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Nanostructured Bimetallic, Trimetallic and Core-Shell Fuel-Cell Catalysts with Controlled Size, Composition, and Morphology (NIRT CBET-0709113) Jin Luo 1, Peter N. Njoki 1, Derrick Mott 1, Bridgid Wanjala 1, Rameshwori Loukrakpam 1, Bin Fang 1, Xiajing Shi 1, Khalid Alzoubi 2, Susan Lu 2, Lichang Wang 4, Bahgat Sammakia 3, and Chuan-Jian Zhong 1 *, Department of 1 Chemistry, 2 Systems Science and Industrial Engineering, 3 Mechanical Engineering, State University of New York at Binghamton; 4 Department of Chemistry & Biochemistry, Southern Illinois University at Carbondale, USA Abstract: Active, robust, and low-cost catalyst is a key component for the commercialization of fuel cells. The development of effective strategies for the synthesis and processing of multimetallic nanoparticles with controllable size and composition is an important approach to the catalyst preparation. This poster focuses on the results from an investigation of bimetallic, trimetallic, and core-shell nanoparticle catalysts for fuel cell testing. The characterization of the size, shape, composition and phase properties of the multimetallic nanoparticles and catalysts is described. The electrochemical characterization of the electrocatalytic properties of the catalysts for fuel cell reactions is discussed along with preliminary evaluation of some of the catalysts under fuel cell testing conditions. The results are also discussed in terms of activity and stability of the catalysts based on theoretical computation and statistical optimization to gain fundamental insights into the design and control parameters of fuel cell catalysts. Fuel Cell and Catalysts Goals: Trimetallic Nanoparticles & Catalysts Relative Mass Activities for ORR Spot (size)PtVFe 10 (area)341650 11 (3nm)341650 12 (3nm)331552 13 (6nm)321355 Composition321355 Pt 32 V 14 Fe 54 /C HTEM-EDX analysis EDX Analysis of Composition Pt V Fe Comparison of relative electrocatalytic activities. Examples: Pt 32 V 14 Fe 54 /C (31% loading),Pt 31 Ni 34 Fe 35 /C (30% metal loading) and standard Pt/C (20% metal loading) catalysts. Insert: Rotating Disk Electrode data for catalysts on glassy carbon electrode in 0.5 M H 2 SO 4. (5 mV/s, and 2000 rpm). For More Information: Email Contact: * C.J. Zhong: cjzhong@binghamton.edu; Web: http://chemistry.binghamton.edu/ZHONG/zhong.htm Summary Bimetallic, trimetallic, and core-shell nanoparticle catalysts with controlled size, composition and phase properties have been shown to exhibit high electrocatalytic activity. Experimental, theoretical, and statistic analysis results have shown that the size and composition of multimetallic nanoparticles play an important role in regulating the electrocatalytic activity and stability. These multimetallic nanocatalysts are being characterized and evaluated under fuel cell conditions in terms of activity and durability. Fuel cell polarization curves of MEA with Pt/C catalyst (20% loading). Pt loading: 1.0 mg/cm 2, MEA active area: 5 cm 2. Fuel Cell Testing Support References 1.Luo, J.; Wang, L.; Mott, D.; Njoki, P. N.; Kariuki, N. N.; Zhong, C. J. He, T., J. Mater. Chem., 2006, 16, 1665. 2.Luo, J.; Han, L.; Kariuki, N. N.; Wang, L.; Mott, D.; Zhong, C. J.; He, T., Chem. Mater., 2005, 17, 5282. 3.D. Mott, J. Luo, P. Njoki, Y. Lin, L. Wang, C. J. Zhong, Catalysis Tod., 2007, 122, 378 4.X. Shi, J. Luo, P. Njoki, Y. Lin, T. H. Lin, D. Mott, S. Lu, C. J. Zhong, Ind. Eng. Chem. Res., 2008, 47, 4675. 5.Zhong, C. J.; Luo, J.; Njoki, P. N.; Mott, D.; Wanjala B.; Loukrakpam, R.; Lim, S. I-I.; Wang, L.; Fang, B.; Xu, Z., Energy & Environ. Sci, 2008, 1, 454. 6.J. Luo, L.Y. Wang, D. Mott, P. Njoki, Y. Lin, T. He, Z. Xu, B. Wanjala, S. I-Im Lim, C. J. Zhong, Adv. Mater., in press. Evaluation of the activity and durability of membrane electrode assembly (MEA) in fuel cells Characterization of electrocatalytic activity and stability of the multimetallic catalysts using RDE technique Optimization and Identification of the best catalysts Preparation of PtVFe Nanoparticles Preliminary results from density functional theory (DFT) calculations for O 2 on Pt m V n Fe l and Pt nanoparticles show that the oxygen reduction reaction is favorable on Pt m V n Fe l in comparison with Pt due to direct or spontaneous O 2 dissociations. O 2 dissociation on Pt m V n Fe l nanoparticles is limited by the active sites (Pt-V or Pt-Fe) available. Stability Selecting M 1 and M 2 can be based on Pareto optimization plot. A set of solutions is said to be Pareto optimal if it cannot be improved upon without hurting one of the objectives. PtNiZr General correlation between two different properties (Activity and Stability) for catalyst (M 1 ) x (M 2 ) y Pt 1-x-y Activity DFT Calculations Optimization Analysis : frozen states of bulk bimetallic metal system : data for bulk bimetallic metal system : bimetallic composition determined from XRD : bimetallic composition determined from DCP-AES. Bulk: Nanoscale: Bimetallic Nanoparticles & Catalysts High conversion efficiency Low pollution Light weight High power density Fuel cell voltage: E cell = E Nernst + η act (i.e., η act(cathode) - η act(anode) ) – η ohmic FTIR of CO Adsorption on Au n Pt 100-n /SiO 2 XRD of Au n Pt 100-n /C ORR: Oxygen Reduction Reaction Optimal balanced activity and stability for (Ni) x (Zr) y Pt 1-x-y } + Pareto optimization Core-Shell Catalysts Existing Catalysts: Low activity High Pt loading (high cost) Poor stability Reduce Pt loading Increase activity & stability Understand design parameters Discover new catalysts NIRT
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