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Basic Energy Sciences Directorate
CFN, Chemistry, Condensed Matter Physics & Materials Science
Jim Misewich
Associate Laboratory Director for Basic Energy Sciences
BNL is at the center of a large, vibrant research
community in the Northeast, offering access to world-class user facilities
and scientists in a highly collaborative and interdisciplinary environment.
A BES Complex is envisioned that integrates our science and facilities, and
is coupled to university and industrial partners, and to other major
research facilities at BNL.
The Basic Energy Sciences directorate (BES) consists of
three components: the Condensed Matter Physics and Materials Science
department (CMPMSD), the Chemistry Department (CHEM), and the Center for
Functional Nanomaterials (CFN). The CFN, like all the DOE nanoscience
research centers, serves both as a user facility and as a science
department. Overall, the strategy of the BES directorate and all its
components are strongly aligned with the BNL energy strategy, and in
particular, with the complex materials, catalysis science, and solar energy
themes of the BNL energy strategy. We note that the BNL energy strategy
contributes to the nation’s energy security challenges by addressing a
subset of the key scientific grand challenges identified by the DOE Office
of Basic Energy Sciences:
- How do remarkable properties of matter emerge from complex
correlations of atomic and electronic constituents and how can we control
these properties? (Complex materials theme)
- How do we design and perfect atom-and energy-efficient synthesis
of new forms of matter with tailored properties? (Catalysis science theme)
- Can we master energy and information on the
nanoscale to create
new technologies with capabilities rivaling those of living systems? (Solar
energy theme)
CMPMSD is primarily aligned with the complex materials
theme of the BNL energy strategy, and in particular the superconductivity
part of that theme. CMPMSD also contributes to the solar energy theme
through work on photovoltaic materials and thermoelectric materials. The
Chemistry department is primarily aligned with the catalysis theme of the
BNL energy strategy but also makes major contributes to the solar energy
theme, particularly in solar fuels. The CFN plays a significant role in the
lab energy strategy as one of the pillars, along with NSLS, NSLS-II, and New
York Blue, providing a platform for understanding the role of nanostructured
materials for energy applications. In addition to the broad role that the
CFN plays nationally as a major user facility providing the tools and
expertise for nanoscience research, the CFN also plays a major role in the
BES directorate’s energy science strategy. The science themes of the CFN (nanocatalysis/interface
science, electronic nanomaterials, and soft/bio nanomaterials) are aligned
with the BNL energy strategy themes in catalysis and solar energy.
The major goals of the directorate in our energy themes are:
- Complex materials: To lead in the
synthesis of the highest quality complex materials and to develop an
understanding of the emergent phenomena in these complex systems for the
rational exploration of novel material with enhanced properties.
- Catalysis science:
To understand and control the state of nano-catalysts
at the atomic level in real time and under operating conditions.
- Solar energy:
To explore the role of nanostructured and novel materials and assemblies for
enhancement of solar fuel production and solar electricity generation.
The BES Directorate is
playing an increasing role in laying the groundwork for a robust applied R&D
program by delivering a science-base energy program that has a focus on
applications and by creating appropriate new research alliances.
Complex Materials
As
exemplified by the ternary and quaternary perovskite oxides, the advent of
structurally and chemically complex materials has led to the discovery of
new classes of materials that often exhibit the most extreme physical
properties, including high temperature superconductivity in the cuprate
family. The latter discovery and the observation of strong electronic
correlations in these materials, has stimulated an enormous research effort.
However, the complexity of these materials and elusive mechanism for high
temperature superconductivity remains a grand challenge in materials
science. The importance of superconductivity to the nation’s energy strategy
is illustrated in the DOE-Basic Energy Science Report from the Workshop on
Superconductivity. In addition, in a recent DOE-BESAC report, understanding
and controlling the remarkable emergent properties of complex and correlated
materials was identified as one of the five grand challenges for science and
the imagination.
The complex materials theme is the major theme of the CMPMS
department, which is already playing an internationally recognized leading
role in correlated electron materials. The CMPMSD business plan outlines our
strategy, which is driven by four key issues where Brookhaven is positioning
itself to provide leadership: the pairing mechanism in high temperature
superconductivity, the role of competing orders, the role of dimensionality,
and understanding quantum critical phenomena. This strategy employs a strong
experimental program with a growing emphasis of synthesis of materials and a
strong theory component which is working closely with the experimental team.
