Hydrogen Formation in the Reactions of Methanol on Supported Au Catalysts
- 188 Downloads
The adsorption and reactions of methanol have been investigated on Au metal supported by various oxides and carbon Norit of high surface area. Infrared spectroscopic studies revealed the dissociation of methanol at 300 K, which mainly occurs on the oxide-supports yielding methoxy species. The presence of Au already appeared in the increased amounts of desorbed products in the TPD spectra. The reaction pathway of the decomposition and the activity of the catalyst sensitively depend on the nature of the support. As regards the production of hydrogen the most effective catalyst is Au/CeO2 followed by Au/MgO, Au/TiO2 and Au/Norit. In contrast, on Au/Al2O3 the main process is the dehydration reaction yielding dimethyl ether. On Au/CeO2 the decomposition of methanol starts above ~500 K and approaches total conversion at 723–773 K. The products are H2 (~68%) and CO (~27%) with very small amounts of methane and CO2. The decomposition of methanol follows the first order kinetics. The activation energy of this process is 87.0 kJ/mol. The selectivity of H2 formation at 573–773 K was ~90%, this value increased to 97% using CH3OH:H2O (1:1) reacting mixture indicating the involvement of water in the reaction. No deactivation of Au catalysts was experienced at 773 K in ~10 h. It is assumed that the interface between Au and partially reduced ceria is responsible for the high activity of Au/CeO2 catalyst.
KeywordsFTIR spectroscopy Formation of methoxy Reaction of methanol Hydrogen production Au catalyst CeO2 support
This work was supported by OTKA under contract number NI 69327. The authors express their thanks to P. Németh for TEM measurements.
- 1.Sandstede G, Veziroglu TN, Derive C, Pottier J (eds) (1972) Proceedings of the 9th world hydrogen energy conference, Paris, France, p 1745Google Scholar
- 12.Haruta M, Kobayashi T, Sano H, Yamada N (1978) Chem Lett 2:405Google Scholar
- 16.Kung MC, Davis RJ, Kung HK (2007) J Phys Chem 111:11767Google Scholar
- 20.Ueda A, Haruta M (1999) Gold Bull 32:3Google Scholar
- 22.Mitov I, Klissurski D, Minchev C (2008) Comptes Rendus De L Acad Bulgare Des Sci 61:1003Google Scholar
- 32.Trovarelli A (ed) (2002) Catalysis by ceria and related materials. World scientific publishing company, Incorporated, USAGoogle Scholar
- 33.Bartheau MA, Madix RJ (1982) In: King DA, Woodruff DP (eds) The chemical physics of solid surface and heterogeneous catalysis. Elsevier, Amsterdam, p 95 (chapter 4)Google Scholar
- 48.Szabó ZG, Solymosi F (1961) Actes Congr Intern Catalyse 2e Paris 1960:1627Google Scholar