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CATALYTIC ETHANOL STEAM REFORMING

CATALYTIC ETHANOL STEAM REFORMING. Am. Chem. Soc., Div. Pet. Chem. 2008 , 51 p.1&2. Handbook of Green Chemistry, Wiley 2008. Topics in Catalysis, in press. Science, in press. M. Scott B.Sc. M.Sc.(hons) Department of Chemistry The University of Auckland.

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CATALYTIC ETHANOL STEAM REFORMING

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  1. CATALYTIC ETHANOL STEAM REFORMING Am. Chem. Soc., Div. Pet. Chem. 2008, 51 p.1&2 Handbook of Green Chemistry, Wiley 2008 Topics in Catalysis, in press Science, in press M. Scott B.Sc. M.Sc.(hons) Department of Chemistry The University of Auckland

  2. Traditional Energy non-sustainable H2 from ethanol Renewable Efficient

  3. Renewable energy cycle ∆

  4. The catalyst • Cerium dioxide nanoparticles as the supporting material. • Rhodium metal dissociates sp3 C-H bond • Rh/CeO2 dissociates C-C bond of ethanol • Palladium excels in hydrogenation and oxidation Bimetallic Rh,Pd/CeO2 displays ideal properties

  5. Steam ReformingAn activated process 298K; Ethanol on reduced Rh/CeO2 CO J. Catal. 208, 393-403 (2002)

  6. Catalyst manufacture Precipitation pH 9 773 K CeO2 nano-particles Deposition

  7. Catalytic testing • 6:1 water to ethanol ratio shows higher CH4 conversion than 3:1 ratio => higher H2 vol. % • Effects of varying reaction temperature • Effects of varying weight percentage loading noble metal • Varying throughput (2.5, 5, 6.5 and 11.5 mL/hour)

  8. Temperature dependence CH3CH2OH → CH4 + CO + H2 ΔH0 = 50 kJ/mol CO + H2O → CO2 + H2 ΔH0 = -41 kJ/mol CH4 + 2H2O → CO2 + 4H2 ΔH0 = 164 kJ/mol

  9. Temperature Programmed Desorption CO2 Acetaldehyde CeO2 500K & 773K Water CH3 CH4 CH3CH2- CO CO2 1%Pd,1%Rh/CeO2 375K & 525K CH3CH2- Acetaldehyde

  10. Effect of metal loading 11.5 mL/hour, 6:1 and 773K

  11. Transmission Electron Microscopy Used catalyst Used catalyst Pd,Rh alloy • Alloying of Rh and Pd • Reduction of Rh2O3 • Restructuring of Support • Origins at interface • Lowering CN of Cerium

  12. CH3CH2OH + 3H2O → 6H2 + 2CO2 ∆H=173 kJ/mol • Rh/CeO2 based catalyst • Bimetallic catalyst very active • Low metal loadings show best activity • Active sites at Rh-Ce and Pd-Ce interface • High temperature required for CH4 oxidation • CH4 reforming and CO oxidation inadequate • Dramatic restructuring occurring • Activation of catalyst occurring • No signs of deactivation

  13. Future research • In situ FTIR • TPD studies • Further XPS studies • Near Edge X-ray Absorption Fine Structure • Further PAS and TEM • Maximise outflow • Doping • ⅓wt.%Rh,⅓wt.%Pd,⅓wt.%Ni/Ce0.75Zr0.25O2

  14. Inverse Opal Ceria Transmission Electron Scanning Electron Microscopy Microscopy 20000x • 3D macroporous structure • Resistant to sintering to 1073K • Allow gas low through pores • High surface to volume ratio 100000x Chem. Mater. 2008, 20, 1183–1190

  15. Acknowledgments: Associate Professor Hicham Idriss Supervisor Dr Geoffrey Waterhouse, Dr William Chiu, Dr Maria Goeffrey University of Auckland Graduates Alister Gardiner and Simon Arnold Industrial Research Limited, Christchurch Professor Jordi Llorca (HRTEM)Universitat Politècnica de Catalunya, Barcelona, Spain Dr Steven J. Pas (PAS) Commonwealth Scientific and Industrial Research Organisation (CSIRO) Manufacturing and Materials Technology, Victoria, Australia Mark Blackford (TEM) Australia’s Nuclear Science and Technology Organisation, Lucas Heights, Sydney, Australia

  16. XPS 1%Rh,1%Pd/CeO2 and PAS 1 Ethanol + 3 water at 773 K, 3 hours at ca. 100 Torr EB = hν – (φ + EK) • Oxidation of CeO2 • Reduction of metal • Homogenization • Growth of voids PAS 2%Rh,2%Pd/CeO2 Voids in the bulk

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