As mentioned in the summary our goal is to lead in the synthesis of the
highest quality complex materials and to develop an understanding of the
emergent phenomena in these complex systems for the rational exploration of
novel material with enhanced properties.
Catalysis Science
The
DOE-BES Basic Research Needs workshop on Catalysis has identified catalysis
science as one of the key research directions that can secure national
energy needs and address global warming, which are perhaps the two most
scientifically challenging problems of this century. Reduction of the energy
consumption needed for chemical transformations, increase in the efficiency
of energy production, conversion and use from fossil fuels, and mitigation
of the environmental impact of these processes will all depend on the
development of future catalysts. Furthermore, innovative catalysts are needed
for the supply of renewable, sustainable, clean fuels from sunlight to
fulfill the daunting projected global energy demand. The catalysis science
theme in the BES directorate is carried by two units: the Chemistry
Department, which has widely recognized leadership in catalysis particularly
in nanocatalysts for electrochemistry, and the new Center for Functional
Nanomaterials (CFN), which has already developed unique new tools for the
in-situ study of catalysis. Much of the Brookhaven role in catalysis can be
associated with redox chemistry at interfaces.
This includes themes such as
fuel cell electrocatalysis, carbon reduction reactions, solar-induced water
splitting, and catalysis for the hydrogen economy. In addition, the
directorate is developing a unique suite of tools for understanding
catalysis in-situ including: participation in the catalysis consortium at
NSLS, high-pressure photoemission, environmental transmission electron
microscopy, and scanning tunneling microscopy in a catalytic flow reactor.
Supporting this is a strong, integrated theory effort that spans both the
Chemistry Department and the CFN. As mentioned above, the goal of the
catalysis science theme is to understand and
control the state of nano-catalysts at the atomic level in real time and
under operating conditions.
Solar Energy
The
most abundant renewable and carbon-neutral source of energy is solar. The
DOE-BES Workshop report on Solar Energy Utilization points out that more
energy strikes the surface of the earth in one hour than is utilized by the
planet in an entire year. However, the fuel and electricity generated
through solar technology represents only a very small fraction of the energy
consumed by society. Two of the three research opportunities identified by
the DOE-BES Solar Energy Utilization report are solar electricity and solar
fuels. The Brookhaven Solar Energy strategy is focused on these two areas
and the BES directorate has nascent programs contributing to our solar
energy theme. Although the solar energy theme is the newest and least
developed of the directorate themes, the emergence of the CFN, NSLS-II, and
the New York Blue computing facility provides Brookhaven with an outstanding
and complete set of complementary tools to synthesize, probe, and understand
nanostructured materials and interfaces with unprecedented precision and
resolution.
In concert with our core research programs we have an
opportunity to develop a significant solar energy program to provide new
materials and understanding of nanostructured forms of matter for the
optimization of charge transport, energy flow, and chemical reactivity. The
directorate goal in our solar energy theme is to
explore the role of nanostructured and novel materials and assemblies for
enhancement of solar fuel production and solar electricity generation.
Enhanced Applied Research Programs
The current DOE focus on the nature of research is that
it be translational in nature, i.e. the range of programs be from discovery
to deployment. Energy is a major thrust of the current administration with
an emphasis on delivery of science and technology to practice. For these
reasons, technology transfer and commercialization are increasingly
important for DOE. R&D opportunities in the applied domain are strong. To
transition to a more translational approach there needs to be a greater
connection between BES, applied science and industry. The paths to achieving
these goals are via organizational change and increased research alliances.
Industrial partnerships are a key element of many current opportunities.
The organizational change to be more translational is
the creation of the Global and Regional Solutions Directorate (GARSD). The role of
the GARSD is to: 1) deliver national and regional impact through accelerated
deployment of technology that meets the highest needs, 2) build and enhance
an applied R&D program that is attractive to partners and respected for
quality, 3) be a strong regional partner with industry and universities
interested in the same kind of impact, 4) enhance the experience of the
private sector’s interactions with the Laboratory, and 5) bring the needs of
the market to seeds from discovery.
Increased research alliances are being achieved by
becoming a resource for the New York State and the northeast region, and by
establishing a regional presence in business development and
entrepreneurship. BES is providing leadership and/or outreach to the
following initiatives: NY State Smart Grid Consortium, NY Battery and Energy
Storage Technology (NY-BEST) Teams, and the SBU/NYS Small Business
Development Center.
