on the polymer chain (usually positive polarons a.k.a. holes) while the dopant molecules remain in the film as counterions. Undesirably, strong electrostatic attraction from the anions of most dopants will localize the polarons and reduce their mobility. We employ a new strategy utilizing substituted icosahedral dodecaborane (DDB) clusters as molecular dopants for conjugated polymers. DDBs provide a unique system in which the redox potential of the dopant can be rationally tuned via modification of the substituents without significant change to the size or shape of the dopant molecule. These clusters allow us to disentangle the effects of energetic offset on the production of free and trapped carriers in DDB-doped poly-3-hexylthiophene (P3HT) films. We find that by designing our cluster to have a high redox potential and steric protection of the core-localized electron density, highly delocalized polarons with mobilities equivalent to films doped with no anions present are obtained.1 P3HT films doped with these boron clusters have conductivities and polaron mobilities roughly an order of magnitude higher than films doped with conventional small-molecule dopants such as 2,3,5,6-tetrafluoro-7,7,8,8- tetracyanoquinodimethane (F4TCNQ). The spectral shape of the IR-region absorption for our DDB-doped polymer film closely matches the calculated theoretical spectrum for the anion at infinite distance from the polaron.2 We therefore conclude that these DDB clusters are able to effectively spatially separate the counterion. Moreover, nearly all DDB-produced carriers are free, while it has been shown that small m

  9. Chemistry Department Seminar

    "Atomic Quantum Clusters: Novel Materials at Sub-Nanometric Level"

    Presented by David Buceta, Nanomag Group, University of Santiago de Compostela, E-15782 Santiago de, Spain

    Wednesday, May 22, 2019, 11 am
    Room 300, Chemistry Bldg. 555 - 3rd floor

    Hosted by: Jose Rodriguez

    Atomic Quantum Clusters (AQCs) are formed by a small number of atoms (< ≈ 150) and represent a new family of compounds with novel and fascinating properties, which strongly differ from both, bulk and nanoparticles of the same material. For example, fluorescent, magnetic, catalytic, etc. properties have been found in AQCs1, which are not exhibited for the same material in larger sizes. In the last years soft chemical methods have been developed to synthesize AQCs without using protecting or capping ligands2, which may hinder their properties. This offers now the possibility to explore their properties in detail. In this talk it will be firstly summarized the state-of-the art of the kinetic-control synthesis methods, explaining in detail the mechanisms involved in such methods3. To show the precise control on the size of AQCs, which can be achieved with these methods, we will explain the synthesis of monodisperse samples of Cu5-AQCs and Ag3-AQCs. Secondly, we will focus on some important applications of clusters in catalysis, highlighting the particular consequences in biomedicine4.

  10. Chemistry Department Colloquium

    "Anineutrino Reactor Monitoring"

    Presented by Professor Patrick Huber, Virginia Tech

    Monday, March 4, 2019, 11 am
    Hamilton Seminar Room, Bldg. 555

    Hosted by: Minfang Yeh

    Nuclear reactors are the brightest man-made neutrino sources and have been the workhorse of neutrino physics since the discovery of the neutrino. In the 1970s Lev Mikaelyan realized that neutrinos also can be used to learn about the internal state of a nuclear reactor. The past decade has seen a significant increase in the interest in reactor neutrinos, thanks to the theta-13 experiments and the search for sterile neutrinos. In particular, I will discuss case studies we have performed for the historical case of the 1990s nuclear crisis in the Democratic People's Republic of Korea and for the IR-40 reactor in Iran. I will report on on-going efforts to develop suitable detectors for surface deployment close to a nuclear reactor and comment on the role coherent elastic neutrino nucleus scattering may play. With the most recent results from PROSPECT, CHANDLER and others, for the first time, a real world capability exists and I will present recent efforts by an international group of reactor neutrino experts with regards to North Korea, which were published in Science [Science, 362, (2018) 649-650)].

  11. Chemistry Department Colloquium

    "Atomic Simulation and Data Science Applied to Catalysis"

    Presented by Eric A. Walker, State University of NY at Buffalo

    Tuesday, February 19, 2019, 11 am
    Hamilton Seminar Room, Bldg. 555

    Hosted by: Ping Liu

    Atomic simulation is able to solve more chemical problems than ever before due to advances in high performance computing and data science tools. Two case studies are presented to illustrate this point. One case study is the water-gas shift reaction catalyzed by platinum clusters deposited on metal oxide (Pt/MO2). The water-gas shift reaction is the most widely applied reaction in industry for the production of hydrogen which is an environmentally-friendly fuel. Furthermore, water-gas shift may be conducted on domestically produced shale gas, alleviating foreign dependence on oil. Three hypotheses regarding the active site for the water–gas shift reaction are the interface edge of Pt/MO2 catalysts, the interface corner, and the platinum terrace (pure platinum). The hypotheses are tested against experimental kinetic data. Uncertainties associated with density functional theory (DFT) calculations and model errors of microkinetic models of the active sites are informed and verified using Bayesian inference and predictive validation on the experiments. Our results suggest the metal oxide support is essential for the activity of the catalyst for water-gas shift, which aids the rational design of catalysts for the water-gas shift reaction. In the second case study, large data sets of organic reactions are investigated using machine learning tools. Reactions which are not labeled with a solvent are automatically labeled, which impacts automated chemical process design and may be utilized as an every-day tool by chemists. The machine learning solvent selections are tested against an expert chemist. In a broad sense, the methods developed within this work improve the reliability of atomic simulations and the incorporation of machine learning to catalysis research.

