Molybdenum carbide (Mo 2 C) was demonstrated to be highly active for the water-gas shift of a synthetic steam reformer exhaust stream. This catalyst was more active than a commercial Cu-Zn-Al shift catalyst under the conditions employed (220-295 • C and atmospheric pressure). In addition, Mo 2 C did not catalyze the methanation reaction. There was no apparent deactivation or modification of the structure during 48 h on-stream. The results suggest that high surface area carbides are promising candidates for development as commercial water-gas shift catalysts.

A spatial confinement effect of copper nanoparticles in an ordered mesoporous γ-Al2O3, which is synthesized by an evaporation induced self-assembly (EISA) method, was investigated to verify the enhanced catalytic activity and stability with less aggregation of copper crystallites during direct synthesis of dimethyl ether (DME) from syngas. The surface acidity of the mesoporous Al2O3 and the metallic copper surface area significantly altered catalytic activity and stability. The ordered mesopore structures of Al2O3 were effective to suppress the aggregation of copper nanoparticles even under reductive CO hydrogenation conditions through the spatial confinement effect of the ordered mesopores of Al2O3 as well as the formation of strongly interacted copper nanoparticles with the mesoporous Al2O3 surfaces by partial formation of the interfacial CuAl2O4 species. The aggregation of copper nanoparticles on the bifunctional Cu/meso-Al2O3 having an ordered mesoporous structure was effectively suppressed due to the partial formation of the thermally stable spinel copper aluminate phases, which can further generate new acid sites for dehydration of methanol intermediate to DME.

No abstract

No abstract

No abstract