Magnesium Modified Mesh-TYPE Cu/γ-Al2O3/Al Catalysts: Low Acid Density Catalysts for Methanol Steam Reforming.

Methanol steam reforming (MSR) is regarded as one of the effective technologies for in-situ hydrogen generation. A novel mesh-type γ-Al2O3/Al support was prepared by anodization technology. To decrease dimethyl ether (DME) yield in MSR system, magnesium was doped to the γ-Al2O3/Al to modify acidity. The results show that the acid density of the γ-Al2O3/Al support can be decreased from 1.423 μmol/m2 to 1.122 μmol/m2, resulting in the decrease in DME yield from 70.2 to 16.7%. Meanwhile, various CuMgx/γ-Al2O3/Al catalysts were prepared and the effects of MgO on the distribution and reducibility of CuO on the support were investigated. The results show that the dispersion of CuO was improved and reduction temperature was decreased with Mg doping. Finally, four pieces of mesh structured CuMg/γ-Al2O3/Al catalysts (4*8 cm2) were applied into the microreactor with the channel height of 2 mm. CuMg/γ-Al2O3/Al catalyst showed excellent catalytic performance with 100% methanol conversion, 98.2% hydrogen yield, without DME at 250 °C, 4000 mL/(g h) GHSV. Furthermore, the diffusion limitation was investigated by Damköhler number (Da), the results indicated the diffusion influence can be neglected in the microreactor over mesh-type catalysts. [ABSTRACT FROM AUTHOR]