  12. Chemistry Department Seminar

    "Theoretical and in situ studies for the reactivity of metal-ceria (111) surfac-es: Importance of strong metal-support interactions"

    Presented by M. Verónica Ganduglia-Pirovano, Instituto de Catálisis y Petroleoquímica Consejo Superior de Investigaciones Científicas,, Spain

    Friday, February 15, 2019, 11 am
    Room 300, 3rd floor, Chemistry Bldg. 555

    Hosted by: Sanjaya Senanayake

    Metal-ceria catalysts are promising systems for industrially important reactions such as the water-gas shift reaction for hydrogen production, methane dry reforming (DRM: CH4+CO2 ? 2H2+2CO), and the direct conversion of methane to methanol (DMTM: CH4+ ½ O2 ? CH3OH). However, the complexity of real (powder) catalysts hinders the fundamental understanding of how they work, which is essential for their rational design. Specifically, the role of ceria in the catalytic activity of ceria-based systems is still not fully understood. To unravel it, well-defined ceria-based model cata-lysts consisting of metal nanoparticles deposited on a ceria surface are prepared experimentally or created theoretically and investigated. In this talk, recent results on ceria-supported Ni, Co and Cu model catalysts will be discussed, as examples of catalysts for DRM.1-3 The emphasis is here put on theoretical studies in combination with experiments using ambient pressure X-ray photoelectron spectroscopy, and special attention is given to the effects of ceria as catalyst support. The ability of ceria to stabilize oxidized species (MOx: Co2+ and Ni2+) on the CeO2 surface, by relocalizing electrons on localized f-states, and metal-lic ones (Co0, Ni0) on the reduced CeO2-x support, is essential for CH4 activation ?that occur at tem-peratures as low as 300 K? and its reforming at relatively low temperatures (~700 K). Also, the Ni/ceria system is considered for H2O activation and methanol synthesis from methane and wa-ter.4,5

  13. Condensed-Matter Physics & Materials Science Seminar

    "Novel Electrochemistry for Fuel Cell Reactions: Efficient Synthesis and New Characterization Methods"

    Presented by Zhixiu Liang

    Wednesday, February 6, 2019, 4:30 pm
    Bldg. 480 Conference Room

    Hosted by: Jing Tao

    The ever increasing consumption of fossil fuels for transportation causes climate change causing a growing concern about their future availability and further adverse environmental effects. To address this issue, the concept of CO2 neutral fuels-based energy cycle was brought out. The key reactions in that concept are electrochemical methanol oxidation (MOR), ethanol oxidation reaction (EOR), and CO2 reduction reaction (CO2RR). These all are elctrocatalysis research challenges being slow even at the best catalyst that hamper application of fuel cells, and bring environmental benefits. My research made these improvements of catalysts for the key reactions. In-situ electrochemical infrared reflective absorbance spectrum (EC-IRRAS) reveals that at lower temperature, such reaction is not complete and generates more formate; at elevated temperature, such reaction is complete to carbonate. Ethanol is one of the ideal fuels for fuel cells, but requires highly improved catalysts. Au@PtIr/C catalyst was synthesized with a surfactant-free wet-chemistry approach. Transmission electron microscope (TEM) characterization confirms the monolayer/sub-monolayer Pt-Ir shell, gold core structure. The catalyst has a very high mass activity of 58 A/mg at peak current. In situ EC-IRRAS reveals that C-C bond is cleaved upon contact with the catalyst surface leading to ethanol complete oxidation to CO2. Related researches on methodologies, included in situ TEM to help obtaining catalysts improvements, give morphologic, structural and spectroscopic information at wide range from hundreds of microns to sub-nanometer coupled with various detectors. Microelectromechanical System (MEMS) based chips technology enables TEM observation in operando, with liquid-flow-cell chips and electrochemistry chips designed and fabricated. Ag@Au hollow cubes synthesis via galvanic replacement of Au on Ag cubes was investigated with in situ TEM. The results demonstrate abnormal react

  14. Symposium on the 60th Anniversary of the Life-Saving Technetium-99m

    Wednesday, November 7, 2018, 3 pm
    Hamilton Seminar Room, Bldg. 555

    Speakers will present talks on technetium and nuclear medicine, including the history of the development of the Tc-99m generator at Brookhaven. The talks will be followed by a reception in the Chemistry Lobby.