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Combining
synchrotron-based band structure measurements, theoretical calculations,
and atomic-resolution microscopy, a group of researchers at the Center
for Functional Nanomaterials (CFN) led by Peter Sutter have established
the electronic structure of graphene on transition metals, such as
ruthenium and platinum. The resulting understanding of the interaction
of graphene with metal surfaces provides the basis for the synthesis of
large-scale graphene on metals. A novel approach established in this
work for rapidly assessing the band structure in micron-sized areas of
interest will find broad use to determine the electronic properties of
functional materials, such as catalysts or organic semiconductors for
inexpensive, large-area photovoltaics. [Appl. Phys. Lett. 94, 133101 (2009); Nano
Letters 9, 2654 (2009)]
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CFN scientists led by Oleg Gang have developed a novel
method for producing dimers of DNA-encoded nanoparticles with remarkably
high yields, thus overcoming one of the obstacles that have prevented
solution-based methods from efficiently producing small clusters of nano-objects
(such as gold nanoparticles or quantum dots) for energy-related
applications. The method, which incorporates two different DNA strands
on a single nanoparticle, was used to assemble both homogenous
(gold-gold) and heterogeneous (gold-silver) nanoparticle dimers with
nanoscale optical properties. Because this method is scalable to large
quantities and more complex clusters, it may become a practical way of
inexpensively fabricating predictable and reliable nanostructures with
customized properties. [Nature Materials 8, 388 (2009)]
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As part of her research program at the CFN, Ping Liu has
done large-scale computer calculations to study the binding energies of
reactive intermediates and energy barriers for key reactions involving
Ni2P (001), a new catalyst for the water-shift reaction that
exhibits activities larger than Cu (100), which is the best known metal
surface catalyst for that reaction. The surprising feature of the Ni2P
surface responsible for the large catalytic activity turned out to be
the presence, under catalytic conditions, of adsorbed oxygen on it, as
verified by X-ray photoemission experiments carried out by scientists of
BNL’s Chemistry Department. The calculations show that the presence of
oxygen results in a significant reduction of the effective barrier for
the reaction. [J. Catalysis 262, 294 (2009)]
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A group from CMPMSD led by Peter Johnson introduced new
analysis methods into the photoemission technique to allow detailed
studies of the spectral function above the chemical potential for the
first time. These new approaches revealed a particle-hole asymmetry in
the cuprate superconductors that had not been identified before and
provided an indication that previously observed “Fermi Arcs” might in
fact be one side of closed Fermi pockets. Thus a new picture of the
Fermi surface associated with the pseudogap regime has emerged. The
study also provided strong evidence for localized pre-formed Cooper
pairs in the normal state of these materials. [Nature 456 (7218), 77-80
(2008)]
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Ivan Bozovic led a group from CMPMSD that has
successfully demonstrated enhanced interfacial superconductivity in the
interface between two materials that are normally non-superconducting,
the materials being an insulator ( La2CuO4) and a metal (
La1.55Sr0.45CuO4). The group was able to demonstrate that this highly
robust phenomenon is confined within 2 - 3nm of the interface. If such a
bilayer is exposed to ozone, Tc exceeds 50 K, and this enhanced
superconductivity is also shown to originate from an interface layer
about 1 - 2 unit cells thick. [Nature 455 (7214), 782-785, (2008)]
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In a study reported by Atonio Checco, dynamic atomic
force microscopy in the noncontact regime has been used to study the
morphology of a nonvolatile liquid (squalane) as it spreads along
wettable nanostripes embedded in a nonwettable surface. The study
showed that the liquid profile depends on the amount of lateral
confinement imposed by the nanostripes, and that it is truncated at the
microscopic contact line in good qualitative agreement with classical
mesoscale hydrodynamics. However, the width of the contact line is
found to be significantly larger than expected theoretically. This
behavior may originate from small chemical inhomogeneity of the
patterned stripes as well as from thermal fluctuations of the contact
line. [Physical Review Letters, 102, 106103-106106 (2009)]
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New electrocatalyst for
efficient conversion of C-C bond in fuel cells:
The direct conversion of chemical energy to electrical energy in fuel
cells offers the promise of higher efficiency power sources for mobile
and stationary applications. While hydrogen fuel cells have progressed,
a barrier to general mobile fuel cell use is the challenge of direct use
of liquid fuels with difficult-to-break C-C bonds. A recent advance has
demonstrated that a nanostructured multi-component electrocatalyst based
on a combination of atomically dispersed catalytic metals on a
catalytically active oxide support, for instance platinum and rhodium
atoms on carbon-supported tin dioxide nanoparticles, is capable of
oxidizing ethanol with high efficiency and holds great promise for
resolving the impediments to developing practical direct ethanol fuel
cells.
