کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
55390 | 47050 | 2012 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Glycerol hydrogenolysis to 1,2-propanediol with Cu/γ-Al2O3: Effect of the activation process Glycerol hydrogenolysis to 1,2-propanediol with Cu/γ-Al2O3: Effect of the activation process](/preview/png/55390.png)
We have used Cu/γ-Al2O3 catalysts submitted to different activation protocols (calcination, reduction in H2/Ar, and reoxidation in N2O/N2) in order to investigate the role of the different copper surface species and acid properties in glycerol hydrogenolysis to 1,2-propanediol (1,2-PDO) under mild reaction conditions (493 K, 2.4 MPa H2). The activated catalysts have been characterized by temperature-programmed reduction (TPR), temperature-programmed desorption of NH3 (TPD-NH3), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and diffuse reflectance infrared Fourier transform spectroscopy of adsorbed CO (DRIFT-CO). The significant different catalytic performance obtained with the Cu/γ-Al2O3 solids is not integrally related to their acid properties, surface Cu species also participate in the glycerol conversion. Partially reduced copper species (Cu+) promotes glycerol conversion rates. Activated catalysts follow the sequence: reoxidation > reduction > calcination, when glycerol conversion is compared. Moreover, Cu species are mostly responsible for the observed 1,2-PDO selectivity values. It is strongly dependent on the Cu0/Cu+ atomic ratio and on the surface concentration of both Cu0 and Cu+ species. Accordingly, 10CuAl-c-r catalyst showed the best behavior in glycerol hydrogenolysis to 1,2-PDO.
Figure optionsDownload high-quality image (135 K)Download as PowerPoint slideHighlights
► The activation protocol of Cu/Al2O3 catalyst is relevant on its catalytic behavior.
► The intrinsic activity sequence of Cu species is: reoxidized > reduced > calcined.
► 1,2-PDO selectivity is strongly dependent on the Cu0/Cu+ surface atomic ratio.
► The results suggest that Cu0 species are the most selective to 1,2-PDO.
Journal: Catalysis Today - Volume 187, Issue 1, 30 June 2012, Pages 122–128