Hydrotreating of crude 2-ethylhexanol over Ni/Al2O3 catalysts: Influence of the Ni oxide dispersion on the active sites

To analyze the correlation between the Ni species dispersion and the surface active sites, we prepared a series of Ni/γ-Al2O3 samples by conventional impregnation method (CI), conventional deposition method (CD), hydrothermal impregnation method (HI), and hydrothermal deposition method (HD). It was found that the number of surface active sites of the four samples with a similar Ni loading follows the order: H-D (13.2 μmol gcat−1) > H-I (10.3 μmol gcat−1) > C-I (8.6 μmol gcat−1) > C-D (7.3 μmol gcat−1). The samples with the highest Ni oxide dispersion (H-I) and the lowest Ni oxide dispersion (C-D) are all not of benefit to increase the number of active sites. Because the high dispersion results in most Ni ions embedding into the inner part of the support and the low dispersion suppresses the exposure of active sites, the Ni oxide particles with an appropriate size are helpful to obtain more active centers.

Graphical abstractThe correlations of Ni species dispersion and the surface active sites on Ni/γ-Al2O3 catalysts were studied. The samples with the highest Ni oxide dispersion (H-I) and the lowest Ni oxide dispersion (C-D) are not helpful to obtain more active sites, whereas the Ni oxide particles with an appropriate size (H-D) are beneficial to enhance the number of active centers.Figure optionsDownload full-size imageDownload high-quality image (78 K)Download as PowerPoint slide