Hydrogen production by dimethyl ether steam reforming over copper alumina catalysts prepared using the sol–gel method

• We have developed outstanding new catalysts for steam reforming of dimethyl ether.
• Several copper alumina catalysts are prepared using by the sol–gel method.
• Each catalyst is used for DME steam reforming without mixing of acid catalysts.
• The sol-gel method is very optimal for preparation of SRDME catalysts.
• The H2 yield is 95% and the CO concentration is 0.8 mol.% at 270 °C of SRDME over the Cu–Zn(29–1 wt.%)/Al2O3 catalyst prepared by the sol–gel method.

Several copper alumina catalysts prepared using the sol–gel method were examined for the production of hydrogen from dimethyl ether (DME). Each of the catalysts　was used individually　for DME steam reforming, without mixing of DME hydrolysis catalysts such as alumina and zeolite. In order to obtain hydrogen by DME steam reforming, mixed catalysts with DME hydrolysis catalysts and methanol steam reforming catalysts are usually used based on the reaction mechanism. However, the rate of hydrogen production in the single use of copper alumina catalysts prepared using the sol–gel method is faster than those of mixed catalysts. SEM-EDS analysis confirmed that alumina and copper coexist and are well dispersed on the surfaces of sol–gel copper alumina catalysts. Therefore, two reactions of DME hydrolysis over alumina sites and methanol steam reforming over copper sites occur more sequentially in the case of sol–gel catalysts than in the case of mixed catalysts. Several experiments also suggest that Cu–Zn(29–1 wt.%)/Al2O3 catalyst prepared using the sol–gel method is the best catalyst for more hydrogen production and less CO production from DME. DME steam reforming over the catalyst at 275 °C showed the following data; DME conversion: 95%, yield of H2: 95%, and CO concentration: 0.8 mol.%. We have developed some outstanding new catalysts that produce hydrogen from DME at the low reforming temperature.

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