Production of hydrogen from dimethyl ether on supported Au catalysts

Abstract

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/CeO 2 is the most effective catalyst. On Au/Al 2 O 3 catalyst the main process was the formation of methanol with a very small amount of hydrogen. Deposition of Au on CeO 2 -Al 2 O 3 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/CeO 2 interface. Adding potassium promoter to Au/CeO 2 -Al 2 O 3 catalyst further enhanced the production of hydrogen as indicated by the increase of the yield to ∼87%. No deactivation of the catalyst was experienced at 773 K for the measured time, ∼10 h.

CO2 Recycling to Dimethyl Ether: State-of-the-Art and Perspectives

“…Recently, steam reforming of methanol is receiving attention because of the relative low process temperature (around 300 °C) and simpler reactor configurations [ 32 ]. Nevertheless, due to the high toxicity of methanol, DME is also considered a reliable candidate for hydrogen production by steam reforming (by adopting similar operation conditions of methanol steam reforming and over a bifunctional catalyst, namely an acid function for DME hydrolysis to methanol and a copper-based catalyst for the alcohol reforming), being not toxic and with a high hydrogen content [ 33 , 34 , 35 , 36 ].…”

Catalytic reforming of dimethyl ether in microchannels

“…CH 3 OCH 3 + (3-n) H 2 O + n/2 O 2 → (6-n) H 2 + 2 CO 2 (1) The catalytic reforming of DME at moderate temperature consists of two consecutive reactions; first, DME is hydrolyzed to methanol over an acid catalyst, and then methanol is subsequently transformed into a mixture of H 2 and CO x over a metal function with the participation of the water gas shift reaction (WGS). Acidity of the catalyst is supplied by the support, usually γ-Al 2 O 3 , ZrO 2 , WO 3 /ZrO 2 and zeolites such as ZSM-5 [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23], but also tungstosilicoheteropolyacids, Ga 2 O 3 /TiO 2 and Mo 2 C [24][25][26], whereas the metal function is usually based on Cu (normally CuZn or Cu/CeO 2 ) [27][28][29][30][31][32][33][34][35][36][37][38][39] or Pd (Pd or PdZn) [40][41][42][43], although the use of other metals such as Ni, Pt, Rh, Ru and Au [44][45][46][47][48][49][50]…”

Photocatalytic decompositions of methanol and ethanol on Au supported by pure or N-doped TiO2

“…As the generation of H 2 free of CO is one of the challenges in heterogeneous catalysis, the catalytic behavior of Au has also been tested from this aspect. It was found that supported Au particles effectively catalyze the production of H 2 in the thermal decompositions of HCOOH [6][7][8][9][10], CH 3 OH [11][12][13][14][15][16][17][18], C 2 H 5 OH [19][20][21][22][23] and CH 3 OCH 3 [24] at 423-573 K. Pure, CO-free H 2 was obtained, but only in the catalytic decomposition of HCOOH at higher temperatures [6][7][8]. A further development in this topic was the production of H 2 by photocatalytic decomposition of the above compounds over supported Au samples at room temperature [25][26][27][28][29][30][31][32].…”