  15. Chemistry Department Seminar

    "Synchrotron-based X-ray Absorption Spectroscopy for In Situ and Operando Studies of Nanoporous Catalysts"

    Presented by Kirill A. Lomachenko, European Synchrotron Radiation Facility (ESRF), Grenoble, France, France

    Monday, November 5, 2018, 11 am
    Room 300, Chemistry Bldg. 555

    Hosted by: Anatoly Frenkel

    X-ray absorption spectroscopy (XAS) has proven to be a very powerful tool for rationalization of catalytic processes because of the possibility to determine oxidation state and coordination geometry of catalytically active species in operando regime. The seminar will be focused on the advanced facilities for chemical XAS studies available at BM23 and ID24 beamlines of the ESRF synchrotron, which allow to exploit simultaneously a wide range of complementary techniques, make use of flexible sample environment, and obtain high-quality data in the timescale from minutes down to milliseconds. As a case study, recent work on the investigation of the local environment and electronic structure of the active centers of Cu-zeolites in deNOx and methane-to-methanol processes will be discussed.

  16. NSLS-II Friday Lunchtime Seminar

    "Materials Tribology: An Application-Driven Field with Rich Opportunities for Fundamental Studies of Surface Chemistry, Physics, Structure"

    Presented by Brandon A. Krick, Department of Mechanical Engineering and Mechanics, Lehigh University

    Friday, November 2, 2018, 12 pm
    NSLS-II Bldg. 743 Rm 156

    Hosted by: Ignace Jarrige

    The significant economic (~3-6% of developed countries GDP) and environmental (several percent of our annual energy consumption) impacts of friction and wear make tribology is an important, application-driven field. However, there is an opportunity and need for inherently fundamental studies on surface chemistry, physics and structure to elucidate fundamental mechanisms for friction and wear. The non-equilibrium and transient nature of shear-induced changes caused by contacting surfaces in relative motion requires both in situ and ex situ advanced characterization techniques; many of these only available at the light source at Brookhaven. A brief overview of shear-induced (sliding friction/wear) alterations of surfaces will be presented for material systems including: - environmental and tribochemistry molybdenum disulphide based coatings for space applications - shear-induced band bending in GaN - mechanochemistry of polymer nanocomposites

  17. Chemistry Department Seminar

    ""Size control of supported metals for catalysis""

    Presented by Xiao Yan Liu, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China), China

    Tuesday, October 30, 2018, 11 am
    Room 300 - 3rd Flr. Chemistry Bldg. 555

    Hosted by: Sanjaya Senanayake

    Catalysis by supported metals is size sensitive, so the size control is extremely important. Here, I will present two examples for the size control of catalysis. One is the size control of gold catalysts by tuning the metal support interaction. In the last decade, we've developed several methods to control the particle size of gold, for example, adding a second metal to form alloy with gold, using the thiolated gold nanoclusters as the precursor of gold catalysts, and so on. The other example focuses on single-atom catalysis that has emerged as a new frontier in heterogeneous catalysis and shown distinctive performances in a series of oxidation and hydrogenation reactions. The ways we developed to stabilize the single atoms will be introduced. The mechanism for the stabilization of the nanoparticles/single atoms were proposed based on the characterization by aberration-corrected HAADF-STEM, in situ EXAFS and DFT calculations.

  18. PubSci at the Parrish

    "Illumination: Revealing the Secret Chemistry of Oil Paintings"

    Friday, September 21, 2018, 7 pm
    Parrish Art Museum 279 Montauk Hwy., Water Mill, N

  19. Chemistry Department Colloquium

    "Proton-Coupled Electron Transfer in Catalysis and Energy Conversion"

    Presented by Dr. Sharon Hammes-Schiffer, Department of Chemistry, Yale University

    Monday, September 10, 2018, 11 am
    Hamilton Seminar Room, Bldg. 555

    Hosted by: Mehmed Zahid Ertem

    Proton-coupled electron transfer (PCET) reactions play a vital role in a wide range of chemical and biological processes. This talk will focus on recent advances in the theory of PCET and applications to catalysis and energy conversion. The quantum mechanical effects of the active electrons and transferring proton, as well as the motions of the proton donor-acceptor mode and solvent or protein environment, are included in a general theoretical formulation. This formulation enables the calculation of rate constants and kinetic isotope effects for comparison to experiment. Recent extensions enable the study of heterogeneous as well as homogeneous interfacial PCET processes. Applications to PCET in molecular electrocatalysts for hydrogen production and water splitting, photoreduced zinc-oxide nanocrystals, and the Volmer reaction will be discussed. These studies have identified the thermodynamically and kinetically favorable mechanisms, as well as the role of proton relays, and are guiding the theoretical design of more effective catalysts. In addition, recent developments of theoretical approaches for simulating the ultrafast dynamics of photoinduced PCET, along with applications to solvated molecular systems and photoreceptor proteins, will be discussed.

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