This electrocatalyst effectively splits the C–C bond in ethanol
at room temperature in acid solutions, facilitating its oxidation at low
potentials to CO2, which has not been achieved with existing
catalysts. Experiments and density functional theory calculations
indicate that different components of the electrocatalyst give activity
for different reaction steps, and that interactions among the components
are important in tuning the activities. These findings point to the way
to accomplishing the C–C bond splitting in other electrocatalytic
processes and demonstrate the promise in further understanding the
controlled synthesis of nanostructured multi-component catalytic
materials. (Nature Materials 8 (4), 325-330, April 2009).
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Heterogeneous catalysts are
key to the industrial production of essential chemicals, energy
production and removal of atmospheric pollutants which have enormous
impact on the US economy and human health. A promising approach to
developing the next generation of more efficient catalysts is to tailor
their chemical activity by controlling the size of the active catalysts
particles and their interaction with the support material. The ability
to prepare such “nanocatalysts” was recently demonstrated byresearchers who
used gas-phase cluster beams to deposit size-selected nanoclusters of
molybdenum sulfide (MoxSy) onto a solid surface.
Molybdenum sulfide is an active catalyst for removing potentially
harmful sulfur contaminants from chemical feedstocks, and exploring its
activity as a function of particle size, structure and metal-to-sulfur
ratio provides a unique approach to optimizing its catalytic activity.
Moreover, the use of size-selected nanoclusters allows the application
of powerful computational methods for calculating their atomic
structures which are nearly impossible to obtain experimentally. A
combined experimental and theoretical study of the interaction of MoxSy
nanoclusters with simple probe molecules (CO and NH3) in the
gas-phase and supported on a gold surface resulted in new insights into
how the atomic structures change with size and how the nanocluster-support
interaction modifies their chemical activity. These results demonstrate
the utility of using size-selected cluster techniques in combination
with theory for understanding how nanocatalysts work and how they might
be modified for enhanced catalytic activity. (Journal of Physical
Chemistry C 223 (30): 11495-11506 July 31 2008; Journal of
Physical Chemistry A 112 (47); 12011-12021 November 27 2008).
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New
semiconductor materials for solar energy conversion to fuels: Solar
fuels production is scientifically challenging because very stable
molecules – water and carbon dioxide – have to be converted to more
energy-rich molecules. Energy and catalysts are required to drive
reactions of these molecules uphill to generate fuels. Among the
approaches being pursued are coordinated experimental and theoretical
studies of solar-driven water oxidation achieved through direct
excitation of band-gap-narrowed semiconductors (BGNSCs), combined with
appropriate catalysts to drive chemistry following light absorption.
Two new studies of novel light absorbing photocatalyst semiconductors
show promising paths forward:
- Preparation of (Ga1-xZnx)(N1-xOx) Photocatalysts
from the Reaction of NH3 with Ga2O3/ZnO and ZnGa2O4: In Situ
Time-Resolved XRD and XAFS Studies: Gallium zinc oxynitrides
(Ga1-xZnx)(N1-xOx) are important due to their visible-light
photocatalytic activity. Using in situ time-resolved X-ray
diffraction (XRD), we have monitored the formation of wurtzite
(Ga1-xZnx)(N1-xOx) compounds during the solid-state reaction of NH3
with Ga2O3/ZnO mixtures on a ZnGa2O4 spinel. The ZnGa2O4 spinel was
found to be a key intermediate in the formation of
(Ga1-xZnx)(N1-xOx) and imposes a limit on the zinc content in the
gallium zinc oxynitrides. Journal of Physical Chemistry C 113
(9) 2650-2659 March 2009
- Water Adsorption on
the GaN Nonpolar Surface: A first-principles study of water
adsorption on a wurtzite GaN surface elucidated the structures and
energetics of water adsorption and the energy barrier for water
dissociation. Water was found to adsorb dissociatively; the energy
barrier for the dissociation is negligible. This has important
implications for the intrinsic water splitting catalysis activity of
this new visible-absorbing semiconductor for solar water splitting.
Journal of Physical Chemistry C 113 (9) 3365-3368 March 2009
Last Modified: July 28, 2011
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