Production of hydrogen from dimethyl ether on supported Au catalysts

The adsorption and reactions of dimethyl ether (DME) were investigated on Au nanoparticles supported by various oxides and carbon Norit. Infrared spectroscopic and temperature programmed desorption studies revealed that DME adsorbs readily on most oxidic supports. A limited dissociation of DME to methoxy species was established on Au particles by IR spectroscopy. As regards the formation of hydrogen, Au/CeO2 is the most effective catalyst. On Au/Al2O3 catalyst the main process was the formation of methanol with a very small amount of hydrogen. Deposition of Au on CeO2-Al2O3 mixed oxide resulted in a very active catalyst for H-2 production. The yield for H-2 in the reforming of DME approached the value of 73% at 723-773 K. This feature was explained by the hydrolysis of DME to methanol on alumina, and the fast decomposition of methanol at the Au/CeO2 interface. Adding potassium promoter to Au/CeO2-Al2O3 catalyst further enhanced the production of hydrogen as indicated by the increase of the yield to similar to 87%. No deactivation of the catalyst was experienced at 773 K for the measured time, similar to 10 h. (C) 2010 Elsevier B.V. All rights reserved.