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Analysis of the Promoter-Catalyst interaction between Mn and Rh by Transmission Electron Microscopy Ben Graham Department of Materials Science and Engineering , University of Alabama at Birmingham Robert Klie , PhD Department of Physics, University of Illinois at Chicago. Introduction.
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Analysis of the Promoter-Catalyst interaction between Mn and Rh by Transmission Electron Microscopy Ben Graham Department of Materials Science and Engineering, University of Alabama at Birmingham Robert Klie, PhD Department of Physics, University of Illinois at Chicago
Introduction • An alternative source of energy is a major concern for society. • Draw Backs for traditional fermentation routes include: • Slow conversion process • Inefficient conversion process • By-products (such as ammonia) • the Fischer-Tropsch mechanism can convert syngas(or bio-gas) to higher octane fuels such as ethanol. • It is possible to increase the activity and selectivity of the mechanism by adding a catalyst and promoter. • Catalyst of interest is Rhodium promoted by Manganese
Introduction SEA strategy for increased promoter-metal interactions catalysts EELS mapping of SEA promoted catalyst Sample was prepared in previous study Electron Energy Loss Spectroscopy (EELS) collects the inelastically-scattered electrons to determine chemical bonding. J.R. Regalbuto, Catalyst Preparation: Science and Engineering, Taylor & Francis/CRC Press, Boca Raton, 2006, pp. 297.
Introduction J. Liu and et al, Selective Absorption of Manganese onto Rhodium for optimized Mn/Rh/SiO2 Alcohol Synthesis Catalysts. print.2013.
JEM 3010, basic TEM was used Transmitted elastically scattered electrons can be assembled into bright field images (composed of phase and mass contrast) TEM D.B. Williams, C.B. Carter, Transmission Electron Microscopy. 1996, New York, Springer Science,7-141.
TEM D.B. Williams, C.B. Carter, Transmission Electron Microscopy. 1996, New York, Springer Science,7-141.
TEM Images 3% Rh/CNT sample at 600Kx, atomic resolution of particles 3% Rh/CNT sample at 300Kx, ideal for particle sampling
TEM Images 2% Mn/3%Rh/CNT sample at 600Kx, atomic resolution of particles 2% Mn/3%Rh/CNT sample at 300Kx, ideal for particle sampling 1.96 nm total 9 fringes 0.22 nm each (111) orientation Emaps.mrl.uiuc.edu
Particle Size Measurements • Average particle size for 3%Rh/CNT: 1.9 ±0.6 nm • Average Particle Size for 1%Mn/3%Rh/CNT 2.1 ± 0.5nm 3% Rh/CNT Count 1%Mn/3%Rh/CNT Average Particle Size (nm) Count Average Particle Size (nm)
Particle Size Measurements • Average particle size for 2% Mn/3%Rh/CNT: 3.2 ± 0.6 nm • Distribution for all samples were Gaussian or normal. 2%Mn/3%Rh/CNT Count Average Particle Size (nm)
Particle Orientation a= Lattice parameter d= measured d-spacing (hkl)= corresponding miller indices 3.57nm 16 Fringes 0.223 nm each In (111) plane 2%Mn/3%Rh/CNT image at 600k J. Liu and et al, Selective Absorption of Manganese onto Rhodium for optimized Mn/Rh/SiO2 Alcohol Synthesis Catalysts. print.2013.
Discussion STEM Dark Field Image of 2%Mn/3%Rh/CNTs (left) STEM Dark field image composed of Z-contrast TEM bright field image composed of phase and mass contrast Rh Mn J. Liu and et al, Selective Absorption of Manganese onto Rhodium for optimized Mn/Rh/SiO2 Alcohol Synthesis Catalysts. print.2013.
Conclusions & Future Work • Determined nano-particle size for promoted and un-promoted rhodium on carbon nano-tubes • Found evidence of manganese-rhodium interactions • Increase in particle size • Decrease in lattice parameter • Examine Rh particles on a Mn substrate • Electron Diffraction analysis of samples
Acknowledgments • NSF grant – EEC-NSF Grant #1062943 • Nanoscale Physics Group • Research Recourses Center East staff • Dr. Takoudis, Dr. Jursich, and REU Staff Thank You! Questions?
