One-pot synthesis of mesoporous Cu-γ-Al2O3 as bifunctional catalyst for direct dimethyl ether synthesis

Mesoporous copper-alumina (Cu-Al2O3) with different copper contents was synthesized in a one-pot reaction via the evaporation-induced self-assembly of Pluronic P123 and the corresponding metal precursors in ethanolic solution in the presence of nitric acid. Mesoporous Cu-Al2O3 calcined at 400 degrees C exhibits a large BET surface area of 265 m(2)/g and a pore volume of 0.48 cm(3)/g. XRD results indicate that the wall of mesoporous Cu-Al2O3 calcined at 400 degrees C is amorphous, and that it is transformed to crystalline material by further thermal treatment at 800 degrees C. Copper was formed as very small particles in the composite under 5% H-2 flow at high temperature. Moreover, the mesoporous structure did not collapse after the sample was reduced at 650 degrees C for 4 h, and the copper particles with sizes of around 6 nm were well distributed through the entire mesoporous gamma-Al2O3 network. Using the mesoporous Cu/gamma-Al2O3 as a bifunctional catalyst for one-step dimethyl ether synthesis from synthesis gas, a CO conversion of 72% and a DME selectivity of 69% were obtained at 50 bar and 310 degrees C. (C) 2012 Elsevier Inc. All rights reserved.