Adsorption and Structure of Platinum Nanoparticles On Boron-Doped Carbon Supports

Monday, November 8, 2010
Hall 1 (Salt Palace Convention Center)
Zhongtao Zhang1, C. Heath Turner1, Katherine Phillips2, Ashley Rice1, Wei An1, Chethan Acharya3, Chandan Srivastava4, GiHan Kwon1, Tonya Klein1 and Gregory Thompson5, (1)Chemical and Biological Engineering, University of Alabama, Tuscaloosa, AL, (2)Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, (3)Mechanical and Aerospace Engineering, University of California at San Diego, San Diego, CA, (4)Materials Engineering, Indian Institute of Science, Bangalore, India, (5)Metallurgical and Materials Engineering, University of Alabama, Tuscaloosa, AL

The binding between transition-metals and carbon materials (such as activated carbon) plays a key role in catalyst performance and durability. Also, the contacts between transition-metals and other forms of carbon (graphenes and carbon nanotubes) are critical interactions for next-generation electronics. In order to characterize these interactions, we are using a variety of computational and experimental methods. Moreover, we are attempting to tune the metal-carbon interactions by introducing substitutional boron dopants in the carbon materials. In this work, we have primarily focused on the interaction of platinum particles with pristine and boron-doped carbon supports. Our computational investigations include spin-polarized density-functional theory (DFT), which allows us to quantify the metal-support binding energies, as well as the electronic structures and properties of the systems. With this information, we have generated a map of the potential-energy surface of Pt on pristine and boron-doped carbon surfaces. This information is fit to a simple, analytical expression, which is now being used in large-scale molecular dynamics simulations. In order to support this work, XPS experiments are simultaneously being used to characterize the metal-support binding energies, and TEM analysis is being used to visualize the deposited Pt nanoparticle structures. Overall, we find that the Pt-carbon binding energy can be significantly enhanced with the addition of substitutional boron dopants in the carbon support, and the doping procedure is experimentally shown to increase catalyst lifetime. Along with applications in catalysis, we find that the electronic and magnetic properties of boron-doped carbon nanotubes can tuned by pairing these materials with different transition-metals. Furthermore, metal-carbon contacts can be significantly stabilized if the carbon nanotubes are doped with boron.

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