Computational Investigation of Metal Clusters on Doped Carbon Supports
EMSL Project ID
24792
Abstract
Many electronic, chemical, and physical properties are known to depend upon system size, especially when the length scale approaches nanometer or sub-nanometer dimensions. With regards to catalysis, it is recognized that the activity of a catalyst is not a pure function of its surface area. In fact, as the size of a catalyst shrinks, the catalyst behaves less like a bulk metal, and characteristics such as the morphology of the particles and the nature of the support begin to play a significant role. For a number of reasons, carbon (in its various forms) is commonly used as the support material in many catalytic and electrochemical applications, including fuel cell catalysis, decarbonylation reactions, reductive amination, alcohol synthesis, etc. Due to the high price (and limited quantities) of these precious metals, it is particularly important to maintain their original activity under reacting conditions for extended periods of time. Harsh reacting conditions may quickly result in a loss of chemical activity, due to catalyst poisoning, sintering, or dissolution of the catalyst or its support material. We plan to use a combined experimental and computational approach to develop a better understanding of how the interactions between metal catalyst particles (Pt, Ru, and Au) and carbon support materials might be manipulated in order to preserve or enhance catalyst function. In our work, we plan to stabilize the catalyst particles and/or increase their catalytic ability on carbon supports by testing the atomic-level doping of the supports.
Our preliminary electronic structure calculations have shown that simple doping procedures may lead to significant improvements in catalyst stability. To build on this exploratory work, we are now planning ways to further manipulate carbonaceous supports, in order to improve catalytic performance and lifetime. Experimentally and computationally, we have the capability to synthesize and thoroughly characterize the support materials, tightly control the dispersion of the metal nanoparticles, directly monitor catalyst sintering and diffusion, and quantify the catalytic properties of the resulting metal-support system. The experiments (conducted at UA) will involve applying a newly-developed nanocluster sputtering source to perform combinatorial materials science of the interaction of size-selected metal clusters with pure carbon, carbon-nitride, carbon-boron and carbon-boron-nitride thin films. Advanced characterization with an environmental TEM will enable the dynamic structure of the nanoclusters to be observed, and the catalytic activity of the nanoclusters will be gauged using x-ray photoelectron spectroscopy and thermal desorption studies. Computationally, we will calculate metal-support binding energies, cluster geometry, charge distributions on the surface and within the metal cluster, HOMO/LUMO analysis, nanoparticle diffusion coefficients, band structure, and catalytic activity (for CO oxidation). For the computational component of this project, we are requesting supercomputer time on the MPP2 at PNNL, and we have carefully estimated our time requirements on this machine (123,904 SUs) from running previous calculation on it, using the VASP simulation package.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2007-05-23
End Date
2010-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Acharya, CK, and CH Turner. 2008 “Co Oxidation with Pt(1 1 1) Supported on Pure and Boron-Doped Carbon: A Dft Investigation.” Surface Science 602(23): 3595-3602. (U Alabama – MSCF) doi:10.1016/j.susc.2008.09.037
Acharya CK, and C Turner. 2007. "Effect of an Electric Field on the Adsorption of Metal Clusters on Boron-Doped Carbon Surfaces." Journal of Physical Chemistry C 111:14804-14812. doi:10.1021/jp073643a
Acharya, C. K., Sullivan, D. I., and Turner, C. H., "Characterizing the interaction of Pt and PtRu clusters with boron-doped, nitrogen-doped, and activated carbon: DFT calculations and parameterization", Journal of Physical Chemistry C 112, 13607-13622 (2008).
An W, and CH Turner. 2009. "Electronic Structure Calculations of Gas Adsorption on Boron-doped Carbon Nanotubes Sensitized with Tungsten." Chemical Physics Letters 482(4-6):274-280. doi:10.1016/j.cplett.2009.10.008
An W, and CH Turner. 2010. "Linking Carbon and Boron-Nitride Nanotubes: Heterojunction Energetics and Band Gap Tuning." The Journal of Physical Chemistry Letters 1(15):2269-2273. doi:10.1021/jz100753x
An W, and CH Turner. 2010. "Linking Carbon and Boron-Nitride Nanotubes: Heterojunction Energetics and Band Gap Tuning." The Journal of Physical Chemistry Letters 1(15):2269-2273. doi:10.1021/jz100753x
An W, and CH Turner. 2010. "Structural, Electronic, and Magnetic Features of Platinum Alloy Strings Templated on A Boron-Doped Carbon Nanotube." Physical Review. B, Condensed Matter and Materials Physics 81(20):205433-1 through 205433-8. doi:10.1103/PhysRevB.81.205433
An W, and CH Turner. 2010. "Structural, Electronic, and Magnetic Features of Platinum Alloy Strings Templated on A Boron-Doped Carbon Nanotube." Physical Review. B, Condensed Matter and Materials Physics 81(20):205433-1 through 205433-8. doi:10.1103/PhysRevB.81.205433
An W, and CH Turner. 2009. "Chemisorption of Transition-Metal Atoms on Boron- and Nitrogen-Doped Carbon Nanotubes: Energetics and Geometric and Electronic Structures." Journal of Physical Chemistry C 113(17):7069 - 7078. doi:10.1021/jp9000913
An W, and CH Turner. 2009. "Transition-Metal Strings Templated on Boron-Doped Carbon Nanotubes: A DFT Investigation." Journal of Physical Chemistry C 113(34):15346-15354. doi:10.1021/jp9052715
An W, D Gatewood, BI Dunlap, and C Turner. 2011. "Catalytic Activity of Bimetallic Nickel Alloys for Solid-Oxide Fuel Cell Anode Reactions from Density-Functional Theory." Journal of Power Sources 196(10):4724-4728. doi:10.1016/j.jpowsour.2011.01.007
An W, L Wintzinger, CH Turner, and Y Bao. "A Combined Computational/Experimental Study of Fluorescent Gold Nanocluster Complexes." , Pacific Northwest National Laboratory, Richland, WA. [Unpublished]
An W, XC Zeng, and CH Turner. 2009. "First-principles Study of Methane Dehydrogenation on a Bimetallic Cu/Ni(111) Surface." Journal of Chemical Physics 131(17):174702/1-174702/11. doi:10.1063/1.3254383
Bao N, L Shen, W An, P Padhan, CH Turner, and A Gupta. 2009. "Formation Mechanism and Shape Control of Monodisperse Magnetic CoFe2O4 Nanocrystals." Chemistry of Materials 21(14):3458-3468. doi:10.1021/cm901033m
Bao Y, W An, CH Turner, and KM Krishnan. 2010. "The Critical Role of Surfactants in the Growth of Cobalt Nanoparticles." Langmuir 26(1):478–483. doi:10.1021/la902120e
Palchoudhury S, Y Xu, W An, CH Turner, and Y Bao. 2010. "Platinum Attachments on Iron Oxide Nanoparticle Surfaces." Journal of Applied Physics 107(9):09B311-1 through 09B311-3. doi:10.1063/1.3355899
Palchoudhury S, Y Xu, W An, CH Turner, and Y Bao. 2010. "Platinum Attachments on Iron Oxide Nanoparticle Surfaces." Journal of Applied Physics 107(9):09B311-1 through 09B311-3. doi:10.1063/1.3355899