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Plasma-Assisted Synthesis of Molybdenum Carbide Catalysts

Plasma-Assisted Synthesis of Molybdenum Carbide Catalysts. Marisa Theroux-Jones University of Illinois at Chicago Energy Systems Laboratory Advisors: Profs. A. Saveliev, K. Brezinsky Graduate Student: Gabriel Duran RET: Kara Boyle August 3, 2006. Purpose & Motivation.

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Plasma-Assisted Synthesis of Molybdenum Carbide Catalysts

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  1. Plasma-Assisted Synthesis of Molybdenum Carbide Catalysts Marisa Theroux-Jones University of Illinois at Chicago Energy Systems Laboratory Advisors: Profs. A. Saveliev, K. Brezinsky Graduate Student: Gabriel Duran RET: Kara Boyle August 3, 2006

  2. Purpose & Motivation • Trying to find effective & efficient method to create Mo2C • Mo2C can replace expensive precious metal catalysts • Cheaper & more efficient • Water-Gas Shift Reaction (WGS) • CO + H2O → CO2 + H2 • Fuel cell applications • Main Objectives • Study the parameters of the reactor • Make the reactor more efficient • Vary the concentration of ethylene

  3. Chemistry Behind Forming MoC Mo C2H4 Ar+ H e- H e- Plasma e- Ar+ e- 10,000 to 100,000 K C H H Ar+ e- e- Ar+ C ~ 300 K Output = Mo2C

  4. High voltage Argon EPS Ethylene Non-thermal Plasma High voltage Two-Chamber Reactor

  5. Changes to Make the Reactor More Efficient • Main concern: not collecting enough particles • ~15% yield • New filters • 40 to 26 micron • Mo = 44 micron • New part to close gap

  6. Changes to Make the Reactor More Efficient • Problem:breakdown occurring between top plates • when putting in ~1 g, yield ~0.15 g • Solution:add ½ gram of Mo powder instead of 1 gram

  7. Changes to Make the Reactor More Efficient • Problem:lowest vacuum pressure ~4 torr • Possible leak in system, letting in air • Solution:reseal all connections • Pressure decreased to approx. Ø torr

  8. Results of Solutions • Collecting more mass • Old system: 15% yield • New system: 30-51% yield • Plasma color • From pink/orange to bright blue

  9. Analysis of Reacted Mo Particles: TEM • Transmission Electron Microscope (TEM) • Can show d-spacing • Each compound has unique length • Top Picture • 2.77 ± 0.06 Å • MoC = 2.74 • Bottom Picture • 2.18 ± 0.02 Å • MoO2 = 2.18

  10. Analysis of Reacted Mo Particles: X-ray Photoelectron Spectroscopy (XPS) Green = reacted Mo powder Black = Mo powder MoxOy Mo Mo2C Intensity (CPS) Mo Bond Energy (eV)

  11. Conclusions • The reactor is creating MoC, Mo2C • May or may not be creating MoO • TEM • XPS • System modifications provided higher % yield • From 15% to 30-51% • Over small range of ethylene, no significant change

  12. Future Work • One chamber reactor • Clean with H2 to remove oxides • Use silver tape instead of carbon for XPS • More XPS analyses • Test catalytic activity with water-gas shift reaction

  13. References • "Catalytic Converter." Wikipedia, The Free Encyclopedia. 8 Apr 2004, 19:26 UTC. Wikimedia Foundation, Inc. 19 Jun 2006 <http://en.wikipedia.org/w/index.php?title=Catalytic_Converter&oldid=16415808>. • Kizling, M.B. and Jaras, S.G. (1996) “A review of the use of plasma techniques in catalyst preparation and catalytic reactions.” Applied Catalysts A: General. 147, 1-21. • Colver, G. M. et al. (1996) “An electrostatic suspension method for testing spark breakdown, ignition, and quenching of powders.” Journal of Electrostatics. 37, 151-172. • York, Andrew. Magic Catalysts. Chemistry in Britain, August 1999 • Liu, Chang-jun et al. Catalyst preparation using plasma technologies. Catalysis Today, 2002 • "Transmission electron microscopy." Wikipedia, The Free Encyclopedia. 21 Jun 2006, 01:23 UTC. Wikimedia Foundation, Inc. 22 Jun 2006 <http://en.wikipedia.org/w/index.php?title=Transmission_electron_microscopy&oldid=59728878>. • “X ray Crystallography.” Chemistry Department. June 2006. Northwestern University. 22 June 2006. • “Molybdenum Carbide”. Nowotny et al. Monatsh. Chem., v85 p255 (1954) • Moon, Dong Ju and Ryu, Jong Woo. “Molybdenum carbide water-gas shift catalyst for fuel-powered vehicles applications.” Catalysis Letters. January 2004. 92, 17-24.

  14. Acknowledgements Thank you: • NSF EEC-0453432 Grant • Novel Materials and Processing in Chemical and Biomedical Engineering • Prof. C.G. Takoudis & Prof. Linninger • DoD - ASSURE • University of Illinois at Chicago • Prof. Saveliev • Gabriel Duran • Everyone in the Energy Systems Lab • John Roth in RRC • Kara Boyle, RET Fellow

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